Investigation of a Staggered Double-Vane Slow-Wave Structure With a Rectangular Cavity for Terahertz Traveling Wave Tube

A slow-wave structure (SWS) with a new structure is proposed to improve the output efficiency. The SWS operates at a central frequency of 220 GHz. The manufacture is limited to a certain size, and any complexity in shape will inevitably lead to higher fabrication costs. But, in this article, the shape of the additional new structure is simple and easy to process. By introducing a rectangular cavity (RC), the electric field is induced. Due to the acting force in the cavity, the electrons are modulated more completely and ahead of time and the beam-wave interaction is enhanced. At the target frequency, the output power is higher under the same interaction length. According to the particle-in-cell (PIC) simulation, the SWS with a RC shows better output performance under the same length of SWS. Driven by a 23.8 kV, 50 mA electron beam, the amplifier can provide an output power of 63 W when the input signal is 50 mW. The corresponding gain is 31 dB and the electronic efficiency is 5.3%. The 3-dB bandwidth is up to 50.5 GHz.