1.9GHz band highly linear 2-stage power amplifier MMIC based on InGaP/GaAs HBT

Abstract

This paper describes a highly linear two-stage power amplifier monolithic microwave integrated circuit (MMIC) for the 1.9GHz band based on InGaP/GaAs heterojunction bipolar transistor (HBT). For achieving the highly linear power amplifier, the active biasing circuits have been optimized for the 1 st -and 2 nd -stages' third-order intermodulation distortion products (IMD3s) by cancelling them each other. Based on the optimized circuit parameters, the twostage power amplifier MMIC has been designed and fabricated to verify the cancellation effect over the 1.9GHz band. The fabricated MMIC exhibits a high third-order intercept point (OIP3) of 48dBm at an output power of 25dBm, an output power at 1dB compression point (P1dB) of 30dBm, a high PAE of 35.8% at P1dB, and a gain of 28.5dB under a supply voltage of 5V and a quiescent current of 345mA.Index Terms -Power amplifier, MMIC, InGaP/GaAs HBT, active bias circuit, IMD3.

A fully integrated GaAs HBT power amplifier with enhanced efficiency for 5-GHz WLAN applications

“…As the bias point of transistors changes significantly with input power, the design of a bias circuit is one of the keys to obtaining sufficient output power with high linearity [25,26,27,28]. Fig.…”