# Publications

**Patents**

[P1] S. Hatami, M. Helaoui, R. Negra, and F. M. Ghannouchi, "All-Digital Multi-standard transmitter Architecture using Sigma Delta Modulators", PCT provisional patent application, filed Nov. 2, 2007, PCT patent WO/2009/055897, May 2009, US patent application 60/996140, filed March 20, 2009

**Journal papers**

**2010**

[J18] J. Guan, B.T. Thiel, N. Zimmermann, R. Negra, ”Modelling and simulation of mixed-signal RF transmitters at architectural level in SystemC/AMS,“ Int’l Journal on Microwave and Optical Technology, Vol. 5, No. 6, pp.409–418, Nov. 2010

[J17] F. M. Ghannouchi, S. Hatami, P. Aflaki, M. Helaoui, and R. Negra, ”Accurate Power Efficiency Estimation of GHz Wireless Delta-Sigma Transmitters for Different Classes of Switching Mode Power Amplifiers,“ IEEE Tran. Microwave Theory and Techn., Vol. 58, pp.2812–2819, Nov. 2010

[J16] A. Jarndal, P. Aflaki, R. Negra, A. Kouki, and F. M. Ghannouchi, ”Large-Signal Modeling Methodology for GaN HEMTs for RF Switching-Mode Power Amplifiers Design,“ Int’l Journal of

RF and Microwave Computer-Aided Engineering, Vol. 21, No. 1, pp.45–51, Dec. 2010[J15] Sung-Chang Jung, R. Negra, and F. M. Ghannouchi, "Analysis of Miniaturized 3 dB Branch-Line Hybrid Couplers using Distributed MIM Capacitors," Microwave and Optical Technology Letters, Vol. 52, No. 7, pp.1553-1556, July 2010

[J14] A. Jarndal, P. Aflaki, L. Degachi, A. Birafane, A. Kouki, R. Negra, and F. M. Ghannouchi, "Large-signal model for AlGaN/GaN HEMTs suitable for RF switching-mode power amplifiers design," Solid-State Electronics, Vol. 54, No. 7, pp.696-700, Jul. 2010

**2009**

[J13] P. Aflaki, R. Negra and F. M. Ghannouchi, "Dedicated large-signal GaN HEMT model for switching-mode circuit analysis and design,"IEEE Microwave and Wireless Components Letters, Vol. 19, No. 11, pp.740–742, Nov. 2009

[J12] S.-C. Jung, K.-H. Lim, H.-C. Park, R. Negra, M.-Su Kim, F. M. Ghannouchi, and Y. Yang, "A load network for Doherty amplifiers using an optimized impedance transformer,"Microwave and Optical Technology Letters, Vol. 51, pp.2502–2504, Oct. 2009

[J11] P. Aflaki, R. Negra and F. M. Ghannouchi, "Enhanced Architecture for Microwave Current Mode Class-D Amplifiers Applied to the Design of an S-Band GaN-Based PA,"IET Microwave Antenna & Propagation, Vol.3, No. 6, pp.997–1006, Sep. 2009

**2008**

[J10] S.-C. Jung, R. Negra, and F. M. Ghannouchi, "A Design Methodology for Miniaturized 3-dB Branch-Line Hybrid Couplers Using Distributed Capacitors Printed in the Inner Area,"IEEE Tran. Microwave Theory and Techn., Vol. 56, No. 12, pp.2950–2953, Dec. 2008

[J9] R. Negra, F. M. Ghannouchi, and W. Bächtold, "Analysis and evaluation of harmonic suppression of lumped-element networks suitable for high-frequency class-E operation condition approximation,"IET Microwave Antenna & Propagation, Vol.2, No. 8, pp.794–800, Dec. 2008

[J8] M. Helaoui, S. Hatami, R. Negra, and F. M. Ghannouchi, "A Novel Architecture of Delta-Sigma Modulator Enabling All-Digital Multiband Multistandard RF Transmitters Design,"IEEE Tran. Circuits and Systems II, Vol. 55, No. 11, pp.1129–1133, Nov. 2008

[J7] P. Aflaki, R. Negra, and F. M. Ghannouchi, "1 GHz current-mode class-D power amplifier in hybrid technology using GaN HEMTs,"Romanian Journal of Information Science and Technology (ROMJIST), Vol. 11, pp.319–328, Apr. 2008

[J6] R. Negra, A. Sadeve, S. Bensmida, and F. M. Ghannouchi, "Concurrent dual-band class-F load coupling network for applications at 1.7 GHz and 2.14 GHz,"IEEE Tran. Circuits and Systems II, Vol. 55, No. 3, pp.259–263, Mar. 2008

[J5] S. Bensmida, P. Poiré, R. Negra, and F. M. Ghannouchi, "A New Setup for Time-Domain Voltage/Current Waveforms Measurements Based on Six-Port Reflectometry Suitable for Large Signal Transistor Characterization and Power Amplifier Design and Optimization,"IEEE Tran. Microwave Theory and Techn., Vol. 56, No. 1, pp.224–231, Jan. 2008

**2007**

[J4] R. Negra, F. M. Ghannouchi, and W. Bächtold, "Study and design optimisation of multiharmonic transmission-line load networks for class-E and class-F K-band MMIC power amplifiers,"IEEE Tran. Microwave Theory and Techn., Vol. 55, No. 6, pp.1390–1397, June 2007

**2006**

[J3] R. Negra and W. Bächtold, "Ka-band coplanar class-F MMIC power amplifier in a GaAs pHEMT technology,"Int'l. Journal on Microwave and Optical Technology, Vol. 1, pp.771–774, Aug. 2006

[J2] R. Negra and W. Bächtold, "Lumped-element load-network design for class-E power amplifiers,"IEEE Tran. Microwave Theory and Techn., Vol. 54, No.6, pp.2684–2690, June 2006

**2004**

[J1] T. Brauner, R. Negra, R. Vogt, W. Bächtold, "PA Calibration in TDMA Antenna Arrays,"IEEE Microwave and Wireless Components Letters, Vol. 14, Nr.12, pp.548–550, 2004

**Conference proceedings**

**2011**

[C48 ] J. Guan, A.F. Aref, R. Negra, ”System-level performance study of a multistandard outphasing transmitter using optimised multilevels,“ IEEE Int’l Microwave Symposium (IMS 2011), June 2011 (in press)

[C47 ] B. T. Thiel, Y.A. Özmert, J. Guan, R. Negra, ”Lowpass Delta-Sigma Modulator with Digital Upconversion for Switching Mode Power Amplifiers,“ IEEE Int’l Microwave Symposium (IMS 2011) in June 2011 (in press)

[C46 ] D. Kalim, R. Negra, ”Concurrent planar multiharmonic dual-band load coupling network for switching-mode power amplifiers,“ IEEE Int’l Microwave Symposium (IMS 2011) in June 2010 (in press)

[C45 ] D. Kalim, A. Khan, R. Negra, ”Common-Drain Class-B Power Amplifier in 90 nm CMOS,“ Integrated Nonlinear Microwave and Millimetre-wave Circuits (INMMiC 2011), Apr. 2011 (in press)

[C44 ] B. T. Thiel, N. Zimmermann, R. Negra, ”Digitally controlled 3 GHz 360 degree Phase Modulator in a 1.2 V 65 nm CMOS process“, Proc. German Microwave Conf. (GeMiC 2011), pp., Mar. 2011 (in press)

**2010**

[C43 ] B. T. Thiel, S. Dietrich, R. Negra, ”Digital Asynchronous Signal Interpolation and Clock Domain Crossing“, Asia Pacific Microwave Conference (APMC 2010), pp.1420–1423, Dec. 2010

[C42 ] M.D. Wei, S.F. Chang, R. Negra, ”Low-Power Consumption CMOS VCO“, RadioTecC 2010, Nov. 2010

[C41 ] M.D. Wei, S.F. Chang, R. Negra, ”A DC-Invariant Gain Control Technique for CMOS Differential Variable-Gain Low-Noise Amplifiers“, 28th IEEE NORCHIP Conference 2010, pp.1–4, Nov. 2010

[C40 ] J. Guan, R. Negra, "Modelling and simulation of an RF-DAC based transmitter at architectural level in SystemC/AMS", 6th Conf. Ph.D. Research Microelectronics & Electronics (PRIME 2010), July 2010

[C39 ] B. Mohr, N. Zimmermann, B. T. Thiel, R. Negra, and S. Heinen "Digital Shaping of Static and Dynamic Mismatch Errors in Digital to Analog Converters", 6th Conf. Ph.D. Research Microelectronics & Electronics (PRIME 2010), July 2010

[C38 ] D. Kalim, D. Erguvan, R. Negra, "A 1.7 GHz-3.4 GHz fully integrated broadband class-E power amplifier in 90nm CMOS", 6th Conf. Ph.D. Research Microelectronics & Electronics (PRIME 2010), July 2010

[C37 ] B. T. Thiel, S. Dietrich, R. Negra, "Digital Polyphase Baseband for Direct Digital Generation of High Sample Rate Radio Frequency Signals", 6th Conf. Ph.D. Research Microelectronics & Electronics (PRIME 2010), July 2010

[C36 ] B. Mohr, N. Zimmermann, B. T. Thiel, R. Negra, S. Heinen, "Optimized Mismatch Shaping for an RF-DAC Based OFDM Transmitter", 8th IEEE Int'l NEWCAS Conf. (NEWCAS 2010), pp.201–204, June 2010

[C35 ] N. Zimmermann, Y. Wang, B. T. Thiel, B. Mohr, J. Müller, R. Negra

and S. Heinen "Design of an RF-DAC Based Transmitter in 65nm CMOS," CDNLive! EMEA 2010, Mar. 2010[C34 ] P. Aflaki, R. Negra, and F. M. Ghannouchi, "Dual-band hybrid balun structure using transmissionlines and lumped component resonators", IEEE Int’l Microwave Symposium (IMS 2010), pp.1572–1575, May 2010

[C33 ] D. Kalim, D. Erguvan, R. Negra, "Study on CMOS class-E power amplifiers for LTE applications,"Proc. German Microwave Conf. (GeMiC 2010), pp.186–189, Mar. 2010

**2009**

[C32 ] R. Negra, D. Kalim, D. Erguvan, F. M. Ghannouchi "On the design of broadband/multiband highly efficient power amplifiers,"12th Int'l Symposium on Microwave and Optical Technology (ISMOT 2009), pp.377–378, Dec. 2009

[C31 ] J. Guan, R. Negra, "Modelling and simulation of mixed-signal RF transmitters at architectural level in SystemC/AMS,"12th Int'l Symposium on Microwave and Optical Technology (ISMOT 2009), pp.381–382, Dec. 2009

[C30 ] B. T. Thiel, S. Dietrich, R. Negra, "High Frequency Serializer for Direct-Digital-Upconversion,"12th Int'l Symposium on Microwave and Optical Technology (ISMOT 2009), pp.383–384, Dec. 2009

[C29 ] D. Kalim, Kui Chen, Huifang Yan, R. Negra, "Comparison of class-E and class-F-1 switching-mode power amplifiers on a GaN HEMT technology,"12th Int'l Symposium on Microwave and Optical Technology (ISMOT 2009), pp.385–386, Dec. 2009

[C28 ] N. Zimmermann, R. Negra, S. Heinen, "Design of an RF-DAC in 65 nm CMOS for Multistandard, Multimode Transmitters,"IEEE Int'l Symp. Radio-Frequency Integration Techn. (RFIT 2009), pp., Dec. 2009

[C27 ] A. Jarndal, P. Aflaki, L. Degachi, A. Birafane, A. Kouki, R. Negra, F. M. Ghannouchi, "On the Large-Signal Modeling of AlGaN/GaN HEMTs for RF Switching-Mode Power Amplifiers Design,"Asia Pacific Microwave Conference (APMC 2009), pp.2356–2359, Dec. 2009

[C26 ] S.-C. Jung, R. Negra, F. M. Ghannouchi, "A miniaturized double-stage 3dB broadband branch-line hybrid coupler using distributed capacitors,"Asia Pacific Microwave Conference (APMC 2009), pp.1323–1326, Dec. 2009

[C25 ] B. T. Thiel, S. Dietrich, N. Zimmermann, R. Negra, "System Architecture of an All-Digital GHz Transmitter using Pulse-Width/Position-Modulation for Switching-Mode PAs,"Asia Pacific Microwave Conference (APMC 2009), pp.2340–2343, Dec. 2009

[C24 ] P. Aflaki, R. Negra, and F. M. Ghannouchi, "Intrinsic capacitances effects on the accuracy of the large-signal switch-based GaN device model,"Asia Pacific Microwave Conference (APMC 2009), pp.281– 284, Dec. 2009

[C23 ] D. Kalim, D. Erguvan, R. Negra, "Broadband CMOS class-E power amplifiers for LTE applications,"Int'l. Conference on Signals, Circuits and Systems (SCS 2009), pp. , Nov. 2009

[C22 ] N. Zimmermann, B. T. Thiel, R. Negra, S. Heinen, "System Architecture of an RF-DAC Based Multi-Standard Transmitter,"IEEE Int'l Midwest Symposium on Circuits and Systems (MWSCAS 2009), pp.248–251, Aug. 2009

[C21 ] D. Kalim, H. Erkens, R. Wunderlich, R. Negra, and S. Heinen, "Switching-mode Differential Class-E Amplifier for Phased Array Radar,"Proc. German Microwave Conference (GeMiC 2009), pp. 1–4, Mar. 2009

[C20 ] R. Negra, F. M. Ghannouchi, "Monolithic lumped-element unequal branch-line coupler for the use in asymmetrical Doherty amplifiers,"IEEE Topical Symp. Power Amplifiers for Wireless Communications (PAS 2009), Jan. 2009

[C19 ] P. Aflaki, R. Negra and F. M. Ghannouchi, "Proper balun structures for microwave current mode class-D switching-mode power amplifiers,"IEEE Topical Symp. Power Amplifiers for Wireless Communications (PAS 2009), Jan. 2009

**2008**

[C18 ] P. Aflaki, H. G. Bae, R. Negra, and F. M. Ghannouchi, "Novel compact transmission-line output network topology for class-E power amplifiers,"Proc. 38th European Microwave Conference (EuMC 2008), pp.238–241, Oct. 2008

[C17 ] P. Aflaki, R. Negra, A. Mohammadi and F. M. Ghannouchi, "A New Approach to Design a Frequency Synthesizer Using Direct Digital Synthesis Technique,"IEEE Canadian Conference on Electrical and Computer Engineering (CCECE 2008), pp.1733–1736, May 2008

[C16 ] Sung-Chan Jung, Kyoung-Hoon Lim, Hyun-Chul Park, Min-Su Kim, Ju-Ho Van, Jong-Hyuk Jeong, Sung-Wook Kwon, Yao-Xi, Hanjin Cho, R. Negra, F. M. Ghannouchi, and Young-Goo Yang, "Doherty Power Amplifier with an Optimized Load Network for Improved Linearity and Efficiency,"Int’l. Symp. on Foundations of Emerging Information Techn. (FEIT2008), pp.24–28, Jan. 2008

[C15 ] P. Aflaki, R. Negra, and F. M. Ghannouchi, "Design and Implementation of an Inverse Class-F Power Amplifier with 79 % Efficiency by using a Switch-based Active Device Model,"IEEE Radio Wireless Symposium (RWS 2008), pp. 423–426, Jan. 2008

**2007**

[C14 ] R. Negra, F. M. Ghannouchi, and W. Bächtold, "Harmonic suppression performance of a 5 GHz MMIC class-E PA using a lowpass lumped-element impedance termination approximation,"Asia Pacific Microwave Conference (APMC 2007), pp.1829-1832, Dec. 2007

[C13 ] S. Hatami, R. Negra, and F. M. Ghannouchi, "Multiband Multistandard Delta-Sigma-based RF Transmitters,"Software Defined Radio Technical Conference (SDR’07 Tech Conf), Nov. 2007

[C12 ] P. Aflaki, R. Negra, and F. M. Ghannouchi, "Compact load-coupling network for microwave current mode class-D power amplifiers,"Int'l Conference of Semiconductors (CAS 2007), pp.233-236, Oct. 2007

[C11 ] H. G. Bae, R. Negra, S. Boumaiza, and F. M. Ghannouchi, "High-efficiency GaN class-E power amplifier with compact harmonic-suppression network,"Proc. 37th European Microwave Conference (EuMC 2007), pp.1093–1096, Oct. 2007

[C10 ] R. Negra, T. D. Chu, M. Helaoui, S. Boumaiza, G. M. Hegazi, and F. M. Ghannouchi, "Switch-based GaN HEMT model suitable for highly-efficient RF power amplifier design,"IEEE Int'l Microwave Symposium (IMS 2007), pp.795-798, June 2007

[C9 ] M. Helaoui, N. Demirel, R. Negra, S. Boumaiza, E. Kerhervé, A. Ghazel, and F. M. Ghannouchi, "Digitally Optimised Delta-Sigma Modulator for WiMAX Transmitter Design,"Proc. IEEE Radio Wireless Symposium (RWS 2007), pp.419-422, Jan. 2007

**2006**

[C8 ] R. Negra, F. M. Ghannouchi, and W. Bächtold, "Compact device-level linearisation technique using a reduced complexity derivative superposition approach,"Proc. Asia Pacific Microwave Conference (APMC 2006), pp.1739-1742, Dec. 2006

[C7 ] N. Demirel, R. Negra, E. Kerhervé, and F. M. Ghannouchi, "A Study of High-Frequency Bandpass Delta-Sigma Transmitter Architectures,"Proc. 13th IEEE Int'l Conference on Electronic System and Circuits (ICECS 2006), pp. 1117-1120, Dec. 2006

[C6 ] R. Negra, F. M. Ghannouchi, and W. Bächtold, "On the design of MMIC multi-harmonic load terminations for class-F amplifiers,"Proc. 36th European Microwave Conference (EuMC 2006), pp.180-183, Sep. 2006

**2005**

[C5 ] R. Negra and W. Bächtold, "BiCMOS MMIC class-E power amplifiers for 5 to 6 GHz wireless communication systems,"Proc. 35th European Microwave Conference (EuMC 2005), pp.445-448, Oct. 2005

[C4 ] R. Negra and W. Bächtold, "Ka-band coplanar class-F MMIC power amplifier in a GaAs pHEMT technology,"10th Int'l Symposium on Microwave and Optical Technology (ISMOT 2005), pp.771- 774, Aug. 2005

**2004**

[C3 ] R. Negra and W. Bächtold, "24 GHz low-voltage class-E power amplifier in GaAs pHEMT technology,"Asia Pacific Microwave Conference (APMC’04), pp.826, Dec. 2004

[C2 ] R. Negra and W. Bächtold, "Switched-mode high-efficiency Ka-band MMIC power amplifier in GaAs pHEMT technology,"12th Int'l Symposium on Electron Devices for Microwave and Optoelectronic Applications (EDMO 2004), pp.15-18, Nov. 2004

**2003**

[C1 ] R. Negra, R. Vogt, W. Bächtold, "High power density monolithic linear X-band power amplifier using a low-cost MESFET technology,"

Int'l Microwave and Optoelectronics Conference (IMOC 2003), pp.877-880, Sep. 2003

**Workshop and short course contributions**

[W6] R. Negra, N. Zimmermann, T.B. Thiel, B. Mohr, S. Heinen ”Flexible Digital-Centric RF-DAC Based Transmitter,“ IEEE Int’l Solid-State Circuits Conf. Forum (ISSCC 2011) to be delivered in Feb. 2011

[W5] R. Negra, ”Software Defined and Cognitive Radios from the RF Point of View“, Workshop organiser, EEEfCOM 2010, June 2010[W4] R. Negra, F. M. Ghannouchi, "Recent advances in switching-mode amplifier design," Workshop,

IEEE Int'l Microwave Symposium (IMS 2008), Juni 2008[W3] R. Negra, F. M. Ghannouchi, "Switching-mode power amplifiers and their application in advanced wireless communication transmitters," Short course,

IEEE Radiowireless Symposium (RWS 2008), Jan. 2008[W2] R. Negra, F. M. Ghannouchi, "Device modelling for switching-mode applications," Workshop on

Transmitter Design for High Power Efficiency: the path from device to advanced system architectures,IEEE Radio Wireless Symposium (RWS 2008), Jan. 2008[W1] R. Negra, F. M. Ghannouchi, and W. Bächtold, "Practical aspects in designing MMIC switching

mode amplifiers", Workshop on Switching-mode Amplifiers with Applications to Wireless Transmitters Design,IEEE Int'l Microwave Symposium (IMS 2006), Juni 2006