SIS mixer in 3-port approximation from an experimental I-V curve

Abstract

Conversion efficiency and output conductance are calculated on the basis of an experimental I-V characteristic of a lead alloy tunnel junction in the 3-port approximation considering both the junction capacitance and the quantum reactance. Gain is found only when the reactances are nearly completely tuned out, otherwise loss of at least 7 dB is expected under usual practical conditions. The calculations have been carried out for local oscillator frequency of 88 GHz in the limit of low intermediate frequency.