A Combined 380 GHz Mixer/Doubler Circuit Based on Planar Schottky Diodes

The design, fabrication and test of a combined sub-millimeter wave mixer/doubler featuring a 380 GHz sub-harmonic mixer and a 190 GHz frequency doubler on a single quartz based microstrip circuit is reported in this letter. The integrated circuit uses separate flip-chip mounted planar Schottky diode components to perform the two functions. Measurements give best double sideband mixer noise temperatures of 1625 K at 372 GHz, and a corresponding mixer conversion loss of 8 dB. The measured fixed-tuned radio frequency bandwidth extends from 368 to 392 GHz, in good agreement with simulations. This work represents the first demonstration of a single substrate combined submillimeter wave mixer/doubler.