Multimode Miniature Polarization-Sensitive Metamaterial Absorber with Ultra-Wide Bandwidth in the K Band.

Metamaterial absorbers have gained widespread applications in fields such as sensing, imaging, and electromagnetic cloaking due to their unique absorption characteristics. This paper presents the design and fabrication of a novel K-band polarization-sensitive metamaterial absorber, which operates in the frequency range of 20.76 to 24.20 GHz for both TE and TM modes, achieving an absorption rate exceeding 90% and a bandwidth of up to 3.44 GHz. The structure of the metamaterial absorber consists of a rectangular aperture metallic patch, two metallic rings, and two metallic strips, with a metallic patch structure on the back. Both metallic patches are printed on a 1.575 mm-thick FR-4 substrate. In the TE mode, the performance shows diagonal symmetry, with a minimum absorption bandwidth of 1.4 GHz at 45° and a maximum of 3.44 GHz at 0°. The absorption rate exceeds 90% across various polarization angles. In terms of conventional modes, both the TE and TM modes can achieve ultra-wideband absorption. For specific scenarios requiring single-frequency or multi-frequency absorption, the desired functionality can be realized by varying the incident angle. These exceptional characteristics confer strong applicability for high-bandwidth electromagnetic wave absorption and specific frequency point absorption, indicating significant potential and practical value in the field of wireless communication.