A compact spoof plasmonic 4-way frequency splitter with band-pass filters

A compact spoof plasmonic 4-way frequency splitter with band-pass filters at microwave frequencies is proposed. The ultrathin metal structure is placed on a dielectric substrate. Each branch of the splitter is composed of periodic metal grating structures and the groove depth of each branch is different. To make the structure more compact, the meander grooves are introduced for the branch with deepest grooves. To improve the isolations between branches at lower frequencies, the band-pass filters composed of I-shaped grooves are introduced at front of some branches. The simulation results show that electromagnetic waves at different frequency are guided and propagate along different branch on the proposed plasmonic frequency splitter. Good isolation between branches can be observed.