Millimeter-wave self mixing oscillators

A metal waveguide self-mixing oscillator utilizing a coaxial waveguide hybrid circuit was designed, with emphasis on low weight, low cost, and simple construction. Dielectric waveguide technology was applied using a Gunn diode, in a simply constructed cavity, in a self-excited oscillator-mixer mode of operation. Both GaAs and InP Gunn diodes were imbedded in an aperture which was cut in a high resistivity aluminum oxide dielectric waveguide. The significance of the dielectric waveguide technology is that active devices, as well as passive components, can be developed and integrated into circuit modules to construct functional subsystems. Experimental data indicate that the sensitivity of these devices is on the order of -80 dBm which would make them competitive with other conventional mixers. However, these devices have the advantage of having simplified construction with a high signal power burnout level coupled with very low unit cost. These characteristics make the self-mixing oscillator a viable device in low cost receivers, expendable EW sensors, and short range terminal guidance.