A-T FSR Using Modified Double Cross-Slot Bandpass Layer

In the earlier chapters, thin, single-layer rasorber structures demonstrating narrowband absorption characteristics were discussed. Starting with this chapter, the focus shifts toward the development of rasorbers that support broadband absorption. Unlike the narrowband configurations, the broadband rasorber designs utilize multilayered architectures integrated with lossy lumped elements. This chapter introduces a polarization-insensitive A-T frequency selective surface (FSR), where the concepts of wideband absorption and passband transmission are first explored independently and later integrated to achieve the desired absorptive-transmissive behavior. The designed FSR delivers a broad absorption range coupled with a transmission band located at a higher frequency. It maintains stable performance for incident angles up to 30°. The operation of the FSR is examined through an equivalent circuit model (ECM), and its effectiveness is demonstrated through the fabrication and experimental validation of a prototype.