Ultrathin lightweight flexible dual-polarized ultra-wideband electromagnetic wave absorbing composites based on complex pattern units

Abstract

Electromagnetic wave absorbing materials raise research interest because their application in electromagnetic radiation control and other energy conversion domains. In addition, expansion mechanism of absorption band width under fixed thickness becomes critical for engineering utilities. Here, an electromagnetic wave absorbing composite based on a complex pattern unit array film and honeycombs is proposed and experimentally validated. Based on the composite forming process, samples are obtained with small thickness, lightweight, flexible, and dual-polarized ultra-wideband absorbing traits. The reflection coefficient remains ≤−10 dB over 2–18 GHz, with an overall thickness of approximately 4 mm and an areal density of about 0.55 kg/m2. The underlying mechanism is analyzed by surface-current distribution in different frequency domains. Surface-current analyses reveal that the broadband absorption mechanism primarily relies on the double-layer cosine-function resistive patterns, which excite continuously distributed multiscale current loops and magnetic dipole resonances over the entire operating band. These resonances lead to a smooth variation of the effective impedance in the frequency domain and cause absorption dips at different frequencies to connect and complement one another in the spectrum, thereby achieving overall broadband, high-efficiency absorption. Bulging and bent-conformal tests are further conducted, and the results indicate that the designed ultra-wideband metasurface retains pronounced broadband absorption even under deformation, confirming its stability and robustness under complex conditions. This study provides a series of engineering favorable functions and their design method for vehicle outer envelopes and radiation control devices.