A conformal coding metasurface for dual polarization conversion and radar cross section (RCS) reduction

Abstract

Integrated meta-devices are the need of modern stealth application systems and have recently received a great deal of attention. Most studies have concentrated on the physics and structural design of planar metasurfaces, while conformal design that is suitable for arbitrarily curved surfaces has been rarely discussed. In this study, a conformal polarization-independent 1-bit coding metasurface (CM) is proposed. A fundamental element of a proposed CM is firstly designed which converts the linearly polarized incident electromagnetic (EM) wave into its orthogonal equivalent at 8.53-11.63 and 18.67-22.34 GHz with a polarization-conversion-ratio (PCR) of more than 90%, and enables linear-to-circular polarization conversion from 12.40 to 17.56 GHz. Next, the basic element is rotated by 90° to generate another element with a phase difference of π between them. Both these elements are distributed in an array using a random aperiodic coding sequence to form 1-bit CM for RCS reduction. More than 10 dB RCS reduction for arbitrarily polarized waves has been realized in dual frequency bands ranging 8.75–11.22 and 19.10–21.20 GHz, for planar as well as with conformal structures. A prototype is fabricated, and the experiments show a good agreement with simulated results. Potential applications of the proposed design include reflector antennas, radar, satellite communication, and stealth technology.

Design, optimization, and comparative analysis of wide-band polarization conversion along with dual coding sequences for RCS reduction

“…With the introduction of the PB phase, an anisotropic structure can be rotated easily to achieve the phase difference. According to 39 the far-field scattering by coding metasurface can be expressed as Where and indicate the radiation intensity of each element and the array factor, respectively. k is the wavenumber vector and D is the size of the lattice.…”

“…The desired phase difference is achieved by rotating the anisotropic structure instead of employing multiple isotropic elements or adjusting specific size parameters, which is called the Pancharatnam-Berry (PB) phase. Several articles have utilized the aforementioned concept to minimize RCS 39 .In contrast to the existing literature, which often achieves limited or specific frequency bandwidth, and typically presents a single metasurface configuration, our proposed work introduces a novel approach by using wideband metasurface and demonstrate its effectiveness in reducing RCS using both chessboard and coding configurations.…”