volume | PIER Journals

Abstract

A novel wideband cross-polarized coding metasurface has been presented in this paper towards reduction of monostatic radar cross section (RCS). A broadband reflective cross-polarization converter for linearly polarized (LP) electromagnetic waves covering both X and Ku bands has been designed for this purpose. The proposed unit cell is ultrathin (λ/15.7) and demonstrates a polarization conversion bandwidth of 10.84 GHz from 7.96 GHz to 18.8 GHz for a linearly polarized normal incidence wave which helps in reduction of radar cross section. In order to have a better understanding of cross polarization conversion (CPC), the physical mechanism of the structure has been investigated and elucidated in detail, along with the surface current distribution. The proposed structure has been studied for both transverse electric (TE) and transverse magnetic (TM) polarizations. For 1 bit coding, the suggested unit cell is utilized as the `0' bit, while the 90˚ rotated version of the unit cell is used as the `1' bit. A 4 × 4 matrix is built, and 16 configurations are explored. These combinations are known as the 2 × 2 metasurface sub-blocks, and they are used to build 200 × 200 components with size of 180 mm × 180 mm. The RCS simulation studies have been carried out from 2 to 30 GHz, and the proposed design shows a 10 dB RCS reduction from 10 GHz to 20 GHz. The scattering pattern of the suggested metasurface is comprehensively analyzed at 10 GHz, 15 GHz, and 18 GHz and demonstrates diffuse scattering in the other direction, minimizing the forward scattering RCS. The designed structure of 2.4 mm thickness has been fabricated and measured in the X and Ku bands. The measured results are in good agreement with simulated ones. In order to show the efficiency of the proposed coding metasurface, monostatic RCS estimation of the wing and body sections of high altitude aerospace paltforms (HAPS) has been simulated, and a 14.32 dB reduction has been observed over the body cross section.

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Dr. E. V. Bhavya

Dr. Balamati Choudhury

Dr. Raveendranath Nair