A Low-Profile Water-Based Absorber for Large Angle Oblique Incidence

A polarization-insensitive and angle-insensitive metamaterial absorber containing metallic resonators printed on a dielectric substrate, a layer of pure water, and a metallic ground plane printed on a dielectric substrate is proposed in this work. The structure achieves a low-profile configuration with a thickness of only 0.048λ through the high permittivity of water, while the metallic frequency selective surface enables impedance matching under oblique incidence, thereby enhancing angular stability. The proposed absorber maintains over 90% absorptivity for incident angles ranging from 0° to 50° for TE-polarized waves and from 0° to 84° for TM-polarized waves. The proposed absorber can be effectively deployed in airport electromagnetic environments to mitigate electromagnetic interference (EMI) issues caused by multipath propagation and high-density signal sources.