MILLIMETRE-WAVE FREQUENCY DOUBLERS USING GaAs MESFETS.

When it is used as a frequency doubler, the GaAs MESFET will give a second harmonic conversion gain of typically 6 db less than its fundamental. Consequently a device with a realizable fmax of 50 GHz should give a 0 db conversion gain at about 25 GHz. Therefore the combination of a Ku-band FET oscillator plus a FET frequency doubler having a few dbs conversion loss should be capable of producing more power than a fundamental Ka-band oscillator. This article describes the performance of a pair of 15 to 30 GHz balanced frequency doublers. Both use the same 0. 3 mu m gate-length devices though the MESFETs in each are operated under differing conditions in an attempt to establish the best conditions for harmonic generation.