Design of High Efficiency Ka-Band Harmonically Tuned Power Amplifiers

Paper i proceeding, 2009

A harmonically tuned power amplifier (PA) design approach is presented to provide high efficiency performance at Ka-band using a GaAs mHEMT device technology. A single-stage monolithic-microwave integratedcircuit (MMIC) class-AB PA is designed and measured. The PA efficiency is optimized for a circuit topology which allows harmonic load impedance terminations up to the third harmonic. An output power of 14 dBm is measured with a small-signal gain of 14 dB and a maximum poweradded- efficiency (PAE) of 43%. Good agreement between measurement and simulation results is observed which allows further investigations through harmonic load-pull simulations using the in-house large-signal model of the device. It is shown that the PAE can be further increased to 50% by more careful second and third harmonic load impedance terminations.