Hybrid ECM Blended Whale Optimization Derived Frequency-Selective Conformal EMI Shielding Structure Using Ferrite Substrate

In this work, both planar and conformal novel electromagnetic interference (EMI) shielding structures with customized properties are developed using a unique coupling of frequency-selective surface (FSS) and magnetic substrate. A hybrid equivalent circuit model (ECM) blended whale optimization (WO) technique is offered in the quest of customized shielding of L-, S-, C-, X-, and Ku-bands using a simple FSS geometry. The proposed structure is designed to shield L-, S-, C-, X-, and Ku-bands with a fractional bandwidth of 66.67%, 66.67%, 66.67%, 50.2%, and 40.50%, respectively. The frequency-dependent complex dielectric permittivity ( ε'- jε") and complex magnetic permeability ( μ'- jμ") of ferrite are measured using a waveguide measurement setup at X-band. The measured electromagnetic parameters are utilized in the modeling of planar and conformal ferrite-based frequency-selective shielding structures. An optimal ferrite coupled FSS shielding structure is fabricated, and its performance is evaluated using a non-destructive free-space microwave measurement setup. The measured results are found in congruence with the full-wave simulation and WO results. Besides, the conformal configuration of the proposed shielding structure is peculiarly investigated for inward and outward curved shielding structures for different values of radius of curvature. The proposed technique is intended to achieve a customized, simple, wideband, polarization-insensitive, and angular stable structure in the desired frequency regime, thus verifying the potential of the aforementioned technique for shielding applications.