4-Bit Optimized Coding Metasurface for Wideband RCS Reduction

Abstract

In this paper, a 4-bit reflective coding metasurface with the polarization-insensitive unit cell is designed for wideband radar cross section (RCS) reduction. The metasurface unit has rotational symmetry; therefore, it produces the same electromagnetic scattering response for both x-and y-polarizations. To attain 4-bit phase response, the dimensions of the unit cell are optimized so that a phase difference of 22.5 • is realized between respective digital elements and the magnitude of reflection is more than 0.95 from 15 GHz to 40 GHz. Therefore, 16 digital elements have phases of θ, θ + 22.

Passive techniques for target radar cross section reduction: A comprehensive review

“…This arrangement was optimized and the RCSR bandwidth of the novel diffusion metasurface (5.4‐7.4 GHz) was expanded by 67% compared with the conventional arrangement (6‐6.85 GHz and 7.25‐7.6 GHz). In Reference 145, a coding metasurface with the polarization‐insensitive unit cell was designed which achieved more than 10‐dB RCSR in a wide frequency band from 15 to 40 GHz (91%) except for 17 to 18 GHz where RCSR is more than 7.8 dB. Haji‐Ahmadi et al 120 designed a pixelated checkerboard metasurface by two unit cells (square patches) on a double‐layer substrate based on the pixilation and optimization of a square patch for ultra‐wideband 10‐dB RCSR of 95%.…”

“…In Table 2, the thinnest substrate thicknesses belong to References 84, 91, 94 with the values of 3, 3.3, and 3 mm, respectively. In Table 3, the thinnest substrate thicknesses belong to References 105, 106, 145 with the values of 1.5, 1.5748, and 1.5 mm, respectively.…”

“…The last columns of all Tables 1‐3 refer to the cons and pros of each work in each group of the techniques, which can be useful in evaluating the approaches and give a good view to us for future researches. According to these cons and pros, approaches of References 54, 57, 61, 72–74, 77 in Table 1, References 80, 88, 91–95 in Table 2, and References 108–110, 113, 128, 143, 145 in Table 3, have some significant particular properties.…”

“…Additionally, most of them have been performed only for monostatic RCSR at normal incident angle ignoring the wave polarization. Hence, nowadays, the modern passive techniques and structures based on phase cancelation or destructive interference using surfaces including frequency selective surface (FSS), 52‐55 EM band gap (EBG), 56‐59 artificial magnetic conductor (AMC), 47,48,60‐77 polarization rotation reflective surface (PRRS), 78‐95 metasurfaces, 96‐145 and hybrid methods, 146‐149 receive a lot of attention to improve the mentioned conventional techniques and overcome their limitations. In the recent decades, researchers have made a lot of efforts on these modern passive RCSR techniques and numerous works have been proposed and completed in order to achieve a system similar to the ideal RCSR system.…”

Construction of a Cost-Effective Phased Array Through High-Efficiency Transmissive Programable Metasurface

“…Within microwave domain, metasurfaces also arouse a wide range of investigation, such as radiation improvement [5][6][7], perfect absorbers [8,9], OAM-EM wave generation [10][11][12][13], scattering reduction [14][15][16], holographic imaging [17,18], and energy harvesting [19]. Metasurfaces particularly demonstrate the unique abilities in waveform shaping through the phase manipulation of the building units in microwave metasurfaces.…”