Linearised InGaP/GaAs HBT MMIC power amplifier with active bias circuit for W-CDMA application

Abstract

A high linearity InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) power amplifier is demonstrated using a new structure for a bias circuit for wideband-code division multiple access (W-CDMA) application. A one shunt capacitor is added to a novel active bias circuit and acts as a lineariser improving input P-IdB Of 16 dB and phase distortion of 5.1 degrees for the hybrid phase shift keying (HPSK) modulated signal at the 28 dBm output power; the lineariser showing no significant increase of signal loss and chip area. The two-stage HBT MMIC amplifier exhibits a power-added efficiency (PAE) of 37%, a linear power gain of 24.5 dB, and an output power of 28 dBm With an adjacent channel power ratio (ACPR) of -45 dBc, under a 3 V operation voltage.