Abstract
This work introduces a dual‐polarized metamaterial absorber with a wide transmission window located between two absorption bands. The structure is designed to achieve strong out‐of‐band absorption while maintaining broad in‐band transmission. The top resonator includes four modified split‐ring resonators with lumped resistors to achieve broad out‐of‐band absorption on both sides of the transmission window. The lower layer consists of a rectangular slot that operates as a parallel LC resonator, forming a band‐pass frequency‐selective surface (FSS) that provides a broad in‐band transmission window while simultaneously serving as a defected ground plane to enhance out‐of‐band absorption. With an overall thickness of 0.075
λ
L
, the proposed design achieves a 120% fractional bandwidth and maintains absorptivity greater than 80% over the 2.5–10.0 GHz frequency range, while exhibiting a low insertion loss of 1.0 dB at the center frequency of 5.98 GHz. The proposed rasorber demonstrates excellent overall performance by combining a wide out‐of‐band absorption, a broad in‐band transmission, a high fractional bandwidth, low electrical thickness, angular stability, dual‐polarization characteristics, and a simple, cost‐effective fabrication approach. Equivalent circuit modeling, parametric analysis, polarization analysis, and surface current distribution studies are performed to investigate the operating mechanism and validate the performance of the proposed rasorber. The measured results of the fabricated prototype are in close agreement with the simulated results. The proposed rasorber exhibits significant potential for deployment in radomes, high‐data‐rate multiband communication systems, and other RCS‐sensitive platforms.