Self-injection locked NRD guide Gunn oscillators using cost-effective metal rod resonator at 60 GHz

From the viewpoints of cost-effectiveness and fabrication accuracy, the reflection type of self-injection locked NRD guide Gunn oscillator using a metal rod resonator with an unloaded Q-factor of about 1300 has been investigated. In the first place, the first higher order mode of the metal rod transmission line was focused as the resonant mode due to applying the reflection type of self-locking scheme, and the diameter of the metal rod was decided by calculating the cutoff frequency and the unloaded Q factor. Next, the unloaded Q factor was measured and the theoretical consideration was confirmed. The oscillation and phase-noise characteristics of the oscillator using the metal rod resonator were evaluated in the theoretical and experimental investigation. From the results, it was confirmed that the oscillation performance was almost the same as that of the reflection type of self-injection locked NRD guide Gunn oscillator using a ceramic resonator.