E-plane Waveguide Bandpass Filter based on Double-Layer Spoof Surface Plasmon Polaritons

In this paper, a novel design method of bandpass filter (BPF) using the high-order modes of spoof surface plasmon polaritons (SSPPs) is proposed. With the proposed design method, an E-plane waveguide BPF is specifically designed, which contains two metallic layers with different metallic patterns coated on the front and back sides of a printed circuit board (PCB) and tightly coupled with each other. The high-order mode dispersive characteristics of SSPP unit cell can be effectively adjusted by changing the dimensions of the patterns, allowing control over the upper and lower cut-off frequencies of the proposed BPF. Good simulated filtering performance of the E-plane waveguide BPF verifies the potential and feasibility of the proposed design method for millimeter-wave applications.