Transmission properties of A-sandwich radome with Frequency Selective Surface

A-sandwich radome structure with Frequency Selective Surface (FSS) was designed based on a mutual admittance approach, and the experimental objects of planar and conical radome were manufactured, which verified the integral technique of composite structures. Tests on the planar sample and FSS conical radome were carried out in an anechoic chamber, and some of which were compared with computation results. The results show that the dual-layer FSS loaded by A-sandwich structure has a small loss of in-band transmission with flat-peak characteristics, and the incidence angle and polarization of the bandwidth show a good stability. At a large incidence angle of 60°, the difference of -3 dB bandwidth between TE and TM polarizations of a dual-layer FSS is 1. 3 GHz less than that of sigle-layer FSS. When the thickness of honeycomb sandwich layer is large (about 1/4λ), the coupling between the two side FSS layers is little, so dual and single layer FSSs have the same resonant frequency. Furthermore, the transmission properties of the curved FSS radome are related to both antenna polarization and incident direction, and the experimental results of the radome in the main polarization plane are consistent with that of the planar objects. These results indicate that the influence of curvature is quite small in a test of local near-field, so the local planar approximation can be used in the design stage.