A Compact Surface Plasmonic Band-Pass Filter with Sharp Out-of-Band Rejection

We propose a compact band-pass filter based on spoof localized surface plasmons (LSPs), which consists of four rectangular metal rings with corrugated grooves. It has been shown that the couplings between the resonators produce the flat-top transmission response and sharper out-of-band rejection. The simulation results validate the functionalities. It is believed that the proposed filter could be applied in the high-performance circuit design with compact size.