A high performance 2.4 GHz GaAs HBT class J power amplifier

Abstract

A 2.4 GHz GaAs HBT Class J power amplifier (PA) was presented. This paper analyzed the nonlinear output capacitor character of GaAs HBT, and proposed the load impedance design requirement for high performance power amplifier. The nonlinear output capacitor of transistors with a paralleled lumped capacitor off chip was used to improve the performance of Class J PA. The implemented 2.4 GHz Class J PA shows a saturated output power of 29.5 dBm, with a maximum power added efficiency (PAE) of 51.6 %. Compared with the same biased Class AB PA, the output power is improved by 1.3 dB and the maximum PAE is enhanced by 9.2 %.