High-Efficiency Dual-Frequency Reflective Linear Polarization Converter Based on Metasurface for Microwave Bands

Abstract

A dual-broadband and high-efficiency reflective linear polarization converter based on an anisotropic metasurface is presented. The device consists of two symmetrical, double-slotted metallic split-rings and one criss-cross structure, a dielectric layer, and a completely reflective metallic ground. The converter exhibits four resonances and can near-perfectly convert x- or y-polarized incident waves into cross-polarized waves in the frequency ranges of 9.38–13.36 GHz and 14.84–20.36 GHz. The polarization conversion ratios (PCRs) of the two bands are 98.21% and 99.32%, respectively. The energy conversion ratio (ECR) for energy loss measurement is almost 100% in these frequency bands. The polarization conversion principle is studied. The bandwidths and PCRs of the two bands are determined by varying the dielectric layer thickness. The simulation results are consistent with experimental observations. The designed dual-broadband and high-efficiency metasurface has great potential in the application of electromagnetic polarization control.

Toroidal Metaphotonics and Metadevices

“…[99,100] In that respect, researchers have extensively focused on inducing toroidal dipoles in an artificial media consisting of meticulously engineered planar metallic and dielectric unit cells (Figure 3). [56,61,[70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87]101,102] Easy and cost-effective fabrication steps, simple modeling and quick numerical computations, compatibility with other planar devices in photonic/plasmonic circuits, as well as reduced radiative losses have inspired researchers to develop artificial media based on flatland optics toward this purpose. In principle, in an aligned planar unit cell composed of multiple resonators, the formation of a spinning toroidal feature stems from the discrepancy between the direction of induced magnetic dipole moments in proximal resonators, known as magnetic dipole-induced toroidal dipole moment.…”

“…Apart from the above study, there is an ongoing race to enhance the performance of metaswitches using toroidal metasurfaces. [ 75,78,227 ] Specifically, at the telecommunication bandwidth, the toroidal metasurface concept has addressed some of the current limitations (e.g., MD, insertion loss) of traditional optical metaswitches. As discussed earlier in this section, optothermally tunable compounds (e.g., PCMs) have an undeniable role in improving the functionality of optical devices.…”

“…[32,33,[65][66][67][68][69][70][71][72][73] Owing to the ability of tightly squeezing electromagnetic fields and supporting ultrasharp resonance lineshapes, very recently, the practical use of toroidal metastructures has obtained considerable research attention. [57,69,74] Considering the unique advantages of these spectral features, well-engineered toroidal unit cells have emerged for designing strategic subwavelength devices, such as large modulation-depth modulators, [75][76][77][78][79][80] augmented nonlinear harmonic signal sources, [81] high-photon yield photodetectors, [82,83] and extremely sensitive and precise immunobiosensors. [84][85][86][87] This contribution aims to highlight and focus on the most recent and important devices enabled by toroidal metasurface technology.…”

Polarization Control with Helical Metasurfaces

“…We can see that with combination shown in Figure 3a, we can satisfy requirements (6) if φ co r = π. The perfect copolarized reflectance is desired for applications of polarizers, wavefront shaping in reflection, and anomalous reflection and usually achieved using metasurfaces based on omega-type inclusions, crossed H-shaped metallic pattern, double-slotted metallic split-rings, and others [54][55][56]. Most of these works use three-layer metasurfaces with the metallic plane, which leads to opacity out of the resonance band.…”

Ultra-Wideband and Lightweight Electromagnetic Polarization Converter Based on Multiresonant Metasurface

“…Therefore, the conventional designs are usually heavy-weight, difficult in miniaturization, and narrow bandwidth, which limits their practical applications [5], [6]. Since then, many efforts have been made to overcome the disadvantage of the conventional polarization converters [7]- [18]. Among the proposed methods, using metamaterials (MMs) is considered as a potential approach to developing a new class of miniaturized and wideband polarization converter [15]- [18].…”