An integrated wide-band varactor-tuned Gunn oscillator

A report is made of a thin-film varactor-tuned Gunn effect oscillator in X band employing unencapsulated diodes. The Gunn device, which is an inverted mesa type, is mounted off the substrate on a copper header and this arrangement can dissipate 7 W without the Gunn device suffering thermal damage. The varactor is a beam-lead silicon p⁺nn⁺IMPATT diode connected in series with the Gunn device. A circulator is integrated with the oscillator to provide load isolation, and tuning ranges in excess of 2 GHz are reported. Good agreement exists between calculated and measured values of oscillator tuning range.