A coding based metasurface absorber with triple circular ring resonator for broadband RCS reduction and high EMI shielding effectiveness

Abstract

In this paper, a novel coding-based metasurface absorber (CMA) featuring a triple circular ring resonator is introduced for broadband radar cross-section (RCS) reduction and high electromagnetic interference (EMI) shielding effectiveness. The coding element comprises a triple circular ring resonator generating a 1-bit coding scheme (‘0’ and ‘1’ element) with a reflection phase difference of 180° ± 45° across the frequency range of 7.5 GHz–15.5 GHz by employing varying dimensions for the outer circular ring. A most affordable FR-4 substrate with 1.6 mm thickness is used to design the CMA structure. Binary Particle Swarm Optimization (BPSO) algorithm combined with array theory is employed to strategically position unit cells within the subarray. Simulations demonstrate a significant RCS reduction of −10 dBsm across the entire 7.5 GHz–15.5 GHz band. Furthermore, the 2D and 3D scattering patterns observed at 8.26 GHz, 10.56 GHz, and 13.30 GHz serve as additional proof of the remarkable effectiveness of the optimized pattern in reducing bi-static RCS. The optimized CMA structure also exhibits absorption levels exceeding 80 % at different resonance frequency while maintaining high shielding effectiveness. To validate these findings, a prototype of the optimized CMA structure is fabricated, and experimental investigations are conducted. The measured results closely align with the simulated outcomes, with minor discrepancies observed outside the designated frequency band. Based on comprehensive simulation and experimental analyses, the optimized CMA structure emerges as a promising choice for achieving broadband RCS reduction and high EMI shielding effectiveness in practical applications.