Meta-Surface-Assisted High-Power Broadband Rectangular TE1,0 Mode Window for Vacuum Electronic Devices

Window design in overmoded waveguides that achieves both broadband and high power is a challenge in the vacuum electronic devices. Here, a broadband overmoded meta-surface-assisted window (MAW) is designed using the equivalent medium theory. The distribution of the dielectric is designed according to the characteristics of the transmission mode electric field, thereby exhibiting good broadband matching characteristics, with an extreme bandwidth of 54.5% (24–42 GHz) in an overmoded rectangular waveguide. The generation and suppression methods of ghost mode caused by overmoded, processing tolerance, and thermal power handling capability are discussed. The cold test verifies the feasibility with the real relative bandwidth exceeds 40%, providing a reference for realizing the broadband high-power overmoded output window of vacuum electronic devices.