Compact effective surface plasmon polariton frequency splitter based on substrate integrated waveguide

In this paper, we present a compact effective surface plasmon polariton (ESPP) frequency splitter induced by structural dispersion in substrate integrated waveguide (SIW). The frequency splitter consists of three SIW layers. Periodic wire arrays are placed on the interface of layers with relative effective permittivity in the opposite sign to support ESPP propagation, which can introduce transmission zero. By properly placing the substrates, the two passbands are spatially isolated from each other. The designed frequency splitter is numerically simulated and analysed. The numerical results demonstrate that the two passbands can be flexibly tuned by changing the relative permittivities of substrates and the lateral dimensions of SIW. The sample design achieves tunable dual passbands split and has a low profile and compact size.