Wideband Phase Modulator MMIC for K-Band Supply-Modulated Power Amplifier Linearization

A GaAs MMIC phase modulator with an RF bandwidth from 15 to 30 GHz and a modulation bandwidth of dc to 1 GHz is described. The phase modulator is designed for supply-modulated power amplifier linearization, and its dynamic modulation performance is characterized. From 15 to 25 GHz the circuit achieves a frequency-stable peak phase variation of (42 ± 2)° for modulation signals with instantaneous bandwidths ranging from dc to 50 MHz, with an insertion loss below 3.2 dB.