Cylindrical 3-dimensional model of a Gunn oscillator

A three-dimensional model of a dielectric-encapsulated X-band Gunn oscillator in a coaxial microwave cavity is analyzed for interactions between cavity and device and between package and device, for the physical behavior of the device, package, and cavity, surface charge effects, and charge carrier transit effects. Model-based predictions of frequencies above the fundamental, cavity-device and package-device coupling, of trapping of high-field domains at the anode, and of the device-current waveform are confirmed. A stationary high-field domain can linger at the anode and suppress Gunn oscillations, so that large doping fluctuations (20% doping notch) are required to support Gunn oscillations. A 23.5% reduction in radial electron field is evidence of perturbation of the electric field by the device package.