Design of a dielectric-based tunable waveguide backshort

This paper describes a dielectric-based tunable waveguide backshort and precision tuning mechanism for it. It also gives measured and simulated results for a W-band backshort and simulated results for different materials, material thicknesses, frequency ranges and for material tapering. This backshort is low-loss, reliable, and easy to design and fabricate. Furthermore, it has the most accurate tuning compared to other waveguide backshorts making it suitable for submillimetre-wave applications. Furthermore, it does not suffer in-band resonances. The measured return loss for the W-band (75-110 GHz) backshort using a quartz slab is less than 0.21 dB.