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  • 1.
    Fritzin, Jonas
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Johansson, Ted
    Infineon Technologies Nordic AB Isafjordsgatan 16, SE-164 81 Stockholm, Sweden.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 72.2Mbit/s LC-Based Power Amplifier in 65nm CMOS for 2.4GHz 802.11n WLAN2008In: Proceedings of the 15th Mixed Design of Integrated Circuits and Systems (MIXDES) Conference, IEEE , 2008, p. 155-158Conference paper (Refereed)
    Abstract [en]

    This paper describes the design and evaluation of a power amplifier (PA) for WLAN 802.11n in 65nm CMOS technology. The PA utilizes 3.3V thick-gate oxide (5.2nm) transistors and a two-stage differential configuration with two integrated inductors for input and interstage matching. For a 72.2Mbit/s, 64-QAM 802.11n OFDM signal at an average and peak output power of 9.4dBm and 17.4dBm, respectively, the measured EVM is 3.8%. The PA meets the spectral mask up to an average output power of 14dBm.

  • 2.
    Fritzin, Jonas
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Johansson, Ted
    Infineon Technologies Nordic AB Isafjordsgatan 16, SE-164 81 Kista, Sweden.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Impedance Matching Techniques in 65nm CMOS Power Amplifiers for 2.4GHz 802.11n WLAN2008In: European Microwave Week 2008, Conference Proceedings, 27-31 October 2008, Amsterdam, The Netherlands, IEEE , 2008, p. 1207-1210Conference paper (Refereed)
    Abstract [en]

    This paper describes the design of two power amplifiers (PA) for WLAN 802.11n fabricated in 65 nm CMOS technology. Both PAs utilize 3.3V thick-gate oxide (5.2 nm) transistors and employ a two-stage differential structure, but the input and interstage matching networks are realized differently. The first PA uses LC matching networks for matching, while the second PA uses on-chip transformers. The impedance matching techniques applied for the matching networks will be described. EVM, output power levels, and spectral masks are obtained for a 72.2 Mbit/s, 64-QAM, 802.11n, OFDM signal.

  • 3.
    Fritzin, Jonas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronic Devices.
    Johansson, Ted
    Infineon Technologies Nordic AB Kista.
    Alvandpour, Atila
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronic Devices.
    Power amplifiers for WLAN in 65nm CMOS2008Conference paper (Other academic)
    Abstract [en]

    This paper describes the design of two power amplifiers (PA) for WLAN 802.11n fabricated in 65nm CMOS technology. Both PAs utilize 3.3V thick-gate oxide (5.2nm) transistors and employ a two-stage differential structure, but the input and interstage matching networks are realized differently. The first PA uses LC matching networks for matching, while the second PA uses on-chip transformers. EVM, output power levels, and spectral masks are obtained for a 72.2Mbit/s, 64-QAM 802.11n OFDM signal.

  • 4.
    Fritzin, Jonas
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Sundström, Timmy
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Reliability study of a low-voltage Class-E power amplifier in 130nm CMOS2010In: Proceedings of IEEE International Symposium on Circuits and Systems (ISCAS), Paris, France, IEEE , 2010, p. 1907-1910Conference paper (Refereed)
    Abstract [en]

    This paper presents reliability measurements of a differential Class-E power amplifier (PA) operating at 850MHz in 130nm CMOS. The RF performance of five samples was tested. At 1.1V, the PAs deliver +20.4–21.5dBm of output power with drain efficiencies and power-added efficiencies of 56–64% and 46–51%, respectively. After a continuous long-term test of 240 hours at elevated supply voltage of 1.4V, the output power dropped about 0.7dB.

  • 5.
    Haque, Muhammad Fahim Ul
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Combined RF and Multilevel PWM Switch Mode Power Amplifier2013In: Norchip Conference, IEEE , 2013, p. 1-4Conference paper (Refereed)
    Abstract [en]

    This paper presents a novel power amplifier (PA) architecture based on the combination of radio frequency pulse width modulation (RFPWM) and multilevel PWM. The architecture provides better dynamic range at high carrier frequency compared to RFPWM. The benefits of this architecture over multilevel PWM are that it only requires a single PA and no combiner. The average efficiency for an 802.11g baseband signal is better than multilevel PWM. Our results also shows that the proposed technique exhibit a constant dynamic range at carrier frequency of 3, 4 and 5 GHz, in contrast to RFPWM which shows a decrease in dynamic range for increase in carrier frequency.

  • 6.
    Haque, Muhammad Fahim Ul
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Combined RF and Multiphase PWM Transmitter2015In: 2015 European Conference on Circuit Theory and Design (ECCTD), IEEE , 2015, p. 264-267Conference paper (Refereed)
    Abstract [en]

    This paper presents two novel transmitter architectures based on the combination of radio-frequency pulse-width modulation and multiphase pulse-width modulation. The proposed transmitter architectures provide good amplitude resolution and large dynamic range at high carrier frequency, which is problematic with existing radio-frequency pulse-width modulation based transmitters. They also have better power efficiency and smaller chip area compared to multiphase pulse-width modulation based transmitters.

  • 7.
    Haque, Muhammad Fahim Ul
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Combined RF and Multiphase PWM Transmitter2015Conference paper (Other academic)
  • 8.
    Haque, Muhammad Fahim Ul
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Modified Band-limited Pulse-Width Modulated Polar Transmitter2015Conference paper (Other academic)
  • 9.
    Haque, Muhammad Fahim Ul
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, The Institute of Technology.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, The Institute of Technology.
    Modified Multilevel PWM Switch Mode Power Amplifier2014Conference paper (Other academic)
  • 10.
    Haque, Muhammad Fahim Ul
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Pasha, Muhammad Touqir
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Aliasing-Compensated Polar PWM Transmitter2017In: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 64, no 8, p. 912-916Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel pulse-width modulation (PWM) transmitter architecture that compensates for aliasing distortion by combining PWM and outphasing. The proposed transmitter can use either switch-mode PAs (SMPAs) or linear PAs at peak power, ensuring maximum efficiency. The transmitter shows better linearity, improved spectral performance and increased dynamic range compared to other polar PWM transmitters as it does not suffer from AM-AM distortion of the PAs and aliasing distortion due to digital PWM. Measurement results show that the proposed architecture achieves an improvement of 8 dB and 4 dB in the dynamic range compared to the digital polar PWM transmitter (PPWMT) and the aliasing-free PWM transmitter (AF-PWMT), respectively. The proposed architecture also shows better efficiency compared to the AF-PWMT.

  • 11.
    Haque, Muhammad Fahim Ul
    et al.
    Department of Electronic Engineering , NED University of Engineering and Technology, Karachi, Pakistan.
    Pasha, Muhammad Touqir
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Power-efficient aliasing-free PWM transmitter2019In: IET Circuits, Devices & Systems, ISSN 1751-858X, E-ISSN 1751-8598, Vol. 13, no 3, p. 273-278Article in journal (Refereed)
    Abstract [en]

    Linearity and efficiency are important parameters in determining the performance of any wireless transmitter. Pulse-width modulation (PWM) based transmitters offer high efficiency but suffer from low linearity due to image and aliasing distortions. Although the problem of linearity can be addressed by using an aliasing-free PWM (AF-PWM), these transmitters have a lower efficiency as they can only use linear power amplifiers (PAs). Moreover, an all-digital implementation of such transmitters is not possible. The aliasing-compensated PWM transmitter (AC-PWMT) has a higher efficiency due to the use of switch-mode PAs (SMPAs) but uses outphasing to eliminate image and aliasing distortions and requires a larger silicon area. In this study, the authors propose a novel transmitter that eliminates both aliasing and image distortions while using a single SMPA. The transmitter can be implemented using all-digital techniques and achieves a higher efficiency as compared to both AF-PWM and AC-PWM based transmitters. Measurement results show an improvement of 11.3, 7.2, and 4.3 dBc in the ACLR as compared to the carrier-based PWM transmitter (C-PWMT), AF-PWMT, and AC-PWMT, respectively. The efficiency of the proposed transmitter is similar to that of C-PWMT, which is an improvement of 5% over AF-PWMT.

  • 12.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    11th Swedish System-on-Chip Conference Sponsored by SSCS-Sweden in May2011Other (Other (popular science, discussion, etc.))
  • 13.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Behovet av mobil beräkningskapacitet ökar snabbare än teknikutvecklingen2011Other (Other (popular science, discussion, etc.))
  • 14.
    Johansson, Ted
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Bengtsson, Olof
    Lotfi, Sara
    Uppsala University, Sweden.
    Vestling, Lars
    Uppsala University, Sweden.
    Norström, Hans
    Uppsala University, Sweden.
    Olsson, Jörgen
    Uppsala University, Sweden.
    Nyström, Christian
    A +32.8 dBm LDMOS power amplifier for WLAN in 65 nm CMOS technology2013Conference paper (Refereed)
    Abstract [en]

    Postlingually acquired hearing impairment (HI) is associated with changes in the representation of sound in semantic long-term memory. An indication of this is the lower performance on visual rhyme judgment tasks in conditions where phonological and orthographic cues mismatch, requiring high reliance on phonological representations. In this study, event-related potentials (ERPs) were used for the first time to investigate the neural correlates of phonological processing in visual rhyme judgments in participants with acquired HI and normal hearing (NH). Rhyme task word pairs rhymed or not and had matching or mismatching orthography. In addition, the inter-stimulus interval (ISI) was manipulated to be either long (800 ms) or short (50 ms). Long ISIs allow for engagement of explicit, top-down processes, while short ISIs limit the involvement of such mechanisms. We hypothesized lower behavioral performance and N400 and N2 deviations in HI in the mismatching rhyme judgment conditions, particularly in short ISI. However, the results showed a different pattern. As expected, behavioral performance in the mismatch conditions was lower in HI than in NH in short ISI, but ERPs did not differ across groups. In contrast, HI performed on a par with NH in long ISI. Further, HI, but not NH, showed an amplified N2-like response in the non-rhyming, orthographically mismatching condition in long ISI. This was also the rhyme condition in which participants in both groups benefited the most from the possibility to engage top-down processes afforded with the longer ISI. Taken together, these results indicate an early ERP signature of HI in this challenging phonological task, likely reflecting use of a compensatory strategy. This strategy is suggested to involve increased reliance on explicit mechanisms such as articulatory recoding and grapheme-to-phoneme conversion.

  • 15.
    Johansson, Ted
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Fritzin, Jonas
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A Review of Watt-Level CMOS RF Power Amplifiers2014In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 62, no 1, p. 111-124Article, review/survey (Refereed)
    Abstract [en]

    This paper reviews the design of watt-level integrated CMOS RF power amplifiers (PAs) and state-of-the-art results in the literature. To reach watt-level output power from a single-chip CMOS PA, two main strategies can be identified: use of high supply voltage and use of matching and power combination. High supply voltage limits are closely related to device design in the fabrication process. However, the maximum operating voltage can be improved by amplifier class selection, circuit solutions, and process modifications or mask changes. High output power can also be reached by the use of on-chip matching and power combination, commonly using on-chip transformers. Reliability often sets the limits for the PA design, and PA degradation mechanisms are reviewed. A compilation of state-of-the-art published results for linear and switched watt-level PAs, as well as a few fully integrated CMOS PAs, is presented and discussed.

  • 16.
    Johansson, Ted
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Landén, L
    Acreo Swedish ICT AB, Norrköping.
    Hossain, M.B.
    Acreo Swedish ICT AB, Norrköping.
    On the Design of an Antenna Switch in 28 nm FD-SOI CMOS2016Conference paper (Other academic)
  • 17.
    Johansson, Ted
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Morales Chacon, Oscar Andres
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Flink, Thomas
    Catena Wireless Electronics AB, Kista, Sweden.
    Digital predistortion with bandwidth limitations for a 28 nm WLAN 802.11ac transmitter2018Conference paper (Other academic)
  • 18.
    Johansson, Ted
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Najari, O
    Catena Wireless Electronics AB, Kista, Sweden.
    Carlsson, M
    Catena Witeless Electronics AB, Kista, Sweden.
    Linear CMOS-PA Design in different 28 nm Technologies2016Conference paper (Other academic)
  • 19.
    Johansson, Ted
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, The Institute of Technology.
    Salter, Michael
    Acreo Swedish ICT AB.
    Vignetti, Matteo
    Acreo Swedish ICT AB.
    Strategies to Multi-Watt PAs in nanometer CMOS2014Conference paper (Other academic)
  • 20.
    Johansson, Ted
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Solati, Noora
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Fritzin, Jonas
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A high-linearity SiGe RF power amplifier for 3G and 4G small basestations2012In: International journal of electronics (Print), ISSN 0020-7217, E-ISSN 1362-3060, Vol. 99, no 8, p. 1145-1153Article in journal (Refereed)
    Abstract [en]

    This article presents the design and evaluation of a linear 3.3V SiGe power amplifier for 3G and 4G femtocells with 18dBm modulated output power at 2140 MHz. Different biasing schemes to achieve high linearity with low standby current were studied. The adjacent channel power ratio linearity performance with wide-band code division multiple access (3G) and long term evolution (4G) downlink signals were compared and differences analysed and explained.

  • 21.
    Morales Chacon, Oscar Andres
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Flink, Thomas
    Catena Wireless Elect AB, Sweden.
    The effect of DPD bandwidth limitation on EVM for a 28 nm WLAN 802.11ac transmitter2017In: 2017 IEEE NORDIC CIRCUITS AND SYSTEMS CONFERENCE (NORCAS): NORCHIP AND INTERNATIONAL SYMPOSIUM OF SYSTEM-ON-CHIP (SOC), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    Digital predistortion (DPD) performance for an IEEE 802.11ac WLAN transmitter in 28 nm CMOS, using 20 and 80 MHz bandwidth with 256QAM modulation, is analyzed under different bandwidth limitations. Due to band-limited conditions in the transmitter chain, the DPD linearization performance may be reduced. For a minimum transmitter error vector magnitude (EVM) requirement of -32 dB (2.5%) for 256QAM modulation, a reduction in the maximum linear output power of 1.6 dB due to bandwidth limitations in the transmitter chain is estimated using simulations and measurement results.

  • 22.
    Pasha, Muhammad Touqir
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Fahim Ul Haque, Muhammad
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering. NED Univ Engn and Technol, Pakistan.
    Ahmad, Jahanzeb
    Intel Corp, England.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    A Modified All-Digital Polar PWM Transmitter2018In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 65, no 2, p. 758-768Article in journal (Refereed)
    Abstract [en]

    This paper presents an all-digital polar pulsewidth modulated (PWM) transmitter for wireless communications. The transmitter combines baseband PWM and outphasing to compensate for the amplitude error in the transmitted signal due to aliasing and image distortion. The PWM is implemented in a field programmable gate array (FPGA) core. The outphasing is implemented as pulse-position modulation using the FPGA transceivers, which drive two switch-mode power amplifiers fabricated in 130-nm standard CMOS. The transmitter has an all-digital implementation that offers the flexibility to adapt it to multi-standard and multi-band signals. As the proposed transmitter compensates for aliasing and image distortion, an improvement in the linearity and spectral performance is observed as compared with a digital-PWM transmitter. For a 20-MHz LTE uplink signal, the measurement results show an improvement of up to 6.9 dBc in the adjacent channel leakage ratio.

  • 23.
    Pasha, Muhammad Touqir
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Fahim Ul Haque, Muhammad
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering. NED Univ Engn and Technol, Pakistan.
    Ahmad, Jahanzeb
    Intel Corp, England.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    An All-Digital PWM Transmitter With Enhanced Phase Resolution2018In: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 65, no 11, p. 1634-1638Article in journal (Refereed)
    Abstract [en]

    An all-digital pulse width modulated (PWM) transmitter using outphasing is proposed. The transmitter uses PWM to encode the amplitude, and outphasing for enhanced phase control. In this way, the phase resolution of the transmitter is doubled. The proposed scheme was implemented using Stratix IV FGPA and class-D PAs fabricated in a 130 nm standard CMOS. From the measurement results, a spectral performance improvement is observed due to the enhanced phase resolution. As compared to an all-digital polar PWM transmitter, the error vector magnitude for proposed transmitter is reduced by 4.1% and the adjacent channel leakage ratio shows an improvement of 5.6 dB for a 1.4 MHz LTE up-link signal for a carrier frequency of 700 MHz at the saturated output power of 25 dBm.

  • 24.
    Touqir Pasha, Muhammad
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Haque, Muhammad Fahim Ul
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Ahmad, Jahanzeb
    University of the West of England, UK.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    An All-Digital Polar PWM Transmitter2018Conference paper (Other academic)
  • 25.
    Touqir Pasha, Muhammad
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Vesterbacka, Mark
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A novel technique to reduce the supply sensitivity of CMOS ring oscillators2014Manuscript (preprint) (Other academic)
    Abstract [en]

    A technique to abbreviate the supply sensitivity of CMOS ring oscillators is presented. By switching the power source from the noisy power supply to a battery during sensitive zero crossings the noise performance of the ring oscillator is improved. The proposed technique can be used in conjunction with other regulation techniques to enhance the performance of ring oscillators in phase locked loops. The proposed switching circuit using a pseudo differential ring oscillator are designed in a 65 nm CMOS process to demonstrate the viability of the proposed scheme in deep submicron process with reduced voltage headroom. At 2 GHz the outputclock exhibits a jitter of less than 14 ps while subjected to a 500 mV noise tone at 500 MHz.

  • 26.
    Ul Haque, Muhammad Fahim
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Large dynamic range PWM transmitter2016Conference paper (Other (popular science, discussion, etc.))
  • 27.
    Ul Haque, Muhammad Fahim
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Power Efficienct Band-limited Pulse Width Modulated Transmitter2015Conference paper (Other (popular science, discussion, etc.))
  • 28.
    Ul Haque, Muhammad Fahim
    et al.
    NED Univ Engn and Technol, Pakistan.
    Touqir Pasha, Muhammad
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Malik, Tahir
    NED Univ Engn and Technol, Pakistan.
    Johansson, Ted
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    A Comparison of Polar and Quadrature RF-PWM2018In: 2018 IEEE NORDIC CIRCUITS AND SYSTEMS CONFERENCE (NORCAS): NORCHIP AND INTERNATIONAL SYMPOSIUM OF SYSTEM-ON-CHIP (SOC), Institute of Electrical and Electronics Engineers (IEEE), 2018Conference paper (Refereed)
    Abstract [en]

    All-digital implementations of PWM-based wireless transmitters are gaining popularity. Unlike baseband PWM, RF-PWM has relaxed filtering requirements and is preferred due to a smaller chip size. This paper is aimed to highlight the differences between polar and quadrature implementations of RF-PWM-based transmitters. Using mathematical models and simulations, performance of the two implementations is compared. The mathematical analysis indicates that the quadrature implementation is expected to have higher quantization noise compared to the polar because of the shorter duty cycles at maximum amplitude. The simulations, using a 10 MHz LTE uplink signal at 2 GHz carrier frequency, confirm this and also show the effect of RF pulse swallowing on the error vector magnitude (EVM).

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