Wide-angle, polarization-insensitive dual-band metamaterial absorber for electromagnetic interference shielding application

We present a dual-band metamaterial absorber (MMA) architecture designed for high-performance microwave shielding and sensing applications. The unit cell features a symmetric crossed petal resonator structure built on a Rogers RT5880 substrate with an electrical dimensions of 0.12λ×0.12λ×0.005λ, where λ corresponds to 0.9 GHz. The proposed MMA achieves near-perfect absorption rates of 99.4% and 99.92% at 0.9 and 1.8 GHz, respectively. Electromagnetic (EM) parameter retrieval confirms double-negative behavior at both resonances, with simultaneous negative real parts of permittivity and permeability. The absorber is polarization-insensitive up to 60 deg and maintains stable performance across varying incident angles. Equivalent circuit modeling using ADS Design System validates the CST Studio Suite simulation results, ensuring accuracy of reflection characteristics. The absorption mechanism is further explored through surface current and EM field distributions. A prototype is fabricated and experimentally tested, with measured results showing strong agreement with simulations. Shielding effectiveness values of 50.8 and 70.3 dB were recorded at the two absorption peaks. In addition to absorption performance, the MMA demonstrates effective material sensing capabilities, exhibiting detectable frequency shifts when tested with materials such as FR-4, RO4003, RO4350, and RT5880. Quality factors of 22.4 and 26 further highlight its resonance sharpness. With its compact design, excellent angular stability, and strong dual-band performance, the proposed MMA holds significant potential for integration into EM shielding systems for global system for mobile communications (GSM) 900/1800 MHz and precision material sensing platforms.