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Serban (Craciunescu), AdrianaORCID iD iconorcid.org/0000-0003-2117-1178
Alternative names
Publications (10 of 43) Show all publications
Jakobsson, A., Serban, A. & Gong, S. (2019). A Low Noise RC-based Phase Interpolator in 16-nm CMOS. IEEE Transactions on Circuits and Systems - II - Express Briefs, 66(1)
Open this publication in new window or tab >>A Low Noise RC-based Phase Interpolator in 16-nm CMOS
2019 (English)In: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 66, no 1Article in journal (Refereed) Published
Abstract [en]

This paper describes a passive analog phase interpolator, utilizing a switched RC-network. The proposed circuit eliminates the current sources in a phase interpolator based on constant-slope charging. By eliminating the current source, the noise is significantly reduced due to the reduction in thermal and flicker noise. The phase interpolator has a resolution of 6 bits and is implemented in a 16-nm CMOS process. The maximum differential non-linearity is measured to be 0.1 LSBs at a 192 ps input time delta. The circuit draws 0.2 mW from a 0.8 V supply, and occupies 0.004 mm2.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-147285 (URN)10.1109/TCSII.2018.2823902 (DOI)000454341300001 ()
Available from: 2018-04-13 Created: 2018-04-13 Last updated: 2019-01-11
Wu, D., Serban, A., Karlsson, M. & Gong, S. (2018). Highly Unequal Three-Port Power Divider: Theory and Implementation. International Journal of Antennas and Propagation, Article ID 9141964.
Open this publication in new window or tab >>Highly Unequal Three-Port Power Divider: Theory and Implementation
2018 (English)In: International Journal of Antennas and Propagation, ISSN 1687-5869, E-ISSN 1687-5877, article id 9141964Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2018
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-149999 (URN)10.1155/2018/9141964 (DOI)000440492900001 ()
Available from: 2018-08-06 Created: 2018-08-06 Last updated: 2019-06-17
Serban (Craciunescu), A., Morales, O., Petersson, T., Kalvér, H. & Ye, Q.-Z. (2018). Multi-Port Front-End and DSP Co-Design for Vital Signs Detector. In: : . Paper presented at Swedish Microwave Days, GigaHertz Symposium, Lund, Sweden, May 24-25, 2018. Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Multi-Port Front-End and DSP Co-Design for Vital Signs Detector
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2018 (English)Conference paper, Oral presentation only (Refereed)
Abstract [en]

Controlled wave interferometry within the passive multi-port (six-port) correlator with capability to accurately process phase information is shown to be a useful technique for microwave radar and wireless sensor applications. In this paper, the co-design and implementation of a complete hardware-software Doppler radar modular system for vital signs detection using the multi-port technology is presented. In contrast to multi-port radio applications, the challenge is to demonstrate the possibility to detect weak, Hz-range frequency signals.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2018
Keywords
multi-port radar, vital signs detection, co-design, digital signal processing
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-150613 (URN)
Conference
Swedish Microwave Days, GigaHertz Symposium, Lund, Sweden, May 24-25, 2018
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2019-06-17Bibliographically approved
Gong, S., Östh, J., Serban, A. & Karlsson, M. (2016). Six-port Modulators for High Speed Data. In: GigaHertz Symposium 2016: . Paper presented at Swedish Microwave Days (pp. 65). Linköping
Open this publication in new window or tab >>Six-port Modulators for High Speed Data
2016 (English)In: GigaHertz Symposium 2016, Linköping, 2016, p. 65-Conference paper, Oral presentation with published abstract (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.

Place, publisher, year, edition, pages
Linköping: , 2016
Keywords
six-port radio, six-port modulator, high speed data transmission
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-129187 (URN)
Conference
Swedish Microwave Days
Available from: 2016-06-13 Created: 2016-06-13 Last updated: 2019-06-17
Östh, J., Karlsson, M., Serban, A. & Gong, S. (2015). A Comparative Study of Single-Ended vs. Differential Six-Port Modulators for Wireless Communications. IEEE Transactions on Circuits and Systems Part 1: Regular Papers, 62(2), 564-570
Open this publication in new window or tab >>A Comparative Study of Single-Ended vs. Differential Six-Port Modulators for Wireless Communications
2015 (English)In: 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) Published
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

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2015
Keywords
Differential; modulation order; non-linearity; single-ended; six-port; six-port correlator; six-port modulator
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-115331 (URN)10.1109/TCSI.2014.2362310 (DOI)000349399800025 ()
Available from: 2015-03-13 Created: 2015-03-13 Last updated: 2019-08-12Bibliographically approved
Jakobsson, A., Serban, A. & Gong, S. (2015). Implementation of Quantized-State System Models for a PLL Loop Filter Using Verilog-AMS. IEEE Transactions on Circuits and Systems Part 1: Regular Papers, 62(3), 680-688
Open this publication in new window or tab >>Implementation of Quantized-State System Models for a PLL Loop Filter Using Verilog-AMS
2015 (English)In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 62, no 3, p. 680-688Article in journal (Refereed) Published
Abstract [en]

A method to implement quantized-state system (QSS) models in industry standard RF-IC design tools is proposed. The method is used to model a GHz-range 0.18 um CMOS phase-locked loop (PLL), and enables a truly event-driven simulation of the entire mixed-signal PLL circuit. First- and second-order (QSS and QSS2, respectively) models of the PLL loop-filter implemented in Verilog-AMS are first described in detail. These models do not rely on analog nets, and use only the event-based solver. Then, simulation results are compared to reference SPICE simulation results to prove the validity of the QSS method. The entire PLL circuit is finally simulated using the QSS model of the loop-filter, charge-pump and VCO, in conjunction with standard high-level models of the PLL digital circuits. To verify the proposed QSS method, measured phase noise is compared with simulated phase noise. It is shown that simulated phase noise accurately predicts the measured phase noise with improved accuracy, and an increase in simulation efficiency by more than 50 times. Measured and simulated results generally demonstrate the feasibility of the QSS modeling for mixed-signal circuit simulation and design.

Place, publisher, year, edition, pages
IEEE Computer Society, 2015
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-115601 (URN)10.1109/TCSI.2014.2377411 (DOI)000350799100008 ()
Available from: 2015-03-17 Created: 2015-03-17 Last updated: 2017-12-04
Tatu, S. O., Serban, A., Koelpin, A. & Helaoui, M. (2014). Multiport technology: New perspectives and applications. Journal of Electrical and Computer Engineering, 2014(194649)
Open this publication in new window or tab >>Multiport technology: New perspectives and applications
2014 (English)In: Journal of Electrical and Computer Engineering, ISSN 2090-0147, E-ISSN 2090-0155, Vol. 2014, no 194649Article in journal, Editorial material (Other academic) Published
Abstract [en]

Since 1994, the multiport techniques were further developed for microwave and millimeter-wave radios. Until today, several multiport architectures for specific applications, such as communication transceivers, radar, sensing, direction of arrival estimation, or phase noise measurements, have been developed and implemented.

This special issue highlights, through several examples and multiple references, some of the modern applications of the multiport technology and significant advances in fabrication procedures, in the recent years.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2014
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-112563 (URN)10.1155/2014/194649 (DOI)
Available from: 2014-12-02 Created: 2014-12-02 Last updated: 2017-12-05
Tatu, S. O., Serban, A., Helaoui, M. & Koelpin, A. (2014). Multiport Technology: The New Rise of an Old Concept. IEEE Microwave Magazine, 15(7), 34-44
Open this publication in new window or tab >>Multiport Technology: The New Rise of an Old Concept
2014 (English)In: IEEE Microwave Magazine, ISSN 1527-3342, E-ISSN 1557-9581, Vol. 15, no 7, p. 34-44Article in journal (Refereed) Published
Abstract [en]

This article provides an overview of the basics, possible applications, and specific calibration procedures for the six-port circuit, which is the most common multiport implementation of this promising architecture.

Place, publisher, year, edition, pages
IEEE, 2014
Keywords
Multiport, six-port, direct modulator, demodulator, wideband receiver, localization
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-112560 (URN)10.1109/MMM.2014.2356149 (DOI)000346043100009 ()
Available from: 2014-12-02 Created: 2014-12-02 Last updated: 2017-12-05
Jakobsson, A., Grewing, C., Gong, S. & Serban, A. (2013). Dual Loop Gain Calibration of Frequency Synthesizer. In: : . Paper presented at Swedish System on Chip Conference (SSoCC).
Open this publication in new window or tab >>Dual Loop Gain Calibration of Frequency Synthesizer
2013 (English)Conference paper, Oral presentation with published abstract (Refereed)
Keywords
PLLs, calibration methods, frequency synthesizers
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-115605 (URN)
Conference
Swedish System on Chip Conference (SSoCC)
Available from: 2015-03-17 Created: 2015-03-17 Last updated: 2015-03-30
Jakobsson, A., Grewing, C., Serban, A. & Gong, S. (2013). Frequency Synthesizer With Dual Loop Frequency and Gain Calibration. IEEE Transactions on Circuits and Systems Part 1: Regular Papers, 60(11), 2911-2919
Open this publication in new window or tab >>Frequency Synthesizer With Dual Loop Frequency and Gain Calibration
2013 (English)In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 60, no 11, p. 2911-2919Article in journal (Refereed) Published
Abstract [en]

A 3600-MHz phase-locked loop based frequency synthesizer for UMTS applications has been developed in 0.18 $mu$ m CMOS. It incorporates a VCO frequency and loop-gain calibration technique that allows an integrated VCO frequency tuning range of 28% and a low VCO gain ($K_{rm VCO}$ of 30 MHz/V. The loop-gain calibration can compensate for not only variations in VCO gain and divider modulus, but also charge-pump current and loop filter capacitance to an accuracy of 5%. The PLL settles in 150 $mu$s including frequency and gain calibrations. No switches are used in the loop filter. The output phase noise at 1-MHz offset is ${-}123$ dBc/Hz and the integrated phase error (1 kHz–2 MHz) is 1.26 $^{circ}$.

Place, publisher, year, edition, pages
IEEE, 2013
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-100996 (URN)10.1109/TCSI.2013.2256191 (DOI)000326631000010 ()
Available from: 2013-11-16 Created: 2013-11-16 Last updated: 2018-07-19
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2117-1178

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