Reflex klystron using high order mode of photonic crystal cavity

Summary form only given. In this paper, we propose another type of vacuum device that can be a potential application of the photonic crystals. Just like the demonstrated high order TE mode operation, a high order TM/sub mno/ mode in a rectangular cavity can be dominantly interacted with a linear electron beam by using the PBG effect. Therefore, by making beam tunnels at the center of each peak of the electric field, a novel type vacuum device with multi-beam lines can be made. A novel reflex klystron utilizing the photonic crystal cavity is under study for a promising candidate for a compact RF source with relatively high power at the millimeter and sub-millimeter wave range. The detailed physical properties of the high order mode photonic crystal cavity and the beam-wave interaction at the high order TM/sub mno/ mode will be discussed with some experimental results.