In this paper, an optically transparent metamaterial with broadband absorption is presented theoretically and demonstrated experimentally. The design comprises of structures made of resistive films of indium-tin-oxide and the metamaterial exhibits over 10 dB absorption in the frequency range of 6.06–14.66 GHz. The novelty of the structure lies in its large absorption bandwidth along with a reduced thickness and optical transparency compared to broadband absorbers reported earlier. Besides, the proposed design is polarization-insensitive and gives rise to angular independent absorption for both transverse electric and transverse magnetic polarizations. The absorption mechanism in the structure has been studied by deriving an equivalent circuit model as well as analyzing several design parameters. Finally, a prototype of the proposed structure has been fabricated and measured, which shows good agreement with the simulated results.

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In this letter, a polarization‐insensitive broadband rasorber structure with in‐band transmission response has been presented. The proposed structure comprises a periodic arrangement of convoluted cross‐dipole pattern in the top layer and square slot geometry in the bottom layer. Lumped resistors are symmetrically mounted across the top pattern to result in wideband absorption, whereas in‐band transmission is obtained by careful design of the square slot in the bottom layer. The overall structure exhibits a broad absorption band (having reflection coefficient below −10 dB) in the range of 2.18 to 9.80 GHz, and the transmission band appears at 6 GHz with an insertion loss of 0.56 dB. The novelty of the proposed design lies in its compact topology, polarization‐insensitivity, angular stability, and in‐band transmission response unlike the existing rasorber structures. Surface current distribution, equivalent circuit model, and several parametric variations have also been illustrated for in‐depth analysis. A sample prototype has been fabricated and the measured results show a good agreement with the simulated responses, under normal as well as oblique incidence.