Study of a V-band Overmoded Coupled Cavity Travelling Wave Tube

In this paper a coupled cavity Travelling Wave Tube (TWT) working in overmoded condition in the V-band is presented. The structure operates at the TM51 mode. This allows it to work in the V-band while the fundamental mode is in the Q-band. The structure, simulated with CST Studio Suite, works with a cathodic voltage of 33.2 kV and current of 1 A. The output saturation power at 62.75 GHz is 3870 W, reaching an efficiency of 11.6 %. The gain of a structure comprising of 20 periods is 16 dB, and is higher than 12 dB for the whole range of frequency between 62.3 GHz and 62.9 GHz, granting a bandwidth of more than 500 MHz. This structure shows promising results to allow the use of larger structures to operate at higher frequencies.