A Dual-Mode Bias Circuit Enabled GaN Doherty Amplifier Operating in 0.85-2.05GHz and 2.4-4.2GHz /Author=Komatsuszaki, Yuji; Ma, Rui; Sakata, Shuichi; Nakatani, Keigo; Shinjo, Shintaro /CreationDate=June 24, 2020 /Subject=Communications, Electronic and Photonic Devices, Signal Processing

We report an ultra-wideband and high efficiency sub-6GHz power amplifier, which is based on multi-band Doherty load modulation. Key novelty is that a dual-mode bias circuit which operate as frequency-dependent compensating circuit at a half of center frequency 0.5f0 mode, and DC-block and RF-choke at a center frequency f0 mode. The amplifier using 0.15-um GaN HEMT FETs achieved drain efficiency of 41.4-58.2% over 0.85-2.05GHz with 0.5f0 mode, and 43.5-62.1% over 2.4-4.2GHz with f0 mode at 6dB power back-off. This, to the best of authors’ knowledge, is the widest coverage of frequency reported so far for a multi-band Doherty amplifier at these carrier frequency range. It is a very promising PA technology for sub 6GHz base station, enabling reduction of the total cost of ownership (TCO) for operators. IEEE International Microwave Symposium (IMS) This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories, Inc.; an acknowledgment of the authors and individual contributions to the work; and all applicable portions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories, Inc. All rights reserved. Copyright c © Mitsubishi Electric Research Laboratories, Inc., 2020 201 Broadway, Cambridge, Massachusetts 02139 A Dual-Mode Bias Circuit Enabled GaN Doherty Amplifier Operating in 0.85-2.05GHz and 2.4-4.2GHz Yuji Komatsuzaki#1, Rui Ma*, Shuichi Sakata#, Keigo Nakatani#, Shintaro Shinjo# # Mitsubishi Electric Corporation, Information Technology R&D Center, Japan * Mitsubishi Electric Research Laboratories, USA 1 Komatsuzaki.Yuji@bx.MitsubishiElectric.co.jp Abstract— We report an ultra-wideband and high efficiency sub-6GHz power amplifier, which is based on multi-band Doherty load modulation. Key novelty is that a dual-mode bias circuit which operate as frequency-dependent compensating circuit at a half of center frequency 0.5f0 mode, and DC-block and RF-choke at a center frequency f0 mode. The amplifier using 0.15-μm GaN HEMT FETs achieved drain efficiency of 41.4-58.2% over 0.852.05GHz with 0.5f0 mode, and 43.5-62.1% over 2.4-4.2GHz with f0 mode at 6dB power back-off. This, to the best of authors’ knowledge, is the widest coverage of frequency reported so far for a multi-band Doherty amplifier at these carrier frequency range. It is a very promising PA technology for sub-6GHz base station, enabling reduction of the total cost of ownership (TCO) for operators. Keywords— GaN, power amplifier, Doherty amplifier, bias circuit, load modulation.