Broadband high PAE GaN push-pull power amplifier for 500MHz to 2.5 GHz operation

A broadband push-pull power amplifier with power added efficiency (PAE) greater than 47% from 500 MHz to 2.5 GHz is reported. The power amplifier comprises two GaN integrated circuits whose outputs are combined with a broadband balun to achieve power up to 20W. Each IC contains two stacked GaN HEMTs and is designed to employ a load impedance of 25Ω without any reactive matching in order to achieve broadband operation. To provide a better input impedance match to 25Ω and to reduce gain variation over frequency, an RC feedback network is used. Measurements, under CW excitation, demonstrated greater than 63% power added efficiency at select frequencies and greater than 47% over the entire bandwidth.