Stabilisation of millimetre wave oscillators

A novel tuneable quasi-optical scheme is presented to provide stabilisation of both fundamental and second-harmonic oscillators at W-band, with excellent isolation from the load. A decrease in phase noise by more than 4dB on free-running Gunn oscillators at 90 GHz is demonstrated with SSB phase noise better than -120 dBc/Hz at 100 kHz away from the carrier. This is believed to be state of the art.<
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