A Ku-band GaN PA with GaAs Gate Modulator for Improved Linearity

A Ku-Band GaN power amplifier (PA) and a GaAs gate modulator are presented. The MMICs work together to amplify signals efficiently while maintaining linearity via gate modulation. In particular, the GaN PA demonstrates a power added efficiency (PAE) greater than 30 %, more than 2W of output power, and a large-signal gain exceeding 13 dB from 11–16 GHz. The gate modulator is designed to extract envelopes with instantaneous bandwidths up to 2 GHz and is measured with a 20MHz LTE signal as well as 2-tone signals with bandwidths up to 800 MHz. The measured PA data is used in an envelope simulator to show IMD3 better than 35 dBc at $\overline {{{\mathbf{P}}_{{\text{out }}}}} = 30{\text{dBm}}$ with gate modulation for a 100MHz 2-tone signal. This represents a 20 dB improvement in IMD3 compared to the static bias case.