Low Profile Broadband Wheel Shaped Resistive-FSS Glass Composite for Aerospace Stealth Platforms

We present the design of a wheel-shaped resistive frequency selective surface (RFSS) based ultra-broadband radar absorber working for 5.2.-18.7 GHz. The proposed absorber has been designed using customized resistive material having a surface resistance value of $270 \Omega / \square$, employing aerograde glass fiber reinforced plastics (GFRP) laminate as a substrate material. The bottom layer has been terminated using a carbon - fibre reinforced plastics (CFRP) layer, which acts as a ground plane. The proposed RFSS absorber has been implemented and simulated with the help of CST microwave studio; the simulation result shows a minimum 10 dB reflection loss (RC) in the designated frequency, which covers C, X, and Ku bands. Typical absorption characteristics show fractional bandwidth (FBW) of 113%, with $0.044 \lambda \mathrm{L}$ (where $\lambda \mathrm{L}$ is the cutoff wavelength at 10 dB) thickness. The simulated design has been implemented for fabrication and validated experimentally, showing a close mutual agreement. The proposed absorber is thin (2.5mm) in nature, polarization insensitive (0° −90°), possesses good angular stability (0° −50°), and is easy to fabricate using a customized substrate, which makes it a potential candidate for aerospace stealth design.