A Novel High Suppression Multilayer Frequency‐Selective Surface Based on Hexagonal Grids

ABSTRACT This paper addresses the issue of achieving excellent overall performance for frequency selective surface (FSS) radomes. A dual‐layer frequency selective surface based on a hexagonal structure is proposed, which offers broadband suppression, roll‐off characteristics, angular stability and a low insertion loss passband. The proposed FSS unit consists of two dielectric layers and a PMI foam layer, with conductive layers placed on both sides of the PMI foam. The FSS is composed of hexagonal ring units and three‐level sub‐centre units. This design achieves broadband suppression from 2 to 20 GHz, while maintaining a flat passband between 7.59 and 8.71 GHz, corresponding to a relative bandwidth of 10.8%. The transmission characteristics remain stable with incident angles ranging from 0° to 50° under both TE and TM modes. To validate the feasibility of the FSS design, a physical prototype was fabricated and tested. The experimental results show that the FSS performs well in broadband suppression, roll‐off characteristics, flat passband and angular stability, in agreement with the simulation results. This demonstrates its strong overall performance and promising potential for applications in stealth antenna radomes.