Linearity enhancement of 0.5μm E/D pHEMT class E power amplifier for PCS applications

摘要

This paper presents a monolithic power amplifier (PA) using 0.5μm enhancement pseudomorphic high-electron mobility transistor (E/D pHEMT) technology with builtin linearizer circuit. Integrated series diode and pHEMT switch linearizer with classE PA is designed. Two tone analysis and Envelope analysis are done to find the IMD3 and ACPR for the circuit with CDMA IS-95 modulated source. As the modulation becomes complex for the future transmission standards, distortion measurement replaces two tone signals with modulated signal (NB-CDMA). The simulated results for a diode and transistor linearizer circuit with two stage class E PA has improvement in IMD3 reduction to 5dBc and 14dBc. The AM-AM simulation for linearizer with diode and transistor appears linear for an input power of 4dbm and 14dBm respectively. ACPR measurement improved to -22dBc and -26dBc respectively.