3D Band-Stop Frequency Selective Structure Based on Slow-wave Structure

The paper describes a design for a low-cost 3D band-stop frequency selective structure (FSS) that is loaded with a slow-wave structure. The FSS unit-cell is made up of two parallel plate waveguides (PPWs) that are stacked on top of each other. One of the PPWs is filled with air while the other is filled with a low-cost substrate with a dielectric constant of 3.66. Instead of using a high-cost substrate with a high dielectric constant, the slow-wave structure is loaded with metallic vias inside the substrate. The proposed FSS exhibits a stop-band from 5.16 GHz to 8.16 GHz, which represents a 45% fractional bandwidth. Additionally, the FSS has been shown to have stable oblique incidence performance.