Nested Circular Ring Based FSS-Composite for Low Observable Aerospace Platforms

This paper describes the electromagnetic design, simulation, and experimental studies of Circular ring-based customized absorber working for broadband frequency 8-21 GHz. The proposed design consists of continuous and split arms-based circular rings associated with four circular arm cut geometry. The proposed absorber has been designed using customized glass fabric reinforced plastics (GFRP) having thickness of 0.2 mm, which is separated to a metallic ground plane (CFRP) by a Roha Cell foam spacer of 2mm. Proposed composite has been designed using customized developed 200 ohms resistive materials, design has been simulated using a full-wave electromagnetic simulator under periodic boundary conditions. The simulation result shows minimum 10 dB reflection loss value (90% absorption) in 8-21 GHz, which covers X, Ku, and some portion of K bands having a full-width absorption bandwidth of 13 GHz with 93% fractional bandwidth (FBW). Further, the proposed absorber design has been fabricated and validated experimentally with the simulated results. The proposed absorber is thinner in nature, polarization insensitive, possesses good angular stability, and features of fabricability using customized substrate. These attributes encompass it for potential usages in aerospace platforms.