Quartz Microstrip Radial Disk Fundamental and Second Harmonic mmW Gunn Oscillators

Microstripline Gunn oscillators have been successfully constructed up through the W-Band (75 - 110 GHz) region employing soft substrate materials. Most designs employ low Q resonators which yield correspondingly poor stability and noise. A new design which exploits the inherently high Q of a radial disk geometry has been successfuly realized in quartz microstrip medium. A GaAs fundamental mode radial disk design has delivered 150 mW output power in the upper Ka-Band (26.5 - 40 GHz) region with essentially no optimization thus far. The fm noise to carrier ratio was better than -89 dBc/Hz at 100 kHz offset frequency. A second harmonic design, which operates fundamentally in Q-Band (33 - 50 GHz), produced approximately 0.5 mW at W-Band (75 - 110 GHz) with an fm noise to carrier ratio better than -80 dBc/Hz at 100 kHz offset. An InP fundamental mode microstrip design operating in W-Band (75 - 110 GHz) produced 15 mW at 94 GHz. A similar design with tighter coupling exhibits an electronic tuning range of 2.2 GHz (centered at 96.6 GHz) with bias pushing, and a power output between 5 mW (min.) and 8.8 mW (max.) over this bandwidth. One circuit was scaled to 101 GHz and produced 4.4 mW with an fm noise to carrier ratio of -79.3 dBc/Hz at 100 kHz offset with a measured loaded QL of 420. Varactor tuning designs are presented for both parallel and series geometries in quartz based microstrip medium.