Monolithic 40-GHz 670-mW HBT grid amplifier

A 36-element monolithic grid amplifier has been fabricated. The active elements are pairs of heterojunction-bipolar-transistors. Measurements show a peak gain of 5 dB at 40 GHz with a 3-dB bandwidth of 1.8 GHz (4.5%). Here we also report comparisons of patterns and tuning curves between the measurements and theory. The grid includes base stabilizing capacitors which result in a highly stable grid. The maximum saturated output power is 670 mW at 40 GHz with a peak power-added efficiency of 4%. This is the first report of power measurements on the monolithic quasi-optical amplifier.