A 70W package-integrated class-E Chireix outphasing RF power amplifier

Abstract

A high-power class-E Chireix outphasing RF power amplifier integrated inside a transistor package is described. The optimum class-E loading conditions and the Chireix compensation elements are provided to the active devices by a dedicated ultra-low loss bondwire-based transformer power combiner that enables a very small form factor and low cost. The realized prototype achieves 70.6 W peak power with 73% peak drain-efficiency at 2.3 GHz, and up to 81% peak drain-efficiency for slightly lower power at 2.2 GHz. When operated for maximum power, it reaches 53.5%/43.5% average drain-/total-efficiency for a 9.6 dB PAR W-CDMA signal at 2.3 GHz with low ACLR1/2 levels (-49/-56 dBc after memory-less DPD).