Planar Slow Wave Structures for Millimeter-Wave Vacuum Electron Devices

Planar slow wave structures for vacuum electron devices, such as traveling wave tubes, promise to advance the fabrication of vacuum devices and have therefore attracted interest in the last few years. The increasing operating frequencies of such devices demand manufacturing techniques beyond machining and make planar slow-wave structures particularly interesting. In this paper we introduce two different planar slow wave structures that can be used in traveling wave tube amplifier (TWTA) and backward wave oscillator (BWO). We present simulated results for such devices operating in W-band, although higher frequencies are feasible. The TWTA can achieve a gain of 30.25 dB in the frequency band 82-96 GHz with an output power up to 4.3 W. The BWO can generate a signal with a power of 0.7 W at a frequency of 95 GHz.