A second harmonic 77 GHz Gunn diode microstrip oscillator for a vehicle radar, and a laser trimming method using a package aperture

摘要

A Gunn diode 3 is mounted at least partially in a substrate and is coupled to resonator 5 which sets the fundamental oscillation frequency. Features of the planar circuit pattern 4 inhibit transmission of the fundamental frequency but let a second harmonic signal pass to the output port 10. The substrate may be alumina, quartz, aluminium nitride or softboard. The circuit may comprise thick-film, thin-film or microwave PCB conductors. DC bias is fed through bias filter 6. The Gunn diode is preferably a graded-gap device using hot electron injection and is preferably unpackaged. The resonator 5 may be laser-trimmed after assembly, by means of an aperture in the package. Higher harmonics may be used.