EH-impedance tuner with dielectric-based backshorts for millimetre wave diode testing

In this paper, we present a waveguide EH-impedance tuner utilizing dielectric-based backshorts. The tuner is directly machined and the used design can be easily integrated in a waveguide block with other waveguide components. The tuner offers low losses, excellent input impedance coverage and accurate tuning over the frequency range of 140 - 190 GHz, where the maximum measured reflection coefficient is 0.92 (VSWR = 24) at 148 GHz. Our tuner is designed to be a part of a millimetre wave diode testing platform, but it can also be used as a normal stand-alone tuning device in many millimetre wave applications. Design is validated with G-band (140 - 220 GHz) measurement results.