Experimental investigations on miniaturized vacuum electron devices

We investigated foundations for high frequency vacuum electron devices, experimentally with emphasis on LIGA (deep etch X-ray lithography: lithographie, galvanoformung, abformung; German acronyms) to fabricate a miniaturized interaction circuit and a photonic crystal (PC) resonator to excite a stable high order mode. The successful operation of a LIGA-fabricated folded-waveguide traveling-wave tube was reported. From the physical considerations such as Debye length and photonic band gap, we proposed a reflex klystron adopting a cold cathode and a PC resonator.