Design Study of 100GHz Photonic Crystal Reflex Klystron

High order mode reflex klystron is employed to demonstrate the possibility of realizing the miniaturized high frequency vacuum devices. If we are able to oscillate a cavity´s high order mode (ex. TM_mn0) using multi-beam, the output power will be increased m times n times and also the cavity size becomes larger at the same frequency, which makes the circuit fabrication easier and provides a higher power capability. A photonic crystal cavity is adopted for high order mode reflex klystron resonator, in which TM_mn0 mode can be stably supported and coupled to an external system without distortion of the high order resonance mode. In this case, the high order TM_mn0 mode interact dominantly with the multiple electron beams.