Instabilities in Varactor Multipliers

Operating instability and spurious oscillations are principal factors preventing widespread success with varactor frequency multipliers. This paper outlines a theory of multiplier instability which relates universal characteristics of non-linear resonant circuits to the observed behavior of varactor multipliers and multiplier chains. Design criteria and test methods for stable multipliers are developed; their validity is supported by data on multipliers shown to be stable over wide variations in environment, drive level and load.