Triple Bandstop 2.5D Frequency Selective Surface for Sub-6 GHz 5G Communication

The design of a miniaturized triple bandstop frequency selective surface (FSS) is presented for 5th generation (5G) communication systems. Meander lines in a spiral shape have been etched on the top and bottom of a dielectric substrate. To increase the electrical length of the FSS, the spirals are interconnected using four vias at the edges. The proposed design with a 5.2 × 5.2 mm² footprint exhibits a triple bandstop response at sub-6 GHz frequency bands NR n46, LTE 42/LTE43, and LTE 46. The design is simple and cost-effective. As a miniaturized structure with rotational symmetry, it manifests polarization-independent characteristics with a stable frequency response for normal and oblique incident angles up to 84° (simulated) and 60° (measured). The transmission characteristics are verified using simulation and experiments. The proposed design can be used to shield 5G operational devices.