Analysis of Varactor Frequency Multipliers for Arbitrary Capacitance Variation and Drive Level

Varactor frequency multipliers have found considerable application for generating microwave signals for receiver local oscillators, parametric amplifier pumps, and other applications. Penfield and Rafuse 1 have analyzed many multipliers under the assumption that a nominally driven abrupt-junction diode is used. For practical multipliers this assumption often does not hold because the junction is not abrupt and is driven into forward conduction. Greenspan2 has analyzed the nominally driven graded-junction doubler, and Davis3 has given an analysis of the overdriven doubler for various capacitance functions. This paper gives a general analysis of lossy varactor frequency multipliers. The theory applies to multipliers with any rational ratio of output to input frequency, any idler configuration, and any capacitance variation of the diode. A computer program was written for evaluating the results up to a X10 multiplier, and results are given for the doubler, tripler, quadrupler, quintupler, sextupler and octupler for different drive 675