Design and Validation of a Concurrent Dual-Band 1.84/2.65 GHz GaN Doherty Power Amplifier

This paper introduces a dual-band Doherty power amplifier (DB-DPA), using symmetrical GaN HEMT devices. The load modulation network incorporates a wideband Doherty combiner followed by a Chebyshev transformer as a post-matching network. The operating frequencies of the proposed DB-DPA are 1.84 and 2.65 GHz with a bandwidth of 70 MHz in each band. The DB-DPA showcases satisfactory performance with a peak output power of 47.4 dBm for 1.84 GHz and 47.1 dBm for 2.65 GHz. Furthermore, a drain efficiency of 50.4-64.5% and 44.4-64.4% is measured between 6-dB output back-off (OBO) level to peak power level, respectively, for 1.84 GHz and 2.65 GHz bands. Concurrent dual-band performance of the proposed DB-DPA is demonstrated using 20-MHz signals with a peak-to-average power ratio of 6 dB. For an average output power of 40 dBm, the DB-DPA yields 46.4% efficiency with an adjacent channel leakage ratio (ACLR) better than -51 dBc.