A Resistive ink based Circular Swastika-Shaped Radar Absorbing Structure for Stealth Application

This study presents a design for a radar-absorbing structure that has a combo of circular and swastika-shaped surface designs capable of absorbing X and $K u$ bands. The structure has been created using a specifically developed resistive material with an outer layer resistance of $210 \Omega / \square$, while the substrate material used is Roger RO3003 laminate. A metallic plate (copper) has been used for the bottom layer. The proposed structure has been designed and simulated for its performance. The result showed a minimum of 10 dB reflection loss (90% absorption) over $8-20 \mathrm{GHz}$, covering X, Ku, and a portion of the K band. The structure has a fractionalbandwidth (FBW) of 85.71%, with a $0.102 \lambda R$ ($\lambda R$ is the corresponding wavelength to maximum reflection) intermediate layer thickness. The structure has angular stability of up to 50 degrees and polarization insensitivity of up to 90 degrees. The study also examines the performance of power loss and surface current distribution in the structure. It is slim in its architecture and can be fabricated using a customized surface resistive ink, making it an ideal candidate for the aero-stealth application.