Design of a 380 GHz sub-harmonically pumped mixer based on planar Schottky diodes

This paper presents the design and simulation of a 380 GHz sub-harmonically pumped mixer, based on planar GaAs air-bridged Schottky anti-parallel diodes from Rutherford Appleton Laboratory. The diode was designed and fabricated by millimeter technology group, Rutherford Appleton Laboratory, UK. The mixer circuit is fully integrated with the microstrip circuit and the flip-chipped diode on suspended 50μm thick quartz substrate, its circuit configuration and cavity block are detailed in the paper. Based on ANSOFT's three-dimensional full-wave electromagnetic simulation software HFSS and AGILENT's circuit simulation software ADS, the 380 GHz sub-harmonically pumped mixer's system level modeling is studied. The simulation investigation shows state-of-the-art results obtained. A best conversion loss of 6.5dB is achieved with 3mW LO power at 383 GHz. At that best working frequency, the RF and LO port reflection loss are -14dB and -7dB, respectively. Over RF band of 365-395 GHz, the conversion loss is below 10 dB.