An Open Structure 600 GHz Mixer with Broadband IF Output Coupling

A quasi-optical broadband Schottky-diode mixer for submillimeter wave-lengths has been realized. In comparision to former approaches emphasis has been laid on the design of the RF choke structure in order to increase the bandwidth of the IF output coupling. An optimization of the mixer has been carried out at IF and RF frequencies (0-20 GHz and 500-650 GHz respectively) using an equivalent circuit diagramm. The results of the simulations and the measurements in the IF range show an exceptional broad IF bandwidth and the simulation at RF frequencies shows that a short is transformed into the diode plane resulting in a maximum RF power converted in the diode. The RF measurements were carried out between 550 GHz and 600 GHz. Operating as a videodetector a maximum sensitivity of 100 V/W has been achieved. In mixer operation a minimum conversion loss of 13.5 dB was measured.