Study on a W-Band U-shaped Microstrip Meander-line Slow-wave Structure

A W-band U-shaped microstrip meander-line (MML) slow-wave structure (SWS) for traveling-wave tube (TWT) was designed and simulated in this work. The selection of materials used for the dielectric substrate in the SWS was discussed. Meanwhile, to improve the interaction impedance of the SWS, a new structure named conformal dielectric substrate was proposed. According to particle-in-cell (PIC) simulation results, the proposed structure was able to reach an output power of 28.86 W at 96 GHz, with the corresponding maximum gain of 23.8 dB. The 3 dB bandwidth was 7 GHz from 92 GHz to 99 GHz.