A 180–196 GHz image‐reject Schottky‐diode MMIC mixer

This article describes a novel single‐sideband, Schottky diode integrated circuit mixer. The subharmonically pumped mixer, operating on the 4th local oscillator (LO) harmonic, was developed for use in millimeter‐wave receiver and transmitter applications in the 180–196 GHz band. The gallium arsenide (GaAs) monolithic microwave integrated circuit (MMIC) was fabricated using a standard commercial process. This is the first time a fully integrated, 4th harmonic image reject mixer has been reported in this frequency range. The mixer operates with a fixed pump frequency of 47 GHz (corresponding to an LO of 188 GHz) and pump power level of +18.7 dBm. For RF signals in the range 180–196 GHz, the conversion loss is typically 21 dB over the 1–8 GHz IF corresponding to the desired sideband. Under these conditions, high rejection of the undesired sideband is achieved. The rejection is typically >15 dB, over the same IF frequency range, relative to the desired signal.