Wideband Sequential Circulator Load Modulated Amplifier with Back-Off Efficiency Enhancement

This paper demonstrates a novel power amplifier (PA) architecture; the sequential circulator load modulated amplifier (SCLMA). The sequential configuration resulted in excellent bandwidth and extended back-off efficiency enhancement, making it suitable for modern communication scenarios with large peak-to-average-power-ratio (PAPR) signals. A wideband prototype PA based on GaN transistors and a commercial off-the-shelf circulator is employed to validate the SCLMA concept. The experimental results exhibit a drain efficiency of 55–68 % at the peak output power and 46–53 % at 8-dB output power back-off across 2.0-3.0 GHz. Combined with the measured peak output power of 42.7±0.7 dBm in the same range, make it a promising candidate for use in modern energy-efficient wireless communication transmitters.

[1]  C. Fager,et al.  Design of a Compact GaN Power Amplifier With High Efficiency and Beyond Decade Bandwidth , 2022, IEEE Microwave and Wireless Components Letters.

[2]  C. Fager,et al.  Emulation of Non-Reciprocity applied in Load-Modulated Power Amplifier Architectures using Single Amplifier Load-Pull Measurements , 2022, 2021 51st European Microwave Conference (EuMC).

[3]  R. Hou,et al.  Doherty Load Modulation Based on Non-Reciprocity , 2022, European Microwave Conference.

[4]  C. Fager,et al.  A Generic Theory for Design of Efficient Three-Stage Doherty Power Amplifiers , 2022, IEEE Transactions on Microwave Theory and Techniques.

[5]  C. Fager,et al.  Circulator Load Modulated Amplifier: A Non-Reciprocal Wideband and Efficient PA Architecture , 2021, 2021 IEEE MTT-S International Microwave Symposium (IMS).

[6]  Meng Li,et al.  Analysis and Design of Highly Efficient Wideband RF-Input Sequential Load Modulated Balanced Power Amplifier , 2020, IEEE Transactions on Microwave Theory and Techniques.

[7]  Robert Bogdan Staszewski,et al.  Breaking the Bandwidth Limit: A Review of Broadband Doherty Power Amplifier Design for 5G , 2019, IEEE Microwave Magazine.

[8]  Chao Yu,et al.  Improved Three-Stage Doherty Amplifier Design With Impedance Compensation in Load Combiner for Broadband Applications , 2019, IEEE Transactions on Microwave Theory and Techniques.

[9]  Christian Fager,et al.  Analysis and Design of a Doherty-Like RF-Input Load Modulated Balanced Amplifier , 2018, IEEE Transactions on Microwave Theory and Techniques.

[10]  Paul Saad,et al.  A 1.8–3.8-GHz Power Amplifier With 40% Efficiency at 8-dB Power Back-Off , 2018, IEEE Transactions on Microwave Theory and Techniques.

[11]  Min Zhang,et al.  Broadband Continuous-Mode Doherty Power Amplifiers With Noninfinity Peaking Impedance , 2018, IEEE Transactions on Microwave Theory and Techniques.

[12]  Steve C. Cripps,et al.  An Efficient Broadband Reconfigurable Power Amplifier Using Active Load Modulation , 2016, IEEE Microwave and Wireless Components Letters.

[13]  Renato Negra,et al.  Broadband Sequential Power Amplifier With Doherty-Type Active Load Modulation , 2015, IEEE Transactions on Microwave Theory and Techniques.

[14]  C. Fager,et al.  A Modified Doherty Power Amplifier With Extended Bandwidth and Reconfigurable Efficiency , 2013, IEEE Transactions on Microwave Theory and Techniques.

[15]  W.H. Doherty,et al.  A New High Efficiency Power Amplifier for Modulated Waves , 1936, Proceedings of the Institute of Radio Engineers.