Single and multiple Gunn diode oscillator using an image NRD guide

A single and a multiple Gunn diode oscillator using an image NRD guide have been investigated. The LSM/sub 01/ mode which is the operating mode of the image NRD guide can be the dominant mode because undesired modes are suppressed due to existence of the image plane. In experiments at X-band for oscillators with Gunn diodes mounted in the dielectric strip of the image NRD guide, the oscillation frequencies could be varied by a movable shorting plane for the single diode case and an effective power combining operation was obtained for the double diode case.