Study on photonic crystal reflex klystron for millimeter-wave applications

Reflex klystron is employed to demonstrate the possibility of realizing the miniaturized high frequency vacuum devices. To reduce start oscillation current and current density, high order TM
_mno
mode is taken into consideration. Adapting photonic crystal band gap concept, high order mode can be stably supported and coupled to an external system without distortion of the generated mode in the cavity.