Development of counter-streaming two beam oscillator

Summary form only given. We propose a novel oscillator using two electron beams reversely traveling for high frequency applications, particularly in the millimeter/sub-millimeter region. In the oscillator, the electron beams interact with high-Q reentrant cavities coupled through coupling-slots The counter-streaming electron beams mutually talking through the coupled-cavities thus compose the internal feedback, based on a noise seed induced by the electron beams. The parallel coupled-cavity is geometrically investigated to optimize the circuit dimensions in the Ka-band. The optimum coupled-cavity respectively has 29.92 GHz and 31.95 GHz of eigen frequencies at Δφ=0 and Δφ=π, where Δφ is the phase shift per cavity. The start oscillation current of this novel device is about twice as low as that of a conventional two-cavity oscillator with external feedback. The start oscillation current reduction in this novel device provides the possibility of higher frequency applications.