High efficiency and high linearity InGaP/GaAs HBT power amplifiers: matching techniques of source and load impedance to improve phase distortion and linearity

This paper reports on a matching technique of the source and load impedance focused on a phase distortion of InGaP/GaAs HBT power amplifiers to simultaneously achieve a high efficiency and a high linearity performance. Load-pull measurements were done to maximize power added efficiency (PAE) and source pull measurements to minimize the phase distortion and adjacent channel leakage power (ACP). Our HBT exhibited a high PAE of 60.7% and an ACP at a 50 kHz offset frequency of -51 dBc for 1.5 GHz /spl pi//4-shift QPSK modulated signal with an output power (P/sub cut/) of 31 dBm under a supply voltage of 3.5 V.