Design of high‐power W‐band push‐push oscillators using load‐pull technique

Abstract

New design method of push‐push oscillators is proposed using harmonic load‐pull simulation to determine optimum load impedances at both fundamental (f0) and second harmonic frequencies (2f0). It allows high output power at 2f0 while meeting oscillation condition at f0. In addition, the compact self‐biasing source feedback is proposed using coupled line for negative resistance generation. The proposed method is applied to the design of W‐band high power push‐push oscillator using 0.15 μm GaAs pseudo‐morphic high electron mobility transistors (pHEMTs) with typical maximum oscillation frequency (fmax) of 180 GHz. The measurement shows an output power of 2.2 dBm at 92.3 GHz with a phase noise performance of −84 dBc/Hz at 1 MHz offset frequency. This result corresponds to relatively high output power at this frequency compared with reported oscillators using GaAs HEMTs with higher fmax's.