A new metasurface-assisted ultra-wideband window for a gyro-travelling-wave tube

A cylindrical-pillar-based new meta-surface-assisted ultra-wideband window is proposed, designed and simulated, in the present paper, for a wideband gyro-traveling-wave tube. The return-loss characteristics were analyzed by simulation in a high-frequency structure simulator to calculate the bandwidth at an allowable return loss of −17 dB and the center frequency of 44.42 GHz of the operating bandwidth of 32.10 GHz (28.31–60.47 GHz) which is 72.26% relative bandwidth for the operating circular TE0, 1 mode. The results with respect to which parameters/characteristics were validated within 5% against those obtained using CST Microwave Studio. The sensitivity analysis was also carried out to obtain the manufacturing tolerances. Interestingly, an improvement of 8.03% (from 64.23% to 72.26%) at an allowable return-loss of −17 dB was obtained in the proposed window over the bandwidth achieved in previously reported square-pillar with cylindrical-tip-based meta-surface-assisted window.