A High-Power Low-Distortion GaAs HBT Power Amplifier for Mobile Terminals Used in Broadband Wireless Applications

This paper describes technologies of miniaturized high-power low-distortion GaAs HBT power amplifiers with a low-voltage operation for mobile terminals used in 5-6 GHz broadband wireless applications. In conjunction with diode-based linearizing techniques, wideband matching network techniques including trap circuits for second harmonics allow us to obtain a compact broadband power amplifier module with harmonic filtering, achieving the high linear output power at a low supply voltage together with the low distortion and the low second-harmonic spurious outputs in a wide frequency range. The fabricated power amplifier exhibited linear output power levels of 21 and 22 dBm at EVM values of 2.0 and 3.0%, respectively, measured with 54 Mb/s 64-QAM-OFDM signals at a supply voltage of 3.3 V in a frequency range of 5-6 GHz. Second harmonic spurious outputs below -35 dBc were also attained.