A novel topology with controllable wideband baseband impedance for power amplifiers

Abstract

This paper presents a novel topology to control the baseband impedance of a power amplifier (PA) to avoid performance deterioration in concurrent dual-band mode. This topology can avoid pure resonance of capacitors and inductors LC, which leads to a high impedance at some frequency points. Consequently, it can be applied to transmitters that are excited by broadband signals. In particular, by adjusting the circuit parameters and increasing stages, the impedance of the key frequency bands can be flexibly controlled. A PA is designed to support this design idea. Its saturated output power is around 46.7 dBm, and the drain efficiency is >68.2% (1.8–2.3 GHz). Under concurrent two-tone excitation, the drain efficiency reaches around 40% even under 5.5 dB back-off power with the tone spacing from 10 MHz to 500 MHz. These results demonstrate that the proposed topology is capable of controlling wideband baseband impedance.