Wide-Band Varactor-Tuned Gunn Oscillator

摘要

The present invention relates generally to voltage-tuned oscillators and, more particularly, to a wide-band varactor-tuned microwave Gunn oscillator. Conventional varactor-tuned microwave Gunn oscillator circuits are of microstrip, stripline, coaxial, or waveguide construction in which the biasing and matching is carried out using distributed-type elements. These distributed-type elements are a combination of transmission lines of various impedances whose lengths are appreciable compared to a wavelength at some frequency within the tuning range, typically a quarter wavelength, or multiples thereof, at the center frequency. In addition, conventional circuits utilize Gunn and varactor chips mounted in conventional microwave packages which introduce undesirable parasitic elements. It is generally recognized that distributed circuit elements and package parasitics critically affect the achievable tuning range of varactor-tuned microwave oscillators by reducing the maximum net reactance variation possible for a given change in varactor capacitance. For wide-band tuning, all parasitics must be minimized and the varactor chip must be tightly coupled to the active device and load with non-dispersive and non-distributed coupling elements.