An Ultra-Wideband Reflective Linear-to-Circular Polarization Converter Based on Anisotropic Metasurface

Abstract

In this work, an ultra-wideband and high-efficiency reflective linear-to-circular polarization converter based on an anisotropic metasurface is proposed, which is an orthotropic structure with a pair of mutually perpendicular symmetric axes u and v along ±45 • directions with respect to the vertical y axis. The simulated and experimental results show that the polarization converter can realize ultrawideband linear-to-circular polarization conversion at both x-and y-polarized incidences, its 3dB-axialratio-band is between 5.8 and 20.4 GHz, which is corresponding to a relative bandwidth of 112%; moreover, the polarization conversion efficiency (PCE) can be kept larger than 99.6% in the frequency range of 6.1-19.8GHz. In addition, to get an insight into the root cause of the LTC polarization conversion, a detailed theoretical analysis is presented, in which the conclusion is reached that in the case of neglecting thelittle dielectric loss, the axial ratio (AR) of the reflected wave can be completely determined by the phase difference between the two reflection coefficients at u-and v-polarized incidences, and any anisotropic metasurface can be used as an effective LTC polarization converter when the phase difference is close to ±90 • .

Broadband linear‐to‐circular polarization reflector using anisotropic metasurface

“…In general, the quantification of circular polarization property adopts 3-dB axial ratio (AR) relative bandwidths. 30 The value of AR can be calculated by…”

“…It implies that the linearly polarized normal incident wave is converted into the circularly‐polarized wave and the reflected wave is a RHCP one propagating along + z direction in the operating frequency range. In general, the quantification of circular polarization property adopts 3‐dB axial ratio (AR) relative bandwidths 30 . The value of AR can be calculated by wherein a = |R yy | 4 + |R xy | 4 + 2|R yy | 2 |R xy | 2 cos(2Δ φ yx ).…”

“…[22][23][24] In this work, we pay more attention to various metasurfaces that have been proposed to generate the circularly polarized (CP) wave. In previous literature, there have been many kinds of metasurfaces applied to the CP generation, such as anisotropic frequency-selective surfaces, 25 polarization dependent electromagnetic band gap, 10,26 multilayer graphene sheets, 27 microsplit Jerusalem-cross metasurface, 28 complementary structure, 29 double-layer structure, 30 resonator structure, 31,32 dipole array and meander lines. 33,34 In short, for the design of linear-to-circular polarization converters (LCPC), the bandwidth as well as thickness have proved to be key indicators.…”

An Ultra-Wideband Circular Polarization-Maintaining Metasurface and Its Application in RCS Reduction

“…Over the past decade, it has been found that metasurface can provide a convenient way to control the polarization state of EM wave. In recent years, to update the conventional design method, many different types of polarization converters have been proposed based on various anisotropic or chiral metasurfaces, which can perform different polarization conversions, such as cross polarization conversion [3][4][5][6][7][8][9][10] or linear-to-circular polarization conversion [11][12][13][14][15][16][17] . In addition, A righthanded/left-handed circularly polarized (RCP/ LCP) wave will be converted to a LCP/ RCP one after reflection on a conducting surface, however, based on a proper anisotropic or chiral metasurface, a CP-maintaining metasurface can be proposed, which can keep the handedness of the reflected wave the same as that of the CP incident one.…”

A Broad-Band Wide-Angle Linear-to-Circular Polarization Converter Based on Stripline Metasurface

“…This requires a converter that can convert linearly polarized electromagnetic waves into circularly polarized electromagnetic waves. According to transmission type, electromagnetic wave polarization converters are divided into two types: reflective converters [1][2][3] and transmissive converters . Compared with a reflective converter, a transmissive converter can be better integrated into the system because it can be very close to the radiator device, providing a more compact system.…”