Design and performance of MESFET, HBT, and PHEMT power amplifiers

Abstract

The design and performance of MESFET, HBT, and PHEMT power amplifiers that have established state-of-the-art benchmarks for power output, power density, bandwidth, linearity, and efficiency is reported. The off-chip output match MESFET MMIC amplifier has demonstrated 24 Watts /spl plusmn/1.3 dB from 3.0 to 6.0 GHz, with a maximum power output of 33-Watts, at power-added efficiencies of 25% to 41.5%. The HBT MMIC amplifier covers 6 to 10 GHz and produces 1.25 to 2.15 Watts at 30% to 46% power-added efficiency. As a linear amplifier, this MMIC has demonstrated less than 0.8 dB differential between single and two tone saturated power with -15 dBc IMD, and -30 dBe IMD at 5 dB back-off from 2 dB gain compression. The internally matched PHEMT amplifier in single chip form has demonstrated 5 Watts at 50% power-added efficiency with 13 dB of power gain in the 3.7 to 4.2 GHz SATCOM band. At a two-tone output power of 3.5 Watts the IMD is -15 dBc, improving to -26 dBc at 5 dB back-off. The four chip units have achieved 20 Watts at 44% power-added efficiency with 13 dB of power gain.