Watt-level millimeter-wave monolithic diode-grid frequency multipliers

Monolithic Schottky diode grids have been fabricated on 2-cm/sup 2/ GaAs wafers in a proof-of-principle test of a quasioptical varactor millimeter-wave frequency multiplier array concept. An efficiency of 9.5% and output power of 0.5 W were achieved at 66 GHz when the diode grid was pumped with a pulsed source at 33 GHz. The diode-grid equivalent circuit model based on a transmission-line analysis of plane-wave illumination was verified experimentally over a frequency range of 33 GHz to 140 GHz. In parallel with the diode doubler array studies, the authors investigated the use of an MOS structure having an undoped epitaxial layer, which is grown on a heavily-doped substrate and isolated by a thin oxide layer and a GaAs barrier-intrinsic-N/sup +/ (BIN) diode structure. The thin MOS concept was tested for doubling efficiency (to 95 GHz) for a variety of dot radii as a function of pump power. In support of the monolithic BIN diode array studies, a quasioptical tripler design was developed and tested. Based on the results reported, the authors are confident in predicting watt-level continuous-wave power from a monolithic-diode-grid frequency tripler design using the BIN diode concept.<>