Design of Filtering Magic-T with Wideband and Wide Stopband Based on HMSIW and Spoof Surface Plasmon Polaritons

A novel filtering magic-T (FMT) with a compact size, broad bandwidth, and wide stopband rejection based on the dielectric-covered L-shaped groove (DCLSG) half-mode substrate integrated waveguide spoof surface plasmon polariton (HMSIW-SSPP) structure is proposed for first time. HMSIW (HMT) dual-layer substrates designed. Then, we construct FMT by periodically etching subwavelength DCLSG SSPP into HMT. The achieves bandpass response nearly 50% reduction of longitudinal dimension attributed to characteristics strong slow-wave property HMSIW-SSPP structure. In addition, beneficial from regulable cut-off frequencies structure, provides impedance bandwidth independently adjustable lower upper passband. Finally, prototype fabricated validate this design idea. measured results illustrate that has 3-dB fractional 40.23% 20-dB up 2.12 f0 (f0: center frequency passband).