A C-band GaAs Doherty Power Amplifier MMIC with Compact Size and 1-GHz Bandwidth

Abstract

This paper presents a fully integrated C-band Doherty power amplifier (DPA) in 0.25-um GaAs pHEMT process. The inductive component number and inductance values in the output network of the DPA are minimized, which reduces the chip size significantly. The input matching is optimized in the large signal region for both main power amplifier (PA) and auxiliary PA to achieve higher efficiency and output power. The performance of DPA is enhanced by using an uneven input splitter to deliver more power to main PA. The fabricated DPA exhibits a bandwidth of 1 GHz, with the chip area of only 1.8 mm × 2.2 mm. In the frequency range of 4.6 GHz to 5.6 GHz, the DPA realizes a saturation output power of 29.8 dBm – 31 dBm, a peak power-added efficiency (PAE) of 41% – 46%, and a PAE at 6 dB power back-off of 24% – 27%. The small signal gain is higher than 11 dB, in the large bandwidth from 4.5 GHz to 6.2 GHz.