The design of a 310–350-GHz sub-harmonic mixer with planar schottky diodes

This paper presents the design and simulation of a novel fixed-tuned 310-350-GHz wide-band sub-harmonic mixer. The mixer is based on an anti-parallel pair of GaAs Schottky diodes fabricated at European company. The circuits are fully integrated with the RF/IF filter and flip-chipped onto a suspended quartz-based substrate. A best double-sideband-mixer loss of 5.7 dB was achieved with 5 mW of LO power at 332 GHz. Over an RF band of 310-350 GHz, the double-sideband loss is below 11 dB. This state-of-the-art optimization is attributed to lower parasitic devices and a low-loss waveguide circuit.