Time domain envelope characterization of power amplifiers for linear and high efficiency design solutions

This paper focuses on the time domain envelope measurements based analysis of power amplifiers in order to improve both linearity and efficiency of microwave transmitters. First of all, a versatile time domain envelope test bench is presented. Then, two applications related to those RF PA measurements are reported. The first application concerns linearity characterization that can be specified in term of Noise Power Ratio (NPR) and Error Vector Magnitude (EVM). Those figures of merit are essential to compute the final bit error rate in a system level simulation tool. A relationship between NPR and EVM is presented and validated by measurements. As a result it can be advantageously used to simplify simulation and measurement procedures for the linearity characterisation of devices and subsystems. The second application is regarding enhancement of the trade-off between linearity and energy efficiency. In order to have a good efficiency, a 10 W class-B GaN Power amplifier is considered. The work presented here, proposes a solution for linearity specifications at large output power back-off thanks to a dynamic gate bias control related to low instantaneous envelope power level. Meanwhile, a dynamic drain bias control handles good efficiency at a constant gain for high instantaneous envelope power level. The measurement-based gate and drain bias trajectory extraction will be fully detailed and take into account GaN dispersive effects such as thermal and trapping effects.

[1]  T. Reveyrand,et al.  A new satellite repeater amplifier characterization system for large bandwidth NPR and modulated signals measurements , 2002, 2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278).

[2]  William R. Panton,et al.  Effects of nonlinear distortion on CDMA communication systems , 1996, IMS 1996.

[3]  Jean-Michel Nebus,et al.  High efficiency class B GaN power amplifier with dynamic gate biasing for improved linearity , 2012 .

[4]  T. Reveyrand,et al.  Time-domain envelope measurements for characterization and behavioral modeling of nonlinear devices with memory , 2006, IEEE Transactions on Microwave Theory and Techniques.

[5]  T. Reveyrand,et al.  A measurement set-up and methodology combining dynamic biasing and baseband predistorsion for high efficiency and linear amplifier design , 2010, 2010 IEEE MTT-S International Microwave Symposium.

[6]  John B. Minkoff.  The Role of AM-to-PM Conversion in Memoryless Nonlinear Systems , 1985, IEEE Trans. Commun..

[7]  Martin Weiß,et al.  Measuring the Dynamic Characteristic of High-Frequency Amplifiers with Real Signals , 2000 .

[8]  Liesbet Van der Perre,et al.  Challenges and enabling technologies for energy aware mobile radio networks , 2010, IEEE Communications Magazine.

[9]  T. Reveyrand,et al.  A Novel Experimental Noise Power Ratio Characterization Method for Multicarrier Microwave Power Amplifiers , 2000, 55th ARFTG Conference Digest.

[10]  Julian J. Bussgang,et al.  Crosscorrelation functions of amplitude-distorted gaussian signals , 1952 .

[11]  T. Reveyrand,et al.  Low frequency parasitic effects in RF transistors and their impact on power amplifier performances , 2012, WAMICON 2012 IEEE Wireless & Microwave Technology Conference.

[12]  R. Westcott.  Investigation of multiple f.m./f.d.m. carriers through a satellite t.w.t. operating near to saturation , 1967 .

[13]  G. Neveux,et al.  Characterization of Galileo signal correlation losses caused by non linear power amplification with memory , 2008, 2008 IEEE MTT-S International Microwave Symposium Digest.

[14]  Patrick Roblin,et al.  Simulation and measurement-based X-parameter models for power amplifiers with envelope tracking , 2013, 2013 IEEE MTT-S International Microwave Symposium Digest (MTT).

[15]  D. Barataud,et al.  Efficient simulation of NPR for the optimum design of satellite transponders SSPAs , 1998, 1998 IEEE MTT-S International Microwave Symposium Digest (Cat. No.98CH36192).

[16]  George Koutitas,et al.  A Review of Energy Efficiency in Telecommunication Networks , 2009 .

[17]  Jacques B. Sombrin,et al.  On the formal identity of EVM and NPR measurement methods: Conditions for identity of error vector magnitude and noise power ratio , 2011, 2011 41st European Microwave Conference.