Performance and Stability of Schottky Barrier Mixers

Abstract

We discuss the performance of a Schottky barrier diode as a mixer when the barrier of the diode is open‐circuited at the harmonics 2ωo, 3ωo, etc. of the pump frequency ωo. Such a mixer is shown to be capable of arbitrarily high conversion gain provided where ωc is the cutoff frequency of the diode and η is a parameter that is typically less than 6.25 and approaches 4 under certain ideal conditions. It is shown that the limit imposed by the series resistance of the diode on the double‐sideband noise figure of the mixer is given by An experiment is described at 1.25 GHz on a room temperature mixer whose double‐sideband noise figure Fm as a function of gain has a minimum of about 0.7 dB (for gain less than unity) and a maximum of about 2.3 dB (for high gain).