A Zero-Voltage-Switching Contour-Based Outphasing Power Amplifier

Abstract

A parallel class-E modified Chireix outphasing power amplifier (PA) that can maintain high efficiency across a wide output power range is presented. The architecture presented essentially implements a zero voltage switching (ZVS) contour-based PA using a modified Chireix outphasing structure. It utilizes the inherent load modulation present in the outphasing scheme and combines it with duty cycle modulation to satisfy ZVS conditions over a wide range of output powers. Thus, a ZVS contour-based PA is realized, and the amplifier maintains high efficiency for about 9-dB back-off of output power. Beyond the 9-dB range, simple outphasing is performed to extend the dynamic range up to about 30 dB. The proposed PA, implemented using discrete components on an FR4 printed circuit board, achieves a dynamic range of 30 dB with a peak power of 29 dBm and a peak drain efficiency of 65% at about 6-dB back-off from the peak output power at 100 MHz from a 3-V supply.