Double-Curved Conformal Bandpass Frequency Selective Surface for Radome Applications

This article introduces a novel mapping technique for uniform placement of unit cells on a double-curved frequency selective surface (FSS) and subsequently demonstrates its efficacy by developing a paraboloid-shaped bandpass FSS for radome applications. A complementary circular Jerusalem Cross has been considered as the constituent unit cell design, which exhibits a narrowband response at 10 GHz with an insertion loss of 0.4 dB. The unit cells have strategically been placed on the curved surface using the developed technique, and its full-wave response has been determined by exploiting the finite element boundary integral (FEBI) method. Afterward, the structure has been fabricated using a 3-D printer, whose measured responses exhibit strong coherence with the simulated results, as well as maintaining an angularly stable performance up to an incident angle of 75°. The proposed mapping technique establishes a unique pathway for developing nonplanar or conformal FSS geometries for various electromagnetic (EM) applications.