Design of a Wideband Doherty Power Amplifier with High Efficiency for 5G Application

This paper discusses the design of a wideband class AB-C Doherty power amplifier suitable for 5G applications. Theoretical analysis of the output matching network is presented, focusing on the impact of the non-ideally infinite output impedance of the auxiliary amplifier in back off, due to the device’s parasitic elements. By properly accounting for this effect, the designed output matching network was able to follow the desired impedance trajectories across the 2.8 GHz to 3.6 GHz range (fractional bandwidth = 25%), with a good trade-off between efficiency and bandwidth. The Doherty power amplifier was designed with two 10 W packaged GaN HEMTs. The measurement results showed that it provided 43 dBm to 44.2 dBm saturated output power and 8 dB to 13.5 dB linear power gain over the entire band. The achieved drain efficiency was between 62% and 76.5% at saturation and between 44% and 56% at 6 dB of output power back-off.

[1]  Christian Fager,et al.  Doherty's Legacy: A History of the Doherty Power Amplifier from 1936 to the Present Day , 2016, IEEE Microwave Magazine.

[2]  Marius Otesteanu,et al.  WiMAX versus LTE - An overview of technical aspects for next generation networks technologies , 2010, 2010 9th International Symposium on Electronics and Telecommunications.

[3]  Tao Jiang,et al.  A Design Strategy for AM/PM Compensation in GaN Doherty Power Amplifiers , 2017, IEEE Access.

[4]  Franco Giannini,et al.  A comprehensive comparison between GaN MMIC Doherty and combined class-AB power amplifiers for microwave radio links , 2016, International Journal of Microwave and Wireless Technologies.

[5]  Robert Bogdan Staszewski,et al.  Broadband Fully Integrated GaN Power Amplifier With Minimum-Inductance BPF Matching and Two-Transistor AM-PM Compensation , 2020, IEEE Transactions on Circuits and Systems I: Regular Papers.

[6]  G. Ghione,et al.  3–3.6-GHz Wideband GaN Doherty Power Amplifier Exploiting Output Compensation Stages , 2012, IEEE Transactions on Microwave Theory and Techniques.

[8]  Vincent Fusco,et al.  Toward a More Generalized Doherty Power Amplifier Design for Broadband Operation , 2017, IEEE Transactions on Microwave Theory and Techniques.

[9]  Rolf H. Jansen,et al.  Broadband Doherty Power Amplifier via Real Frequency Technique , 2012, IEEE Transactions on Microwave Theory and Techniques.

[10]  Zoya Popovic,et al.  Multilevel Supply-Modulated Chireix Outphasing With Continuous Input Modulation , 2017, IEEE Transactions on Microwave Theory and Techniques.

[11]  Wooseok Lee,et al.  Octave Bandwidth Doherty Power Amplifier Using Multiple Resonance Circuit for the Peaking Amplifier , 2019, IEEE Transactions on Circuits and Systems I: Regular Papers.

[12]  Yue Li,et al.  Two-Port Network Theory-Based Design Method for Broadband Class J Doherty Amplifiers , 2019, IEEE Access.

[13]  Gee-Kung Chang,et al.  Integrated fiber-wireless access architecture for mobile backhaul and fronthaul in 5G wireless data networks , 2014, 2014 IEEE Avionics, Fiber-Optics and Photonics Technology Conference (AVFOP).

[14]  Roberto Quaglia,et al.  Design of an S-Band Chireix Outphasing Power Amplifier Based on a Systematic Bandwidth Limitation Analysis , 2018, 2018 13th European Microwave Integrated Circuits Conference (EuMIC).

[16]  Marco Pirola,et al.  Dual-input driving strategies for performance enhancement of a doherty power amplifier , 2018, 2018 IEEE MTT-S International Wireless Symposium (IWS).

[17]  Marco Pirola,et al.  High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach , 2017 .

[18]  M. Ohtomo.  Stability analysis and numerical simulation of multidevice amplifiers , 1993 .

[19]  Jun Peng,et al.  Co-Design of Matching Sub-Networks to Realize Broadband Symmetrical Doherty With Configurable Back-Off Region , 2020, IEEE Transactions on Circuits and Systems II: Express Briefs.

[20]  S. Koul,et al.  Reconfigurable and Concurrent Dual-Band Doherty Power Amplifier for Multiband and Multistandard Applications , 2017, IEEE Transactions on Microwave Theory and Techniques.

[21]  Marco Pirola,et al.  A 4-W Doherty Power Amplifier in GaN MMIC Technology for 15-GHz Applications , 2017, IEEE Microwave and Wireless Components Letters.

[22]  Peng Chen,et al.  Analysis of Gain Variation With Changing Supply Voltages in GaN HEMTs for Envelope Tracking Power Amplifiers , 2019, IEEE Transactions on Microwave Theory and Techniques.

[23]  S. Y. Nusenu,et al.  Harmonic‐tuned continuum mode active load modulation output combiner for the design of broadband asymmetric Doherty power amplifiers , 2019, IET Microwaves, Antennas & Propagation.

[24]  Y. Guo,et al.  High‐efficiency Doherty power amplifier with wide OPBO range for base station systems , 2019, IET Microwaves, Antennas & Propagation.

[25]  A. R. Dehqan,et al.  Floating Bulk Cascode Class-E Power Amplifier , 2019, IEEE Transactions on Circuits and Systems II: Express Briefs.

[26]  O. Garcia,et al.  Efficient and Linear Power Amplifier Based on Envelope Elimination and Restoration , 2012, IEEE Transactions on Power Electronics.

[27]  J. Rollett.  Stability and Power-Gain Invariants of Linear Twoports , 1962 .

[28]  Ali Medi,et al.  A highly efficient class-EF2 power amplifier in GaAs pHEMT technology , 2017 .

[29]  Yuanan Liu,et al.  Broadband Filtering High-Efficiency Doherty Amplifier Based on a Novel Post-Matching Network , 2019, 2019 European Microwave Conference in Central Europe (EuMCE).

[30]  Zoya Popovic,et al.  Multi-level supply-modulated Chireix outphasing for LTE signals , 2017, 2017 IEEE MTT-S International Microwave Symposium (IMS).

[31]  Marco Pirola,et al.  Design of an 87% Fractional Bandwidth Doherty Power Amplifier Supported by a Simplified Bandwidth Estimation Method , 2018, IEEE Transactions on Microwave Theory and Techniques.

[32]  Z. Popović,et al.  Supply Modulation Behavior of a Doherty Power Amplifier , 2021, IEEE Journal of Microwaves.

[33]  Xinbo Ruan,et al.  Series–Parallel-Form Switch-Linear Hybrid Envelope-Tracking Power Supply to Achieve High Efficiency , 2017, IEEE Transactions on Industrial Electronics.

[34]  O. V. Varlamov,et al.  EER power amplifier modulator efficiency improvement using PWM with additional sigma-delta modulation , 2018, 2018Systems of Signal Synchronization, Generating and Processing in Telecommunications (SYNCHROINFO).

[35]  Slim Boumaiza,et al.  Doherty Power Amplifier With Extended Bandwidth and Improved Linearizability Under Carrier-Aggregated Signal Stimuli , 2016, IEEE Microwave and Wireless Components Letters.