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  • 1.
    Asghar, A. M.
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Malick, M.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, The Institute of Technology.
    Hussain, A.
    Chalmers University of Thechnology, Gothenburg, Sweden .
    A multiwideband planar monopole antenna for 4G devices2013In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 55, no 3, p. 589-593Article in journal (Refereed)
    Abstract [en]

    This article presents a compact multiband planar antenna designed for mobile phone applications.The antenna performance is achieved by designing a planar monopole antenna into distributed radiating elements. The proposed antenna is comprised of a chopped circular radiator appended with a meander line and an L-strip coupled element, which is an extension of the ground plane. The combination of a chopped circular patch and L-shaped coupling strip residing on the top side generates lower band while upper band resonances are attained separately by chopped circular resonator and meander line elements. The antenna shows a planar structure which occupies an area of 56 x 17.6 mm and can be directly printed onto a circuit board at low cost making it especially suitable for mobile phone applications. The manufactured antenna is experimentally verified and covers several wireless communication bands, such as LTE 750, GSM 850, GSM 900, DCS, UMTS-2110, Bluetooth, WLAN, WiMAX, and UWB. The high frequency structure simulation is used to design and analyze the antenna performance, and a practical structure was fabricated and tested. The measured and simulated return loss show good agreement.

  • 2.
    Gong, Shaofang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Huynh, Allan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Owais, Owais
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Truly Differential RF and Microwave Front-End Design2010In: IEEE 11th Annual Wireless and Microwave Technology Conference (WAMICON), Piscataway, NJ, USA: IEEE , 2010, p. 1-5Conference paper (Refereed)
    Abstract [en]

    New design methodology for truly differential RF and microwave front-ends has been presented in this paper. Baluns are avoided using this design methodology, while achieving differential signaling for high noise immunity. A case study on an ultra-wide band RF front-end in the frequency band 6-9 GHz has been performed using the new design methodology, indicating that both wide bandwidth and high performance can be achieved using this design methodology. A direct comparison between single-ended and differential designs of the RF filter has also been presented in order to verify the correctness of the design methodology.

  • 3.
    Gong, Shaofang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Pushing the wireless data rate to the Internet speed2016In: IEEE Access, E-ISSN 2169-3536, Vol. 4, p. 8787-8792Article in journal (Refereed)
    Abstract [en]

    This article intends to answer the question how to achieve wireless data rates that can catch up with current Internet speed, from a basic physics point of view. It is shown that the traditional electric circuit theory and design methodology that have been used for generations are unfortunately not adequate for wireless communications in the future. Instead, disruptive approaches such as six-port modulators for processing of electromagnetic waves and optical pulses should be employed to push up the wireless data rate above 100 gigabits per second. The key variables to consider for high speed digital communications are bandwidth, modulation order and signal-to-noise ratio. In principle, it should be possible to achieve a wireless data rate at 100 Gbps within the frequency spectrum below 20 GHz.

  • 4.
    Gong, Shaofang
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Owais, Owais
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Haartsen, Jaap
    Sony Ericsson Mobile Communications AB, Lund, Sweden.
    Karlsson, Peter
    Sony Ericsson Mobile Communications AB, Lund, Sweden.
    Radio Architecture for Parallel Processing of Extremely High Speed Data2009In: IEEE International Conference on Ultra-Wideband, ICUWB, Vancouver, Canada, 9-11 Sept., IEEE , 2009, p. 433-437Conference paper (Refereed)
    Abstract [en]

    Using our own-developed frequency multiplexing network, a radio architecture for parallel radio signal processing has been proposed for achieving extremely high data rate above 10 Gbit/s. To meet the high requirement on phase linearity, amplitude balance and low noise figure in a very large bandwidth, our own-developed ultra-wideband six-port correlator has been utilized for the modulator and demodulator in the radio architecture.

  • 5.
    Gong, Shaofang
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Karlsson, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Serban Craciunescu, Adriana
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Design of a radio front-end module at 5 GHz2004In: 6th Circuits and System Symposium on Emerging Technologies: Frontiers of Mobile and Wireless Communication,2004, Piscataway, CA, USA: IEEE , 2004, p. 241-Conference paper (Refereed)
  • 6.
    Gong, Shaofang
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Xu, Xin
    Univ Elect Sci and Technol China, Peoples R China.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Broadside-Coupled Microstrip Lines as Low Loss Metamaterial for Microwave Circuit Design2019In: Wireless Communications & Mobile Computing, ISSN 1530-8669, E-ISSN 1530-8677, Vol. 2019, article id 9249352Article in journal (Refereed)
    Abstract [en]

    The entire microwave theory is based on Maxwells equations, whereas the entire electronic circuit theory is based on Kirchhoffs electrical current and voltage laws. In this paper, we show that the traditional microwave design methodology can be simplified based on a broadside-coupled microstrip line as a low loss metamaterial. That is, Kirchhoffs laws are still valid in the microwave spectrum for narrowband signals around various designated frequencies. The invented low loss metamaterial has been theoretically analyzed, simulated, and experimentally verified in both time and frequency domains. It is shown that the phase velocity of a sinusoidal wave propagating on the low loss metamaterial can approach infinity, resulting in time-space shrink to a singularity as seen from the propagating wave perspective.

  • 7.
    Gong, Shaofang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Östh, Joakim
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Six-port Modulators for High Speed Data2016In: GigaHertz Symposium 2016, Linköping, 2016, p. 65-Conference paper (Refereed)
    Abstract [en]

    Results from our recent study on six-port modulators and demodulators for high speed data transmission have shown that the six-port radio technology has the potential to catch up the speed of the Internet. This is due to the fact that the binary baseband data, either electrical or optical, can be converted directly to high order modulated RF signal without any D/A conversion. The six-port modulators and demodulators can also be designed with differential circuitry to improve the signal-to-noise ration and dynamic range. In addition, antennae and radio front-end components can be integrated on the same substrate with the six-port modulator and demodulator.

  • 8.
    Huynh, Allan
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Mixed-Mode S-Parameters and Conversion Techniques2010In: Advanced Microwave Circuits and Systems / [ed] Vitaliy Zhurbenko, INTECH , 2010, p. 1-12Chapter in book (Other academic)
    Abstract [en]

    This book is based on recent research work conducted by the authors dealing with the design and development of active and passive microwave components, integrated circuits and systems. It is divided into seven parts. In the first part comprising the first two chapters, alternative concepts and equations for multiport network analysis and characterization are provided. A thru-only de-embedding technique for accurate on-wafer characterization is introduced. The second part of the book corresponds to the analysis and design of ultra-wideband low- noise amplifiers (LNA).

  • 9.
    Karlsson, Magnus
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Implementation of digit-serial filters2005Doctoral thesis, monograph (Other academic)
    Abstract [en]

    In this thesis we discuss the design and implementation of Digital Signal Processing (DSP) applications in a standard digital CMOS technology. The aim is to fulfill a throughput requirement with lowest possible power consumption. As a case study a frequency selective filter is implemented using a half-band FIR filter and a bireciprocal Lattice Wave Digital Filter (LWDF) in a 0.35 µm CMOS process.

    The thesis is presented in a top-down manner, following the steps in the topdown design methodology. This design methodology, which has been used for bit-serial maximally fast implementations of IIR filters in the past, is here extended and applied for digit-serial implementations of recursive and non-recursive algorithms. Transformations such as pipelining and unfolding for increasing the throughput is applied and compared from throughput and power consumption points of view. A measure of the level of the logic pipelining is developed, i.e., the Latency Model (LM), which is used as a tuning variable between throughput and power consumption. The excess speed gained by the transformations can later be traded for low power operation by lowering the supply voltage, i.e., architecture driven voltage scaling.

    In the FIR filter case, it is shown that for low power operation with a given throughput requirement, that algorithm unfolding without pipelining is preferable. Decreasing the power consumption with 40, and 50 percent compared to pipelining at the logic or algorithm level, respectively. The digit-size should be tuned with the throughput requirement, i.e., using a large digit-size for low throughput requirement and decrease the digit-size with increasing throughput.

    In the bireciprocal LWDF case, the LM order can be used as a tuning variable for a trade-off between low energy consumption and high throughput. In this case using LM 0, i.e., non-pipelined processing elements yields minimum energy consumption and LM 1, i.e., use of pipelined processing elements, yields maximum throughput. By introducing some pipelined processing elements in the non-pipelined filter design a fractional LM order is obtained. Using three adders between every pipeline register, i.e., LM 1/3, yields a near maximum throughput and a near minimum energy consumption. In all cases should the digit-size be equal to the number of fractional bits in the coefficient.

    At the arithmetic level, digit-serial adders is designed and implemented in a 0.35 µm CMOS process, showing that for the digit-sizes, , the Ripple-Carry Adders (RCA) are preferable over Carry-Look-Ahead adders (CLA) from a throughput point of view. It is also shown that fixed coefficient digitserial multipliers based on unfolding of serial/parallel multipliers can obtain the same throughput as the corresponding adder in the digit-size range D = 2...4.

    A complex multiplier based on distributed arithmetic is used as a test case, implemented in a 0.8 µm CMOS process for evaluation of different logic styles from robustness, area, speed, and power consumption points of view. The evaluated logic styles are, non-overlapping pseudo two-phase clocked C2MOS latches with pass-transistor logic, Precharged True Single Phase Clocked logic (PTSPC), and Differential Cascade Voltage Switch logic (DCVS) with Single Transistor Clocked (STC) latches. In addition we propose a non-precharged true single phase clocked differential logic style, which is suitable for implementation of robust, high speed, and low power arithmetic processing elements, denoted Differential NMOS logic (DN-logic). The comparison shows that the two-phase clocked logic style is the best choice from a power consumption point of view, when voltage scaling can not be applied and the throughput requirement is low. However, the DN-logic style is the best choice when the throughput requirements is high or when voltage scaling is used.

  • 10.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Low profile antennas for UWB2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The number of wireless communication applications increases steadily, leading to the competition for currently allocated frequency bands. Pressure on authorities around the world to permit communication in higher and wider frequency ranges to achieve higher wireless capacity than those existed in the past has resulted in several new specifications. The federal communications commission (FCC) in USA has unleashed the band 3.1-10.6 GHz for ultra-wideband radio (UWB) communication. The release has triggered a worldwide interest for UWB. Capacity issues in form of data rate and latency have always been a bottleneck for broadened wireless-communication usages. The new communication systems like UWB require higher spectral efficiency than what is normally utilized with traditional antenna techniques. The interest for compact consumer electronics is growing in the meantime, creating a demand on efficient and low profile antennas which can be integrated on a printed circuit board. In this thesis, some methods to extend the spectral efficiency and other antenna parameters associated with wide band usages are developed and discussed. Furthermore, methods on how to enhance the performance when one antennaelement is not enough are studied as well.

    List of papers
    1. Wideband patch antenna array for multi-band UWB
    Open this publication in new window or tab >>Wideband patch antenna array for multi-band UWB
    2004 (English)In: Proc. IEEE 11th Symp. on Communications and Vehicular Tech., Ghent, Belgium, November, 2004Conference paper, Published paper (Refereed)
    Abstract [en]

    As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, ultra wideband radio (UWB) will utilize the frequency-band of 3.1-10.6 GHz. Microstrip patch antennas have advantages of low cost and compatibility to the printed circuit board (PCB) technology, having the possibility to integrate the antenna with the circuit board. Since patch antennas have ground planes, components can be placed on the other side of the PCB, this allows a compact module design. However, the microstrip patch antenna has drawback of small bandwidth. Bandwidth is limited since the substrate height is limited. To overcome these drawbacks, we have studied a method to use a patch array with varied patch lengths on a low loss PCB. Patches electrically far away from each other will give independent resonances. By choosing several patch lengths so that the standing wave ratio (SWR) plots of the antennas overlap, they can be combined into one wideband with a power-divider. Several arrays can be combined to a multi-band antenna system using switches. A patch antenna array for the multiband UWB in the frequency band of 3.1-10.6 GHz is presented in this paper.

    Keywords
    Ultra wideband, UWB, patch antenna, wireless, antenna array
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12793 (URN)
    Conference
    IEEE 11th Symp. on Communications and Vehicular Tech., Ghent, Belgium, November
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    2. An integrated spiral antenna system for UWB
    Open this publication in new window or tab >>An integrated spiral antenna system for UWB
    2005 (English)In: Proc. IEEE 35th European Microwave Conference, 4-6 October, Paris, France, 2005, p. 2007-2010Conference paper, Published paper (Refereed)
    Abstract [en]

    As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz. The spiral antenna has a higher spectral efficiency than other planar antennas like the patch antenna. Theoretically, any type of antennas can be combined into different kind of arrays, in order to improve performance beyond that from one single antenna. The electrically coupled parallelism is one solution to extend bandwidth. By combining two spiral antennas with different radius of the radiation zone, the standing wave ratio (SWR) can be kept low for a large bandwidth, resulting in an improved spiral antenna performance for UWB. Furthermore, a study of how spiral dimensions impact on gain and SWR was conducted and presented.

    Keywords
    uwb, antenna, ultra wideband radio, spiral antenna
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12794 (URN)10.1109/EUMC.2005.1610362 (DOI)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    3. Monofilar spiral antennas for UWB with and without air core
    Open this publication in new window or tab >>Monofilar spiral antennas for UWB with and without air core
    2007 (English)In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 2, no 1, p. 64-70Article in journal (Refereed) Published
    Abstract [en]

    One of the trends in wireless communicationis that systems require more and more frequency spectrum.Consequently, the demand for wideband antennas increasesas well. For instance, the ultra wideband radio (UWB)utilizes the frequency band of 3.1-10.6 GHz. Such abandwidth is more than what is normally utilized with asingle low-profile antenna. Low profile antennas arepopular because they are integratable on a printed circuitboard. However, the fractional bandwidth is usually anissue for low profile antennas because of the limitedsubstrate height. The monofilar spiral antenna on the otherhand has higher fractional bandwidth, and at GHzfrequencies the physical dimensions of the spiral isreasonable. Furthermore, a study of how spiral dimensionsimpact on antenna gain and standing wave ratio (SWR) wasconducted and presented. Simulated results were comparedwith measurements.

    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-12795 (URN)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    4. Air core patch antennas suitable for multi-band UWB
    Open this publication in new window or tab >>Air core patch antennas suitable for multi-band UWB
    2005 (English)In: Proc. GigaHertz 2005, Uppsala, Sweden, 2005, p. 218-221Conference paper, Published paper (Refereed)
    Abstract [en]

    As wireless communication applications grow rapidly, the demand for modular solutions with high performance and low profile antennas increases. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz. Integrateable antennas should be of planar structures. A Planar structure limits design options, regarding various performance aspects. For instance, the spectral efficiency, i.e., the bandwidth (BW) relative to the center frequency (CF) is limited. The antenna efficiency, i.e., gain relative to directivity is also limited. The antenna efficiency is important for receiver sensitivity, which is important in UWB systems. The efficiency is dependant of the antenna structure and material used. The Rogers 4350B material is suitable for high frequency modules since it has a low loss tangent that is stable over a wide frequency range, but the substrate height is limited. In this study a printed circuit board (PCB) with an air core was introduced to increase the antenna efficiency. The module is processed as two separate double-layer PCBs. This technique can be implemented to increase the performance in a narrowband as well as in a wideband antenna system. An advantage is that components can be placed on the other side of the ground plane without interference since the ground plane shields components from antenna radiation. A study of how the antenna bandwidth and efficiency are improved with the proposed structure at 3.5 and 10 GHz was conducted and presented.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12796 (URN)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
  • 11. Order onlineBuy this publication >>
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ultra-wideband Antenna and Radio Front-end Systems2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The number of wireless communication applications increase steadily, leading to the competition for currently allocated frequency bands. Pressure on authorities around the world to permit communications in higher and wider frequency ranges to achieve higher wireless capacity than those existed in the past has resulted in several new specifications. The federal communication commission (FCC) in USA has unleashed the band 3.1-10.6 GHz for ultra-wideband radio (UWB) communications. The release has triggered a worldwide interest for UWB. Other regulatory instances throughout the world have issued use of UWB techniques as well. Capacity issues in form of data rate and latency have always been a bottleneck for broadened wireless-communication usages. New communication systems like UWB require larger bandwidth than what is normally utilized with traditional antenna techniques. The interest for compact consumer electronics is growing in the meantime, creating a demand on efficient and low profile antennas which can be integrated on a printed circuit board. In this thesis, some methods to extend the bandwidth and other antenna parameters associated with wideband usages are studied. Furthermore, methods on how to enhance the performance when one antenna-element is not enough are studied as well.

    The principle of antenna parallelism is demonstrated using both microstrip patch antennas and inverted-F antennas. Several techniques to combine the antennas in parallel have been evaluated. Firstly, a solution using power-splitters to form sub-arrays that covers one 500-MHz multi-band orthogonal frequency division multiplexing (OFDM) UWB is shown in Paper I. It is then proposed that the sub-bands are selected with a switching network. A more convenient method is to use the later developed frequency multiplexing technique as described in Paper V and VIII. Using the frequency multiplexing technique, selective connection of any number of antennas to a common junction is possible. The characteristic impedance is chosen freely, typically using a 50-Ω feed-line. Secondly, in Paper VIII a frequency-triplexed inverted-F antenna system is investigated to cover the Mode 1 multi-band UWB bandwidth 3.1-4.8 GHz. The antenna system is composed of three inverted-F antennas and a frequency triplexer including three 5th order bandpass filters. In Paper VI a printed circuit board integrated-triplexer for multi-band UWB radio is presented. The triplexer utilizes a microstrip network and three combined broadside- and edge-coupled filters. The triplexer is fully integrated in a four metal-layer printed circuit board with the minimum requirement on process tolerances. Furthermore, the system is built completely with distributed microstrips, i.e., no discrete components. Using the proposed solution an equal performance between the sub-bands is obtained. Finally suitable monopoles and dipoles are discussed and evaluated for UWB. In Paper X circular monopole and dipole antennas for UWB utilizing the flex-rigid concept are proposed. The flex-rigid concept combines flexible polyimide materials with the regular printed circuit board material. The antennas are placed entirely on the flexible part while the antenna ground plane and the dipole antenna balun are placed in the rigid part.

    List of papers
    1. Wideband patch antenna array for multi-band UWB
    Open this publication in new window or tab >>Wideband patch antenna array for multi-band UWB
    2004 (English)In: Proc. IEEE 11th Symp. on Communications and Vehicular Tech., Ghent, Belgium, November, 2004Conference paper, Published paper (Refereed)
    Abstract [en]

    As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, ultra wideband radio (UWB) will utilize the frequency-band of 3.1-10.6 GHz. Microstrip patch antennas have advantages of low cost and compatibility to the printed circuit board (PCB) technology, having the possibility to integrate the antenna with the circuit board. Since patch antennas have ground planes, components can be placed on the other side of the PCB, this allows a compact module design. However, the microstrip patch antenna has drawback of small bandwidth. Bandwidth is limited since the substrate height is limited. To overcome these drawbacks, we have studied a method to use a patch array with varied patch lengths on a low loss PCB. Patches electrically far away from each other will give independent resonances. By choosing several patch lengths so that the standing wave ratio (SWR) plots of the antennas overlap, they can be combined into one wideband with a power-divider. Several arrays can be combined to a multi-band antenna system using switches. A patch antenna array for the multiband UWB in the frequency band of 3.1-10.6 GHz is presented in this paper.

    Keywords
    Ultra wideband, UWB, patch antenna, wireless, antenna array
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12793 (URN)
    Conference
    IEEE 11th Symp. on Communications and Vehicular Tech., Ghent, Belgium, November
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    2. An integrated spiral antenna system for UWB
    Open this publication in new window or tab >>An integrated spiral antenna system for UWB
    2005 (English)In: Proc. IEEE 35th European Microwave Conference, 4-6 October, Paris, France, 2005, p. 2007-2010Conference paper, Published paper (Refereed)
    Abstract [en]

    As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz. The spiral antenna has a higher spectral efficiency than other planar antennas like the patch antenna. Theoretically, any type of antennas can be combined into different kind of arrays, in order to improve performance beyond that from one single antenna. The electrically coupled parallelism is one solution to extend bandwidth. By combining two spiral antennas with different radius of the radiation zone, the standing wave ratio (SWR) can be kept low for a large bandwidth, resulting in an improved spiral antenna performance for UWB. Furthermore, a study of how spiral dimensions impact on gain and SWR was conducted and presented.

    Keywords
    uwb, antenna, ultra wideband radio, spiral antenna
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12794 (URN)10.1109/EUMC.2005.1610362 (DOI)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    3. Monofilar spiral antennas for UWB with and without air core
    Open this publication in new window or tab >>Monofilar spiral antennas for UWB with and without air core
    2007 (English)In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 2, no 1, p. 64-70Article in journal (Refereed) Published
    Abstract [en]

    One of the trends in wireless communicationis that systems require more and more frequency spectrum.Consequently, the demand for wideband antennas increasesas well. For instance, the ultra wideband radio (UWB)utilizes the frequency band of 3.1-10.6 GHz. Such abandwidth is more than what is normally utilized with asingle low-profile antenna. Low profile antennas arepopular because they are integratable on a printed circuitboard. However, the fractional bandwidth is usually anissue for low profile antennas because of the limitedsubstrate height. The monofilar spiral antenna on the otherhand has higher fractional bandwidth, and at GHzfrequencies the physical dimensions of the spiral isreasonable. Furthermore, a study of how spiral dimensionsimpact on antenna gain and standing wave ratio (SWR) wasconducted and presented. Simulated results were comparedwith measurements.

    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-12795 (URN)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    4. Air core patch antennas suitable for multi-band UWB
    Open this publication in new window or tab >>Air core patch antennas suitable for multi-band UWB
    2005 (English)In: Proc. GigaHertz 2005, Uppsala, Sweden, 2005, p. 218-221Conference paper, Published paper (Refereed)
    Abstract [en]

    As wireless communication applications grow rapidly, the demand for modular solutions with high performance and low profile antennas increases. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz. Integrateable antennas should be of planar structures. A Planar structure limits design options, regarding various performance aspects. For instance, the spectral efficiency, i.e., the bandwidth (BW) relative to the center frequency (CF) is limited. The antenna efficiency, i.e., gain relative to directivity is also limited. The antenna efficiency is important for receiver sensitivity, which is important in UWB systems. The efficiency is dependant of the antenna structure and material used. The Rogers 4350B material is suitable for high frequency modules since it has a low loss tangent that is stable over a wide frequency range, but the substrate height is limited. In this study a printed circuit board (PCB) with an air core was introduced to increase the antenna efficiency. The module is processed as two separate double-layer PCBs. This technique can be implemented to increase the performance in a narrowband as well as in a wideband antenna system. An advantage is that components can be placed on the other side of the ground plane without interference since the ground plane shields components from antenna radiation. A study of how the antenna bandwidth and efficiency are improved with the proposed structure at 3.5 and 10 GHz was conducted and presented.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12796 (URN)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    5. Frequency-multiplexed Inverted-F Antennas for Multi-band UWB
    Open this publication in new window or tab >>Frequency-multiplexed Inverted-F Antennas for Multi-band UWB
    2006 (English)In: IEEE Annual Wireless and Microwave Technology Conference WAMICON '06, 2006, p. FF-2-1--FF-2-3Conference paper, Published paper (Refereed)
    Abstract [en]

    An invented frequency multiplexing technique is used to combine inverted-F antennas for multi-band UWB. The frequency multiplexing technique allows a number of independent antennas to be used in parallel. In this paper a radio front-end system consisting of three antennas and a frequency multiplexing network is built. Using one antenna for each sub-band within a band-group provides equal performance for the entire band. Both the antennas and the frequency multiplexing network can be integrated on a printed circuit board. The antennas were simulated and measured. S-parameters of the antennas were extracted and used for co-simulation with the frequency multiplexing network. The antenna system fulfills the requirement for Mode 1 UWB.

    Keywords
    UWB antenna, Frequency multiplexing, Inverted-F antenna
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12797 (URN)10.1109/WAMICON.2006.351944 (DOI)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    6. All-Microstrip Design of Three Multiplexed Antennas and LNA for UWB Systems
    Open this publication in new window or tab >>All-Microstrip Design of Three Multiplexed Antennas and LNA for UWB Systems
    2006 (English)In: Asia-Pacific Microwave Conf., December 2006, 2006, p. 1106-1109Conference paper, Published paper (Refereed)
    Abstract [en]

    An ultra-wideband (UWB) 3.1-4.8 GHz radio front-end consisting of three frequency multiplexed antennas and a low-noise amplifier (LNA) is presented in this paper. Using one antenna for each sub-band and an LNA designed for maximum-flat power gain provides equal performance within the entire frequency band. Frequency multiplexing is used to combine the antennas for multi-band UWB. The LNA is optimized for wideband operation and minimum noise figure. The LNA design employs dual-section input and output matching networks. The antennas, the frequency multiplexing network, the matching networks and the bias circuit of the LNA are all implemented using microstrip lines.

    Keywords
    antenna arrays, frequency division multiplexing, low noise amplifiers, microstrip antennas, microwave amplifiers, microwave antennas, ultra wideband antennas, wideband amplifiers, LNA, UWB systems, bias circuit, dual-section matching networks, frequency 3.1 GHz to 4.8 GHz, frequency multiplexed antennas, microstrip design, microstrip lines, multiband UWB, ultra-wideband radio front-end
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12798 (URN)10.1109/APMC.2006.4429602 (DOI)978-4-902339-08-6 (ISBN)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17Bibliographically approved
    7. A Frequency Triplexer for Ultra-wideband Systems Utilizing Combined Broadside- and Edge-coupled Filters
    Open this publication in new window or tab >>A Frequency Triplexer for Ultra-wideband Systems Utilizing Combined Broadside- and Edge-coupled Filters
    2008 (English)In: IEEE Transactions on Advanced Packaging, ISSN 1521-3323, E-ISSN 1557-9980, Vol. 31, no 4, p. 794-801Article in journal (Refereed) Published
    Abstract [en]

    A fully integrated triplexer for multiband ultra-wideband radio is presented. The triplexer utilizes a microstrip network and three combined broadside- and edge-coupled filters. It is fully integrated in a printed circuit board with low requirements on the printed circuit board process tolerance. Three flat subbands in the frequency band 3.1-4.8 GHz have been achieved. The group delay variation within each 500-MHz subband was measured to be around 1 ns. A good agreement between simulation and measurement was obtained.

    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-12799 (URN)10.1109/TADVP.2008.2004415 (DOI)
    Projects
    microstrip components, multiplexing equipment , ultra wideband communication
    Note
    ©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Magnus Karlsson, Pär Håkansson and Shaofang Gong, A Frequency Triplexer for Ultra-wideband Systems Utilizing Combined Broadside- and Edge-coupled Filters, 2008, IEEE Transactions on Advanced Packaging, (31), 4, 794-801. http://dx.doi.org/10.1109/TADVP.2008.2004415 Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    8. A Frequency-Triplexed Inverted-F Antenna System for Ultra-wide Multi-band Systems 3.1-4.8 GHz
    Open this publication in new window or tab >>A Frequency-Triplexed Inverted-F Antenna System for Ultra-wide Multi-band Systems 3.1-4.8 GHz
    2007 (English)In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 1, no 1, p. 95-100Article in journal (Refereed) Published
    Abstract [en]

    A fully integrated triplex antenna system for multibandUWB 3.1-4.8 GHz is presented. The system utilizes amicrostrip network and three combined broadside- and edgecoupledfilters to connect three inverted-F antennas in parallel.The triplexd antenna system is fully integrated in a printedcircuit board with low requirements on the printed circuit boardprocess tolerance. The group delay variation within the triplexerwas measured to be less than 1 ns. Furthermore, a goodagreement between simulation and measurement results wasobserved.

    Keywords
    Bandpass filter, Broadside coupled, Edge coupled, Frequency multiplexing, Inverted-F antenna, Triplexer, UWB
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-12800 (URN)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
    9. Microstrip Bias Networks for Ultra-Wideband Systems
    Open this publication in new window or tab >>Microstrip Bias Networks for Ultra-Wideband Systems
    2008 (English)In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 1, no 2, p. 16-20Article in journal (Refereed) Published
    Abstract [en]

    Bias networks with radio frequency (RF) chokes can be implemented using different microstrip elements. They can have different advantages in terms of bandwidth and occupied area. However, sharp discontinuities of the transfer functions have been observed in these types of bias networks. In this paper they are explained by resonances generated within the DC path of the bias network. As the resonance behavior degrades the performance of broadband RF circuits, the robustness of different bias networks against resonance was investigated. Different bias networks were fabricated and measured. Both simulation and experimental results show that broadband microstrip bias networks can be optimized to avoid or reduce the resonance phenomena.

    Keywords
    Bias networks, microstrip components
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12801 (URN)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17Bibliographically approved
    10. A Frequency-triplexed RF Front-end for Ultra-wideband Systems 3.1-4.8 GHz
    Open this publication in new window or tab >>A Frequency-triplexed RF Front-end for Ultra-wideband Systems 3.1-4.8 GHz
    2008 (English)In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 1, no 2, p. 83-88Article in journal (Refereed) Published
    Abstract [en]

    A multi-band and ultra-wideband (UWB) 3.1-4.8 GHz receiver front-end consisting of a fully integrated filter and triplexer network, and a flat gain low-noise amplifier (LNA) is presented in this paper. The front-end utilizes a microstrip network and three combined broadside- and edge-coupled bandpass filters to connect the three sub-bands. The LNA design employs dual-section input and output microstrip matching networks for wideband operation with a flat power gain and a low noise figure. The system is fully integrated in a four-metal-layer printed circuit board. The measured power gain is 10 dB and the noise figure of the front-end is 6 dB at each center frequency of the three sub-bands. The minimum isolation between the sub-bands is -27 dB and the isolation between the non-neighboring alternate sub-bands is -52 dB. The out-of-band interferer attenuation is below -30 dB.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12802 (URN)
    Note
    The status of this article was previously Submitted.Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17Bibliographically approved
    11. Mono- and Di-pole Antennas for UWB Utilizing Flex-rigid Technology
    Open this publication in new window or tab >>Mono- and Di-pole Antennas for UWB Utilizing Flex-rigid Technology
    2007 (English)In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 2, no 1, p. 59-63Article in journal (Refereed) Published
    Abstract [en]

    Fully integrated monopole and dipole antennas forultra-wideband (UWB) radio utilizing flexible and rigid printedcircuit boards are presented in this paper. A circular monopoleantenna for the entire UWB frequency band 3.1-10.6 GHz ispresented. A circular dipole antenna with an integrated balun forthe frequency band 3.1-4.8 GHz is also presented. The balunutilizes broadside-coupled microstrips, integrated in the rigidpart of the printed circuit board. Furthermore, anomnidirectional radiation pattern and high radiation efficiencyare predicted by simulations.

    Keywords
    Broadside-coupled, circular, dipole antenna, monopole antenna, UWB
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-12803 (URN)
    Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2019-06-17
  • 12.
    Karlsson, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    UWB for wireless high-speed data transmission2007In: Sveriges Energiting 2007,2007, 2007Conference paper (Other academic)
    Abstract [en]

    Kommunikation är en naturlig del av vardagen i det moderna samhället. Allt eftersom nya behov dyker upp så ökar kravet på effektivitet och kapacitet i systemen. Fler och fler system som dock ofta är inkompatibla med varandra har varit en klar trend de senaste åren. Intresset ökar dock för att samordna dem för att spara både energi och material. Konsekvensen blir krav på strömsnål elektronik som samtidigt förväntas att klara allt mer. -Ultra-wideband radio- (UWB, sv. Ultra-bredbandsradio) är en relativt ny lovande strömsnål teknologi för att möta dessa krav. Det kan låta motsägelsefullt med bredbandiga signaler och låg strömförbrukning. Genom att just sprida ut signalen över ett brett frekvensområde så kan väldigt svaga signaler användas, signalstyrkan som används ligger under det naturliga brusgolvet. Hemmen fylls allt mer av modern elektronik, allt från CD, DVD med mera. Ofta är det dessutom inte nog med en av varje för att man vill kunna titta på favoritfilmen både i vardagsrummet och i sovrummet. Med UWB kan uppgifter samordnas och en mediacentral kan förse flera användare, på så sätt minskar man antalet maskiner som ständigt står och går. Förutom strömmande media applikationer kan man exempelvis överföra data mellan sin bärbara och sin stationära dator. Alla kortdistansdataöverföringar som idag görs med kabel eller någon annan trådlös teknik kan istället ersättas med UWB. Gruppnamnet för den här typen av tjänster är -Wireless personal area network- (WPAN, sv. trådlöst personligt nätverk). Bortsett från att lösa olika överföringsbehov så kan UWB användas till -imaging- system, som kan liknas med högupplöst radar. Ett tredje intressant användningsområde är sensorer. Höghastighetssystem som UWB förknippas sällan med sensornätverk men tekniken är strömsnål och datamängden är lätt att skala ner så att övriga komponenter inte kräver för mycket ström. Aktiva RFID (radiofrekvensidentifikation) brickor är ett ytterligare användningsområde. Nyckeln för den breda användbarheten är låg strömförbrukning per överförd information i kombination med skalbarhet. Detta sammantaget resulterar i att UWB kan designas för att med bibehållet höga krav på låg energiförbrukning väl kan möta många informationstekniska behov.

  • 13.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Air core patch antennas suitable for multi-band UWB2005In: Proc. GigaHertz 2005, Uppsala, Sweden, 2005, p. 218-221Conference paper (Refereed)
    Abstract [en]

    As wireless communication applications grow rapidly, the demand for modular solutions with high performance and low profile antennas increases. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz. Integrateable antennas should be of planar structures. A Planar structure limits design options, regarding various performance aspects. For instance, the spectral efficiency, i.e., the bandwidth (BW) relative to the center frequency (CF) is limited. The antenna efficiency, i.e., gain relative to directivity is also limited. The antenna efficiency is important for receiver sensitivity, which is important in UWB systems. The efficiency is dependant of the antenna structure and material used. The Rogers 4350B material is suitable for high frequency modules since it has a low loss tangent that is stable over a wide frequency range, but the substrate height is limited. In this study a printed circuit board (PCB) with an air core was introduced to increase the antenna efficiency. The module is processed as two separate double-layer PCBs. This technique can be implemented to increase the performance in a narrowband as well as in a wideband antenna system. An advantage is that components can be placed on the other side of the ground plane without interference since the ground plane shields components from antenna radiation. A study of how the antenna bandwidth and efficiency are improved with the proposed structure at 3.5 and 10 GHz was conducted and presented.

  • 14.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Carlsson, Hakan
    Combitech AB, Sweden.
    Idebro, Mats
    Combitech AB, Sweden.
    Eek, Christoffer
    Combitech AB, Sweden.
    Microwave Heating as a Method to Improve Sanitation of Sewage Sludge in Wastewater Plants2019In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 142308-142316Article in journal (Refereed)
    Abstract [en]

    For long-term sustainable agriculture, it is critical that we recycle nutrition to the soil that it came from. One important source is sewage sludge, but it must be sanitized from undesired pathogens before it may be spread on arable land. One common method today is deposition in about six months or more. Not only is such a long deposition-time costly due to the required storage-space, in the future usage of the method is likely to be more restricted from a regulatory perspective. To heat up sewage-sludge is a known method to speed up the sanitation process. However, achieving an even guaranteed temperature is not easy with porous sewage sludge. This is mainly due to the limited heat conductivity of the sludge. Microwaves at a frequency of 2.45 GHz have a penetration depth of a few centimeters and therefore has an advantage compared to other heating methods which only heats the surface. In the proposed system, the sewage sludge is continuously processed through a series of microwave cavities. The pathogen removal effectiveness was studied for different exposure settings, e.g., conveyor speed and applied microwave power in each cavity.

  • 15.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A Frequency-Triplexed Inverted-F Antenna System for Ultra-wide Multi-band Systems 3.1-4.8 GHz2007In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 1, no 1, p. 95-100Article in journal (Refereed)
    Abstract [en]

    A fully integrated triplex antenna system for multibandUWB 3.1-4.8 GHz is presented. The system utilizes amicrostrip network and three combined broadside- and edgecoupledfilters to connect three inverted-F antennas in parallel.The triplexd antenna system is fully integrated in a printedcircuit board with low requirements on the printed circuit boardprocess tolerance. The group delay variation within the triplexerwas measured to be less than 1 ns. Furthermore, a goodagreement between simulation and measurement results wasobserved.

  • 16.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    An integrated spiral antenna system for UWB2005In: Proc. IEEE 35th European Microwave Conference, 4-6 October, Paris, France, 2005, p. 2007-2010Conference paper (Refereed)
    Abstract [en]

    As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz. The spiral antenna has a higher spectral efficiency than other planar antennas like the patch antenna. Theoretically, any type of antennas can be combined into different kind of arrays, in order to improve performance beyond that from one single antenna. The electrically coupled parallelism is one solution to extend bandwidth. By combining two spiral antennas with different radius of the radiation zone, the standing wave ratio (SWR) can be kept low for a large bandwidth, resulting in an improved spiral antenna performance for UWB. Furthermore, a study of how spiral dimensions impact on gain and SWR was conducted and presented.

  • 17.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Circular Dipole Antenna for Mode 1 UWB Radio With Integrated Balun Utilizing a Flex-Rigid Structure2009In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 57, no 10, p. 2967-2971Article in journal (Refereed)
    Abstract [en]

    Abstract—Afully integrated dipole antenna with balun for ultra-wideband (UWB) radio utilizing a flexible and rigid printed circuit board is presented in this paper. The concept in this paper is to take advantage of the respective possibilities of the rigid and flex-ible parts. The balun utilizes broadside-coupled microstrips and is integrated in the rigid part of the printed circuit board, whereas the radiator is placed in the flexible part. The antenna with thebalun covers the mode 1 UWB frequency-band 3.1–4.8 GHz (with margin) at voltage standing wave ratio (VSWR) < 2. Further-more, good radiation characteristics and a linear phase responseare observed with measurements.

  • 18.
    Karlsson, Magnus
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Gong, Shaofang
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Circular Monopole and Dipole Antennas for UWB Radio Utilizing a Flex-rigid Structure2008In: GHz 2008,2008, 2008, p. 75-75Conference paper (Other academic)
    Abstract [en]

      

  • 19.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Mono- and Di-pole Antennas for UWB Utilizing Flex-rigid Technology2007In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 2, no 1, p. 59-63Article in journal (Refereed)
    Abstract [en]

    Fully integrated monopole and dipole antennas forultra-wideband (UWB) radio utilizing flexible and rigid printedcircuit boards are presented in this paper. A circular monopoleantenna for the entire UWB frequency band 3.1-10.6 GHz ispresented. A circular dipole antenna with an integrated balun forthe frequency band 3.1-4.8 GHz is also presented. The balunutilizes broadside-coupled microstrips, integrated in the rigidpart of the printed circuit board. Furthermore, anomnidirectional radiation pattern and high radiation efficiencyare predicted by simulations.

  • 20.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Monofilar spiral antennas for UWB with and without air core2007In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 2, no 1, p. 64-70Article in journal (Refereed)
    Abstract [en]

    One of the trends in wireless communicationis that systems require more and more frequency spectrum.Consequently, the demand for wideband antennas increasesas well. For instance, the ultra wideband radio (UWB)utilizes the frequency band of 3.1-10.6 GHz. Such abandwidth is more than what is normally utilized with asingle low-profile antenna. Low profile antennas arepopular because they are integratable on a printed circuitboard. However, the fractional bandwidth is usually anissue for low profile antennas because of the limitedsubstrate height. The monofilar spiral antenna on the otherhand has higher fractional bandwidth, and at GHzfrequencies the physical dimensions of the spiral isreasonable. Furthermore, a study of how spiral dimensionsimpact on antenna gain and standing wave ratio (SWR) wasconducted and presented. Simulated results were comparedwith measurements.

  • 21.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Wideband patch antenna array for multi-band UWB2004In: Proc. IEEE 11th Symp. on Communications and Vehicular Tech., Ghent, Belgium, November, 2004Conference paper (Refereed)
    Abstract [en]

    As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, ultra wideband radio (UWB) will utilize the frequency-band of 3.1-10.6 GHz. Microstrip patch antennas have advantages of low cost and compatibility to the printed circuit board (PCB) technology, having the possibility to integrate the antenna with the circuit board. Since patch antennas have ground planes, components can be placed on the other side of the PCB, this allows a compact module design. However, the microstrip patch antenna has drawback of small bandwidth. Bandwidth is limited since the substrate height is limited. To overcome these drawbacks, we have studied a method to use a patch array with varied patch lengths on a low loss PCB. Patches electrically far away from each other will give independent resonances. By choosing several patch lengths so that the standing wave ratio (SWR) plots of the antennas overlap, they can be combined into one wideband with a power-divider. Several arrays can be combined to a multi-band antenna system using switches. A patch antenna array for the multiband UWB in the frequency band of 3.1-10.6 GHz is presented in this paper.

  • 22.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Huynh, Allan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Parallel channels using frequency multiplexing techniques2010In: Ultra Wideband / [ed] Boris Lembrikov, SCIYO , 2010, p. 35-54Chapter in book (Other academic)
    Abstract [en]

    Ultra wideband technology is one of the most promising directions in the rapidly developing modern communications. Ultra wideband communication system applications include radars, wireless personal area networks, sensor networks, imaging systems and high precision positioning systems. Ultra wideband transmission is characterized by high data rate, availability of low-cost transceivers, low transmit power and low interference. The proposed book consisting of 19 chapters presents both the state-of-the-art and the latest achievements in ultra wideband communication system performance, design and components. The book is addressed to engineers and researchers who are interested in the wide range of topics related to ultra wideband communications.

  • 23.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Håkansson, Pär
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A Frequency Triplexer for Ultra-wideband Systems Utilizing Combined Broadside- and Edge-coupled Filters2008In: IEEE Transactions on Advanced Packaging, ISSN 1521-3323, E-ISSN 1557-9980, Vol. 31, no 4, p. 794-801Article in journal (Refereed)
    Abstract [en]

    A fully integrated triplexer for multiband ultra-wideband radio is presented. The triplexer utilizes a microstrip network and three combined broadside- and edge-coupled filters. It is fully integrated in a printed circuit board with low requirements on the printed circuit board process tolerance. Three flat subbands in the frequency band 3.1-4.8 GHz have been achieved. The group delay variation within each 500-MHz subband was measured to be around 1 ns. A good agreement between simulation and measurement was obtained.

  • 24.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Håkansson, Pär
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Huynh, Allan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Frequency-multiplexed Inverted-F Antennas for Multi-band UWB2006In: IEEE Annual Wireless and Microwave Technology Conference WAMICON '06, 2006, p. FF-2-1--FF-2-3Conference paper (Refereed)
    Abstract [en]

    An invented frequency multiplexing technique is used to combine inverted-F antennas for multi-band UWB. The frequency multiplexing technique allows a number of independent antennas to be used in parallel. In this paper a radio front-end system consisting of three antennas and a frequency multiplexing network is built. Using one antenna for each sub-band within a band-group provides equal performance for the entire band. Both the antennas and the frequency multiplexing network can be integrated on a printed circuit board. The antennas were simulated and measured. S-parameters of the antennas were extracted and used for co-simulation with the frequency multiplexing network. The antenna system fulfills the requirement for Mode 1 UWB.

  • 25.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Owais, Owais
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Physics and Electronics.
    Jobs, Magnus
    Uppsala University.
    Gruden, Mathias
    Uppsala University.
    Dipole Antenna With Integrated Balun For Ultra-wideband Radio 6-9 GHz2011In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 53, no 1, p. 180-184Article in journal (Refereed)
    Abstract [en]

    A fully integrated dipole antenna with a balun fot ulna wideband (UWB) radio in the band 6-9 GHz utilizing a flexible and rigid printed count board is presented in this at tide The balun utilizes broadside coupled microstrips and is integrated in the rigid part of the printed coma boat d whereas the radiator is placed in the flexible pat! The antenna with the balun covets the frequency band 6 0-8 5 GHz at voltage standing mate ratio (VSWR) andlt;2 0 and 55-110 GHz at VSWR andlt; 2 5 Moreover simulated and measured radiation patterns and antenna efficiency above 860% are observed

  • 26.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Owais, Owais
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Frequency Triplexer for Ultra-Wideband Systems (6–9 GHz)2013In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 60, no 3, p. 540-547Article in journal (Refereed)
    Abstract [en]

    A triplexer for ultra-wideband radio implemented entirely with distributed microstrips is presented. The triplexer is composed of a triplex junction network and three bandpass filters. The circuit is integrated in a flex-rigid printed circuit board. Three flat 1 GHz sub-bands in the frequency band 6-9 GHz have been achieved. The group delay variation within each 1 GHz sub-band was measured to be less than 0.4 ns. A good agreement between simulation and measurement was obtained, e.g., less than 0.3 dB difference in the forward transmission in the majority of the frequency band.

  • 27.
    Karlsson, Magnus
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Serban Craciunescu, Adriana
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    UWB för trådlös och hög hastighetsdata överföring2006In: Energi, IT och Design,2006, 2006, p. 24-24Conference paper (Other academic)
    Abstract [sv]

    Trådlös kommunikation är en del av vardagen i det moderna samhället. Allt eftersom nya behov dyker upp så ökar kravet på effektivitet och kapacitet i systemen. Fler system som dock ofta är inkompatibla med varandra har varit en klar trend de senaste åren. Intresset ökar för att samordna dem för att spara både energi och material. Konsekvensen blir krav på strömsnål elektronik som samtidigt förväntas att klara allt mer. -Ultra-wideband radio- (UWB, sv. bredbandig radio) är en ny lovande strömsnål teknologi för att möta dessa krav. Det kan låta motsägelsefullt med bredbandiga signaler och låg strömförbrukning. Genom att just sprida ut signalen över ett brett frekvensområde så kan väldigt svaga signaler användas, signalstyrkan som används ligger under det naturliga brusgolvet. Informationen skickas som korta pulser utan bärvåg. Hemmen fylls allt mer av modern elektronik, allt från CD, DVD med mera. Ofta är det dessutom inte nog med en av varje för att man vill kunna titta på favoritfilmen både i vardagsrummet och i sovrummet. Med UWB kan uppgifter samordnas och en mediacentral kan förse flera användare, på så sätt minskar man antalet maskiner som förbrukar energi. Förutom strömmande media applikationer kan man exempelvis överföra data mellan sin bärbara och sin stationära dator. Alla kortdistansdataöverföringar som idag görs med kabel eller någon annan trådlös teknik kan istället ersättas med UWB. Gruppnamnet för den här typen av tjänster är -Wireless personal area network- (WPAN, sv. trådlöst personligt nätverk). Bortsett från att lösa olika överföringsbehov så kan UWB användas till -imaging- system, som kan liknas med högupplöst radar. Skillnaden mot klassisk lågupplöst radar är att man får information om objektet ifråga och inte bara uppgift om att det finns något i en viss riktning. Ett tredje intressant användningsområde är sensorer. Höghastighetssystem som UWB förknippas sällan med sensornätverk men tekniken är strömsnål och datamängden är lätt att skala ner så att övriga komponenter inte kräver för mycket ström. Aktiva RFID (radiofrekvensidentifikation) brickor är ett ytterligare användningsområde. Nyckeln för den breda användbarheten är låg strömförbrukning per verförd information i kombination med skalbarhet. Detta sammantaget resulterar i att UWB kan designas för att med bibehållet höga krav på låg energiförbrukning väl kan möta många informationstekniska behov.

  • 28.
    Karlsson, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Circular Dipole Antennas for Lower and Upper UWB Bands with Integrated Balun2009In: 2009 IEEEInternational Conference on Ultra-Wideband: Proceedings, 9th to 11th September 2009, Vancouver, BC, Canada, Vancover: IEEE , 2009, p. 658-663Conference paper (Refereed)
    Abstract [en]

    Abstract—Two fully integrated dipole antennas with balun for ultra-wideband (UWB) radio utilizing a flexible and rigid printed circuit board are presented in this paper. The concept in this paper is to take advantage of the respective possibilities of the rigid and the flexible part. The balun utilizes broadside-coupled microstrips and is integrated in the rigid part of the printed circuit board, while the radiator is placed in the flexible part. The lower UWB band antenna with the balun covers the frequency-band 3.1-4.8 GHz (with margin) at VSWR<2.0. The upper UWB band antenna with the balun covers the frequency-band 6.0-8.5 GHz (with margin) at VSWR<2.0, and 5.5-11.0 GHz at VSWR<2.5.

  • 29.
    Liu, Yu
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Hassan, Kahin Akram
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Karlsson, Magnus
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    Pang, Zhibo
    Corporate Research, ABB AB, Västerås, Sweden.
    Gong, Shaofang
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    A Data-Centric Internet of Things Framework Based on Azure Cloud2019In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 53839-53858Article in journal (Refereed)
    Abstract [en]

    Internet of Things (IoT) has been found pervasive use cases and become a driving force to constitute a digital society. The ultimate goal of IoT is data and the intelligence generated from data. With the progress in public cloud computing technologies, more and more data can be stored, processed and analyzed in cloud to release the power of IoT. However, due to the heterogeneity of hardware and communication protocols in the IoT world, the interoperability and compatibility among different link layer protocols, sub-systems, and back-end services have become a significant challenge to IoT practices. This challenge cannot be addressed by public cloud suppliers since their efforts are mainly put into software and platform services but can hardly be extended to end devices. In this paper, we propose a data-centric IoT framework that incorporates three promising protocols with fundamental security schemes, i.e., WiFi, Thread, and LoRaWAN, to cater to massive IoT and broadband IoT use cases in local, personal, and wide area networks. By taking advantages of the Azure cloud infrastructure, the framework features a unified device management model and data model to conquer the interoperability challenge. We also provide implementation and a case study to validate the framework for practical applications.

  • 30.
    Liu, Yu
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Hassan, Kahin Akram
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Weister, Ola
    Vertical Plants System Sweden AB, Norrrköping, Sweden.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Active Plant Wall for Green Indoor Climate Based on Cloud and Internet of Things2018In: IEEE Access, E-ISSN 2169-3536, Vol. 6, p. 33631-33644Article in journal (Refereed)
    Abstract [en]

    An indoor climate is closely related to human health, well-being and comfort. Thus, indoor climate monitoring and management are prevalent in many places, from public offices to residential houses. Our previous research has shown that an active plant wall system can effectively reduce the concentrations of particulate matter and volatile organic compounds and stabilize the carbon dioxide concentration in an indoor environment. However, regular plant care is restricted by geography and can be costly in terms of time and money, which poses a significant challenge to the widespread deployment of plant walls. In this article, we propose a remote monitoring and control system that is specific to the plant walls. The system utilizes the Internet of Things technology and the Azure public cloud platform to automate the management procedure, improve the scalability, enhance user experiences of plant walls, and contribute to a green indoor climate.

  • 31.
    Mahmood, Faraz
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Kazim, Jalil-ur-Rehman
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Ying, Zhinong
    CTO office Sony Ericsson Mobile Communications AB, Sweden.
    Decoupling techniques of compact and broadband MIMO antennas for handheld devices2012In: IEEE 6th European Conference on Antennas and propagation (EuCAP 2012), 2012, p. 1-5, article id 1569525515Conference paper (Refereed)
    Abstract [en]

    This paper presents an innovative MIMO antenna system consisting of two broadband antennas combined with a 90° or 180° hybrid coupler. The antenna system is suitable for future MIMO systems due to its wide decoupled bandwidth (from 698 to 2700 MHz) covering 23 frequency bands of LTE. Enhanced antenna performance is achieved by radiator slitting and ground plane modification. Moreover, supplemental meandered line ground structures are utilized to miniaturize the antenna size. The low profile antenna with its wide impedance bandwidth, high efficiency, low correlation and quasi-omni directional radiation pattern is attractive for the existing and future 4G mobile communication devices. Simulated and measured results including input reflection, mutual coupling, correlation, and antenna efficiency is presented and analyzed.

  • 32.
    Mohsin, Imran
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Frequency diplexer network for wireless parallel data transmission and ultrawideband systems utilizing manifold technique2014In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 56, no 8, p. 1869-1871Article in journal (Refereed)
    Abstract [en]

    A frequency diplexer network for ultrawideband radios focused on wireless parallel data transmission is presented. It has a combination of two bandpass filters utilizing manifold multiplexing technique. In the frequency band 6-9 GHz, two flat sub-bands at center frequencies 6.7 and 8.3 GHz have been achieved with respect to forward transmission, input reflection, and group delay. A maximum group delay variation of 0.6 ns was measured in the sub-bands. For low cost and simple circuit implementation, the design is implemented using the microstrip technology.

  • 33.
    Mohsin, Imran
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Owais, Owais
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Design and implementation of a UWB six-port correlator for 6-9 GHz frequency band2013In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 55, no 1, p. 190-193Article in journal (Refereed)
    Abstract [en]

    A compact size six-port correlator using bandwidth enhancing stubs for the 69 GHz ultra wideband radio is presented. The proposed six-port has a center frequency of 7.5 GHz with 50% relative bandwidth. The correlator is based entirely on microstrip technology for low cost and simple circuit implementation.

  • 34.
    Owais, Owais
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Circular Monopole Antenna Stability with Regard to Ground Plane Size2008In: Proc. of the 2008 International Symposium on Antenna and Propagation (ISAP'08), Taiwan, Oct. 27-30, 2008., 2008, p. 1-4, article id 1645003Conference paper (Refereed)
    Abstract [en]

    Wireless communications for short range and high data rate require wideband operation that necessitates the demand for miniaturized, low cost and low profile antennas. Miniaturized planar monopole antennas provide wide impedance bandwidth for wireless personal area network applications [1]. Different monopole shapes have been considered and a lot of research has been made to improve the bandwidth and reduce the size by changing the antenna shape [2]-[4]. The radiator part has been the main focus of research to find a shape that provides wide bandwidth [3]-[4], as well on studying how the ground plane affects the bandwidth of antennas. Wide bandwidth has been obtained by bevelling the radiator [5] and use of a modified ground plane [6]. Planar monopoles with parasitic elements and slots give also a wideband [7]. It has been documented that the finite size of the ground plane is an important factor for the antenna performance [8]. Planar monopoles have a benefit of being low cost and compatible to printed circuit board (PCB) allowing compact design. Since the ground plane is coplanar with the antenna, it necessitates that its stability should not change when integrated in PCB with different ground plane size of adjoining circuits. To avoid pre-tuning and achieve cost effectiveness, system development requires a stable planar monopole antenna that can be integrated without depreciation of its performance. This paper studies in detail the effect of ground plane dimension, width and length, on the stability of the coplanar monopole antenna, by changing the ground plane size while keeping feedline and feedap constant. The parametric investigation supported by simulation and experimental results is conducted in this paper to give insights to the stability issue that have not been reported before.

  • 35.
    Owais, Owais
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ying, Zhinong
    Sony Ericsson Mobile Commun AB.
    Gruden, Mathias
    Sony Ericsson Mobile Commun AB.
    Job, Magnus
    Uppsala University.
    Wideband Planar Antenna with Modified Ground Plane2010In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 52, no 11, p. 2581-2585Article in journal (Refereed)
    Abstract [en]

    In this article a miniaturized planar antenna is presented for broadband applications. Antenna miniaturization is achieved by modifying the ground plane that creates a different current path thus increasing the effective dimension of the antenna. In addition, dual chopping, slitting, and radiator position offsetting provide wideband behavior and relatively good impedance matching. The low profile antenna with its wide bandwidth, linear phase response and quasi-omnidirectional radiation pattern is attractive for the existing and future communication devices of small size. Simulated and measured results for the proposed antenna are presented and analyzed.

  • 36.
    Owais, Owais
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Differential Six-Port Demodulator2011In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 53, no 9, p. 2192-2197Article in journal (Refereed)
    Abstract [en]

    A differential six-port demodulator for the 7-8 GHz band is reported for the first time. It is composed of a differential six-port correlator on the two sides of the substrate and zero-bias antiparallel Schottky diodes acting as power detectors. It is theoretically analyzed and also simulated. A prototype has been fabricated and data transmission at 0.8 Gbit/s (but not the maximum) with the 16 quadrature amplitude modulation (QAM) is experimentally demonstrated.

  • 37.
    Owais, Owais
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Differential Six-Port TransceiverManuscript (preprint) (Other academic)
    Abstract [en]

    A differential six-port transceiver for the 7-8 GHz band is presented for the rst time. It is fabricated using double-sided parallel-strip lines. The transmitter is composed of a differential six-port correlator with a quarter wavelength arrangement for carrier suppression. Cold-mode field effect transistors are used as impedance terminations, controlled via baseband signals on the gate to source terminal. The receiver is comprised of a differential six-port correlator and diode detectors. The diodes on the front-side and the back-side are connected in antiparallel, resulting in a differential input and differential output six-port receiver. The main features of the transceiver are low complexity, low power consumption, and high data rate. Data transmission and reception with the transceiver is demonstrated with quadrature phase shift keying (QPSK) and 16-quadrature amplitude modulation (16-QAM) with 100 and 200 M symbol / s , respectively.

  • 38.
    Serban, Adriana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A Frequency-triplexed RF Front-end for Ultra-wideband Systems 3.1-4.8 GHz2008In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 1, no 2, p. 83-88Article in journal (Refereed)
    Abstract [en]

    A multi-band and ultra-wideband (UWB) 3.1-4.8 GHz receiver front-end consisting of a fully integrated filter and triplexer network, and a flat gain low-noise amplifier (LNA) is presented in this paper. The front-end utilizes a microstrip network and three combined broadside- and edge-coupled bandpass filters to connect the three sub-bands. The LNA design employs dual-section input and output microstrip matching networks for wideband operation with a flat power gain and a low noise figure. The system is fully integrated in a four-metal-layer printed circuit board. The measured power gain is 10 dB and the noise figure of the front-end is 6 dB at each center frequency of the three sub-bands. The minimum isolation between the sub-bands is -27 dB and the isolation between the non-neighboring alternate sub-bands is -52 dB. The out-of-band interferer attenuation is below -30 dB.

  • 39.
    Serban, Adriana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Compontent Tolerance Effect on Ultra-Wideband Low-Noise Amplifier Performance2010In: IEEE Transactions on Advanced Packaging, ISSN 1521-3323, E-ISSN 1557-9980, Vol. 33, no 3, p. 660-668Article in journal (Refereed)
    Abstract [en]

    A study of the component tolerances on an ultra-wideband low-noise amplifier designed on a conventional printed circuit board is presented in this paper. The low-noise amplifier design employs dual-section input and output microstrip matching networks for wideband operation with a low noise figure and a flat power gain. Firstly, the effect of passive component and manufacturing process tolerances on the low-noise amplifier performance is theoretically studied by means of sensitivity analyses. Secondly, simulation and measurement results are presented for verification of the analytical results. It is shown that, compared with a lumped matching network design, a microstrip matching network design significantly reduces the ultra-wideband low-noise amplifier sensitivity to component tolerances.

  • 40.
    Serban, Adriana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Microstrip Bias Networks for Ultra-Wideband Systems2008In: ISAST Transactions on Electronics and Signal Processing, ISSN 1797-2329, Vol. 1, no 2, p. 16-20Article in journal (Refereed)
    Abstract [en]

    Bias networks with radio frequency (RF) chokes can be implemented using different microstrip elements. They can have different advantages in terms of bandwidth and occupied area. However, sharp discontinuities of the transfer functions have been observed in these types of bias networks. In this paper they are explained by resonances generated within the DC path of the bias network. As the resonance behavior degrades the performance of broadband RF circuits, the robustness of different bias networks against resonance was investigated. Different bias networks were fabricated and measured. Both simulation and experimental results show that broadband microstrip bias networks can be optimized to avoid or reduce the resonance phenomena.

  • 41.
    Serban, Adriana
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Owais, Owais
    COMSATS Institute of Information Technology, .
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Differential Circuit Technique for Six-Port Modulator and Demodulator2012In: Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International, IEEE , 2012, p. 1-3Conference paper (Refereed)
    Abstract [en]

    Targeting the differential RF/microwave circuit design methodology for improved broadband wireless data transmission, a novel differential 7.5 GHz six-port modulator and demodulator pair was designed and manufactured. Measurements show a good 256-QAM modulated signal at 50 Msymbol/s and an accurately 16-QAM demodulated signal at 200 Msymbol/s.

  • 42.
    Serban, Adriana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Owais, Owais
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Haartsen, Jaap
    Sony Ericsson Mobile Communications AB, Lund, Sweden.
    Karlsson, Peter
    Sony Ericsson Mobile Communications AB, Lund, Sweden.
    Six-Port Direct Carrier Modulator at 7.5 GHz for Ultra-Wideband  AppliationsManuscript (preprint) (Other academic)
    Abstract [en]

    A 7.5 GHz direct-carrier modulator for multi-level quadrature amplitude modulation (M-QAM) using a wideband 7-8 GHz six-port correlator and four controllable impedance terminations implemented with field-effect transistors (FET) is presented in this paper. The proposed encoding schemes of the reflection-type modulator is based on equal impedance values at I and Q ports, such that Γ3 = Γ4 and Γ5 = Γ6 for every symbol in the constellation diagram. The field-effect transistors are operated at zero drain-source voltage (cold-FET). The FET-impedance termination topology includes a source resistor (RS) and a gate resistor (RG) for symmetrical spreading of the reflection coefficients around the origin. In order to validate the 7.5 GHz six-port modulator with cold-FET impedance terminations, the six-port modulator prototype has been realized on a ROGERS4350B substrate of 0.254-mm thickness and tested with a six-port demodulator (receiver). The six-port modulator was measure to have symbol rates of 10 Msymbol/s with QPSK (= 20 Mbit/s) and 250 Msymbol/s with 16-QAM (= 1 Gbit/s).

  • 43.
    Serban, Adriana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Owais, Owais
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Haartsen, Jaap
    Sony Ericsson Mobile Communications AB, Lund, Sweden.
    Karlsson, Peter
    Sony Ericsson Mobile Communications AB, Lund, Sweden.
    Six-port transceiver for 6-9 GHz ultrawideband systems2010In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 42, no 3, p. 740-746Article in journal (Refereed)
    Abstract [en]

    An ultrawideband 6-9 GHz six-port correlator is designed and manufactured.Based on this six-port correlator, behavioral models, and true component circuit designs of a transceiver are developed to study the performance of the proposed direct conversion ultrawideband transceiver topology. A new six-port modulator with controllable impedance terminations implemented with a field effect transistor in the linear operation region is presented

  • 44.
    Serban (Craciunescu), Adriana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    All-Microstrip Design of Three Multiplexed Antennas and LNA for UWB Systems2006In: Asia-Pacific Microwave Conf., December 2006, 2006, p. 1106-1109Conference paper (Refereed)
    Abstract [en]

    An ultra-wideband (UWB) 3.1-4.8 GHz radio front-end consisting of three frequency multiplexed antennas and a low-noise amplifier (LNA) is presented in this paper. Using one antenna for each sub-band and an LNA designed for maximum-flat power gain provides equal performance within the entire frequency band. Frequency multiplexing is used to combine the antennas for multi-band UWB. The LNA is optimized for wideband operation and minimum noise figure. The LNA design employs dual-section input and output matching networks. The antennas, the frequency multiplexing network, the matching networks and the bias circuit of the LNA are all implemented using microstrip lines.

  • 45.
    Serban Craciunescu, Adriana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Study of bias networks with RF choke for ultra-wideband systemsManuscript (preprint) (Other academic)
    Abstract [en]

    In this letter, bias networks with three different radio frequency chokes for ultra-wideband systems have been studied. The bias network with a butterfly stub results in not only the broadest band, but also the highest robustness. Resonances generated within the DC path of the bias network are investigated and explained. Both simulation and experimental results show that microstrip bias networks for ultra-wideband systems can be optimized to avoid or reduce the resonance phenomena.

  • 46.
    Wu, Duolong
    et al.
    School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Highly Unequal Three-Port Power Divider: Theory and Implementation2018In: International Journal of Antennas and Propagation, ISSN 1687-5869, E-ISSN 1687-5877, article id 9141964Article in journal (Refereed)
    Abstract [en]

    A three-port power divider consisting of a directional coupler, a Wilkinson power divider, and two transmission lines connected to them is proposed. Theoretical analysis reveals that highly unequal power division can be achieved by a feedback mechanism of two transmission lines along with the coupling coefficient of the directional coupler and the power division ratio of the Wilkinson power divider. The three-port power divider inherits the performance characteristics of high isolation, low reflection coefficients at all ports, and the minimum number of components. The proposed power divider is designed at 5.8 GHz and fabricated and evaluated through measurements. It demonstrates that electromagnetic simulation results are in good agreement with theoretical prediction and measurement results. The three-port power divider is compact in the planar form, so it can be easily integrated into radio frequency front ends.

  • 47.
    Xu, Xin
    et al.
    Univ Elect Sci and Technol China, Peoples R China.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Broadband and low-loss composite right/left-handed transmission line based on broadside-coupled lines2019In: International Journal of RF and Microwave Computer-Aided Engineering, ISSN 1096-4290, E-ISSN 1099-047X, Vol. 29, no 8, article id e21763Article in journal (Refereed)
    Abstract [en]

    A novel composite right/left-handed (CRLH) transmission line (TL) structure is proposed and investigated. This structure consists of a pair of broadside-coupled lines and a shorted stub. First, its fundamental characteristics and the relation between its electrical parameters and bandwidth are studied utilizing the TL theory. Then, closed-form design equations with flexible parameter selection are given. Finally, several microstrip implementations of the proposed structure are developed to verify our theoretical results. It is shown that the proposed structure can achieve a very wide left-handed (LH) and right-handed (RH) bandwidth with low insertion loss and low return loss.

    The full text will be freely available from 2020-04-03 20:42
  • 48.
    Östh, Joakim
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Owais, Owais
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Baseband complexity comparison of six-, five-, and four-port receivers2012In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 54, no 6, p. 1502-1506Article in journal (Refereed)
    Abstract [en]

    The use of six-port correlators to implement six-port receivers has been intensively studied. The six-port receiver can also be modified to a five-port or a four-port receiver. However, the six-, five-, or four-port receiver solution requires different baseband processing to recover the baseband In-phase (I) and Quadrature-phase (Q) data. A unified mathematical model for the six-, five- and four-port receivers is presented in this article. Possible solutions to recover the baseband data are discussed and compared. The investigation shows that the six-port receiver has advantages over the five- and four-port receivers in terms of complexity when analog baseband processing is used. Simulations are conducted to verify the model and to estimate the error vector magnitude versus frequency; the simulation also shows that the six-port receiver operates over a wider bandwidth than the five- or four-port receiver.

  • 49.
    Östh, Joakim
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    A Comparative Study of Single-Ended vs. Differential Six-Port Modulators for Wireless Communications2015In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 62, no 2, p. 564-570Article in journal (Refereed)
    Abstract [en]

    If present, nonlinear effects in a six-port modulator cause distortion and degradation of the quality of the modulated output waveform. How nonlinear effects occur and their impact on system performance were derived in a mathematical model. The model shows that non-ideal performance of the passive six-port correlator is the main contributor to nonlinear distortion. Simulations and measurements on two manufactured six-port modulators were used to validate the theory and to give deeper insight on system performance. It is shown that by using a differentially signaled six-port modulator instead of a single-ended six-port modulator, better performance is achieved over a wide bandwidth. For an error vector magnitude of less than 10%, the relative bandwidth was measured to 12% for the single-ended but 30% for the differentially signaled modulator

  • 50.
    Östh, Joakim
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Karlsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Serban, Adriana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Carrier Leakage Suppression and EVM Dependence on Phase Shifting Network in Six-Port Modulator2012Conference paper (Refereed)
    Abstract [en]

    In six-port modulators a phase shifting network on specific ports can be used to suppress the carrier leakage that may be present if this network is not present. A model is derived to predict the carrier leakage suppression and error vector magnitude (EVM) as a function of the phase shifting network Sparameters. Both carrier leakage suppression and EVM can be expressed by the same error function. The error function can be used to find the allowed amplitude and phase mismatch in the phase shifting network, or to optimize the performance of a phase shifting network over a given frequency range. A broadband phase shifting network, based on a loaded transmission line, is designed and optimized to operate at a relative bandwidth of 60% for an EVM < 10%. This should be compared to a phase shifting network based on a single transmission line with a corresponding bandwidth of only 12%. The broadband phase shifting network is useful for six-port modulators with carrier leakage suppression, targeting UWB applications.

12 1 - 50 of 58
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