High-Power High-Efficiency GaN HEMT Doherty Amplifiers for Base Station Applications

James WONG

IEICE TRANSACTIONS on Electronics   Vol.E104-C    No.10    pp.488-495
Publication Date: 2021/10/01
Publicized: 2021/02/24
Online ISSN: 1745-1353
DOI: 10.1587/transele.2021MMI0003
Type of Manuscript: Special Section INVITED PAPER (Special Section on Microwave and Millimeter-Wave Technologies)
Doherty amplifier,  asymmetric,  inverted,  broadband,  GaN HEMT,  efficiency,  

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In this paper, the high-power high-efficiency asymmetric Doherty power amplifiers based on high-voltage GaN HEMT devices with internal input matching for base station applications are proposed and described. For a three-way 1:2 asymmetric Doherty structures, an exceptionally high output power of 1 kW with a peak efficiency of 83% and a linear flat power gain of about 15 dB was achieved in a frequency band of 2.11-2.17 GHz, whereas an output power of 59.5 dBm with a peak efficiency of 78% and linear power gain of 12 dB and an output power of 59.2 dBm with a peak efficiency of 65% and a linear power gain of 13 dB were obtained across 1.8-2.2 GHz. To provide a high-efficiency broadband operation, the concept of inverted Doherty structure is applied and described in detail. By using a high-power broadband inverted Doherty amplifier architecture with a 2×120-W GaN HEMT transistor, a saturated power of greater than 54 dBm, a linear power gain of greater than 13 dB and a drain efficiency of greater than 50% at 7-dB power backoff in a frequency bandwidth of 1.8-2.7 GHz were obtained.