Millimeter Frequency Multiplication with an In-Line Harmonic Generator (Correspondence)

When building a crystal frequency multiplier to generate harmonics in the millimeter region, one may improve conversion efficiencies by one of two basic techniques: selecting an improved nonlinear junction, or improving the physical and electrical environment of that junction. This communication will describe an in-line frequency multiplier designed to facilitate changing semiconductors and whiskers to evaluate their efficacy in generating the third and fourth harmonics of a 22-Gc drive signal. In addition, the test results on several different semiconductors will be presented.