A thin, broadband frequency-selective surface (FSS)-based multilayer microwave absorber is proposed for stealth applications. The design integrates two material layers composed of e-waste-derived copper composite and ball-milled cobalt, strategically incorporated above an FSS-patterned FR-4 substrate. The FSS geometries, featuring simple square loops and cross dipoles, are optimized to achieve enhanced absorption performance while maintaining structural simplicity. The material layers are developed using ball milling (5 h) for cobalt and a blending method for the e-waste/copper composite, and their experimentally measured complex permittivity and permeability are used as inputs for full-wave electromagnetic simulations. The simulated reflection loss results demonstrate a broadband operating frequency range of 7.46 to 18 GHz with reflectivity below −10 dB, achieved with a compact total thickness of 2.3 mm. This design establishes a cost-effective and high-performance solution for advanced microwave absorption applications.
Verma et al. (Thu,) studied this question.