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

New design method of push‐push oscillators is proposed using harmonic load‐pull simulation to determine optimum load impedances at both fundamental ( f 0 ) and second harmonic frequencies (2 f 0 ). It allows high output power at 2 f 0 while meeting oscillation condition at f 0 . 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 ( f max ) 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 f max 's.