Bi-functional Metasurface Polarizer for Reflected and Transmitted Waves

2021 ◽  
Author(s):  
Xiaojun Huang ◽  
Xia Ma ◽  
Xuewen Li ◽  
Jingdao Fan ◽  
Liang Guo ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Conversion Rate ◽  
Electromagnetic Waves ◽  
Oblique Incidence ◽  
Surface Current ◽  
Axial Ratio ◽  
Polarization Conversion ◽  
Polarized Waves ◽  
Transmitted Waves ◽  
Polarization Converters

Abstract Manipulating the polarizations of electromagnetic waves by flexible and diverse means is desirable for a myriad of microwave systems. More recently, metasurfaces offer the promising alternatives to conventional polarization manipulating components because of the flexibility of their geometry could be arbitrarily customized. In this context, a bi-layered metasurface was presented to simultaneously manipulate the polarized states of reflected and transmitted microwaves. No matter whether the incident electromagnetic wave is x-polarized or y-polarized, the reflected and transmitted waves will be converted into orthogonal y- polarized waves at the operating frequency. The designed metasurface has a high polarization conversion rate(PCR) above 90% for both normal and oblique incidence. The experimental results verify the correctness of the simulated results. Finally, axial ratio and surface current distributions were employed to reveal the physics of polarization manipulation. The proposed metasurface will be beneficial to the design of flexible and versatile polarization converters and has great potential for applications in polarization controlled devices and also is believed extendable to higher frequency regimes.

Fission Transmission Linear-to-Circular Polarization Conversion Based on Compact Bi-Layer structure

2016 ◽  
Vol 3 (3) ◽  
pp. 519 ◽  
Author(s):  
Farman Ali Mangi ◽  
Shaoqiu Xiao ◽  
Ghulam Ali Mallah ◽  
Ghulam Fatima Kakepoto ◽  
Imran Memon
Keyword(s):  
Circular Polarization ◽  
Electromagnetic Waves ◽  
Layer Structure ◽  
Normal Incidence ◽  
Dielectric Substrate ◽  
Polarization Conversion ◽  
Novel Approach ◽  
Polarized Waves ◽  
Transmitted Waves ◽  
Resonance Frequencies

<p>A fission transmission linear-to-circular polarization conversion based on bi-layer structure is proposed which is composed of 3 × 3 array to convert linear-to-circular polarized wave. The structure is constructed by half square with “H” shape printed on both sides of the dielectric substrate that are subjected to obtain multi-band at resonance frequencies. The proposed structure realizes the giant circular polarization under the normal incidence for right and left circular polarized waves. After transmission, the incident wave decomposed into two orthogonal linear components have equal magnitudes and 90o phase difference between them. The novel approach of “fission transmission of electromagnetic waves” is firstly introduced to understand the physics of giant circular polarization conversion which is based on the sequence of incident and transmitted waves to generate strong circular dichroism.</p>

Transmissive 2-bit anisotropic coding metasurface

2022 ◽  
Author(s):  
Pengtao Lai ◽  
Zenglin Li ◽  
Wei Wang ◽  
Jia Qu ◽  
Liang Wei Wu ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Electromagnetic Wave ◽  
Circular Polarization ◽  
Orbital Angular Momentum ◽  
Electromagnetic Waves ◽  
Beam Splitter ◽  
Far Field ◽  
Polarization Conversion ◽  
Field Patterns ◽  
Phase Profile

Abstract Coding metasurfaces have attracted tremendous interests due to unique capabilities of manipulating electromagnetic wave. However, archiving transmissive coding metasurface is still challenging. Here we propose a transmissive anisotropic coding metasurface that enables the independent control of two orthogonal polarizations. The polarization beam splitter and the OAM generator have been studied as typical applications of anisotropic 2-bit coding metasurface. The simulated far field patterns illustrate that the x and y polarized electromagnetic waves are deflected into two different directions, respectively. The anisotropic coding metasurface has been experimentally verified to realize an orbital angular momentum (OAM) beam with l = 2 of right-handed polarized wave, resulting from both contributions from linear-to-circular polarization conversion and the phase profile modulation. This work is beneficial to enrich the polarization manipulation field and develop transmissive coding metasurfaces.

Ultra-wideband Transmissive Linear Polarization Device Based on Graphene

2021 ◽  
Vol 36 (7) ◽  
pp. 914-921
Author(s):  
Liwei Guo ◽  
Simin Li ◽  
Xing Jiang ◽  
Xin Liao ◽  
Lin Peng
Keyword(s):  
Silicon Dioxide ◽  
Oblique Incidence ◽  
Chemical Potential ◽  
Ultra Wideband ◽  
Polarization Conversion ◽  
Well Performance ◽  
Transmitted Waves ◽  
Relative Bandwidth ◽  
Terahertz Applications ◽  
Transmission And Absorption

In order to achieve both adjustable wideband and high Polarization Conversion Rate (PCR) of the transmitted waves, a novelty tri-layered structure is proposed for terahertz applications. The Rhombus Hollow Square (RHS) is built up by top and bottom gold gratings on Silicon Dioxide and Polyamide substrate with graphene strips. The proposed polarizer broadens the bandwidth and has well performance. As chemical potential increases, the bandwidth is also broadened by adjusting the graphene. From 0.5 THz to 3 THz, the PCR is greater than 90%, and the relative bandwidth up to 142.9%. The transmission and absorption of polarizer are analyzed at the oblique incidence with chemical potential 0.1eV. By simulating and analyzing the performance, a new result of maintaining broadband and high transmittance in oblique incidence is obtained.

Linear to left- and right-hand circular polarization conversion by using a metasurface structure

2017 ◽  
Vol 10 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Oguzhan Akgol ◽  
Olcay Altintas ◽  
Emin Unal ◽  
Muharrem Karaaslan ◽  
Faruk Karadag
Keyword(s):  
Axial Ratio ◽  
Wide Band ◽  
Polarization Conversion ◽  
Band Frequency ◽  
Left Handed ◽  
Linear Waves ◽  
Polarized Waves ◽  
Unit Cells ◽  
Linearly Polarized ◽  
Parallel Strips

By using a metasurface (MS) structure, a linearly polarized wave is converted to circularly polarized waves. Both right- and left-handed circular polarizations (RHCPs and LHCP) are obtained by a simple configuration in the proposed structure which consists of 16 unit cells arranged in a 4 × 4 layout. Each unit cell contains five horizontal and parallel strips embedded in a rectangular frame in which a single diagonal strip is placed from one corner to the opposed one. It is shown that the orientation of the diagonal line determines the handedness of the converted signal to be either LHCP or RHCP. In order to show the working conditions of the MS structure, scattering parameters are found for both co-polarized and cross-polarized responses. Axial ratio, an indicator for polarization conversion, is then obtained by dividing cross-polar response to co-polar response to demonstrate the transformation. The structure works for horizontally and vertically polarized linear waves in a wide band frequency range which is approximately 510 MHz. Since the suggested MS model is composed of a simple geometry for polarization conversion, it can be easily adjusted in any desired frequency bands for a variety of applications from the defence industry to medical, education, or communication areas.

scholarly journals Reconfigurable Polarizer Based on Bulk Dirac Semimetal Metasurface

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 228
Author(s):  
Yannan Jiang ◽  
Jing Zhao ◽  
Jiao Wang
Keyword(s):  
Physical Mechanism ◽  
Axial Ratio ◽  
Polarization Conversion ◽  
Cross Polarization ◽  
Frequency Range ◽  
Dirac Semimetal ◽  
Polarized Waves ◽  
Orthogonal Components ◽  
The Cross ◽  
Conversion Efficiencies

In this paper, we propose a reflective polarizer in terahertz regime, which utilizes the Bulk-Dirac-Semimetal (BDS) metasurface can be dynamically tuned in broadband. The proposed polarizer is capable of converting the linear polarized wave into the circular polarized or the cross polarized waves by adjusting the Fermi energy (EF) of the BDS. In the frequency range of 0.51 THz and 1.06 THz, the incident linear polarized wave is converted into a circular polarized wave with an axial ratio (AR) less than 3 dB when EF = 30 meV. When EF = 45 meV, the cross-polarization conversion is achieved with the polarization conversion ratio (PCR) greater than 90% in the band of 0.57−1.12 THz. Meanwhile, the conversion efficiencies for both polarization conversions are in excess of 90%. Finally, the physical mechanism is revealed by the decomposition of two orthogonal components and the verification is presented by the interference theory.

scholarly journals Numerical Evaluation of Electromagnetic-wave Penetration at Normal Incidence through an Inhomogeneous-wave Approach

2018 ◽  
Vol 2 ◽  
pp. 76-86
Author(s):  
Alessandro Calcaterra ◽  
Fabrizio Frezza ◽  
Patrizio Simeoni ◽  
Nicola Tedeschi
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Numerical Evaluation ◽  
Oblique Incidence ◽  
Normal Incidence ◽  
Deep Penetration ◽  
Inhomogeneous Wave ◽  
Separation Surface ◽  
Lossy Medium ◽  
The One

This paper presents numerical scenarios concerning penetration in a lossy medium that can be obtained by radiating inhomogeneous electromagnetic waves. Former papers approached this problem, both analytically and numerically, finding requirements and limits of the so-called “deeppenetration” condition, which consists of a wave transmitted in a lossy medium having an attenuation vector whose direction forms the angle of ninety degrees with the normal to the separation surface. The deep-penetration condition always requires an oblique incidence, therefore is not practical in many applications. For this reason, we are interested here in finding whether an inhomogeneous wave guarantees larger penetration than the one obtainable with homogeneous waves, even when the incident wave is normal to the separation surface between two media, i.e. when the deep-penetration condition is not satisfied. We are also interested in verifying numerically whether the lossy-prism structure may achieve larger penetration than the one obtainable through traditional leakywave antennas, and we also wish to propose a lossy-prism design more realistic than the one previously presented in the literature.

New Crack Detection Method by Using Electromagnetic Wave

2004 ◽  
Author(s):  
Hidetoshi Hashizume ◽  
Takuya Shibata ◽  
Kazuhisa Yuki ◽  
Takahiro Yoshioka
Keyword(s):  
Electromagnetic Wave ◽  
Surface Crack ◽  
Electromagnetic Waves ◽  
Crack Detection ◽  
Detection Method ◽  
Plasma Discharge ◽  
Experimental Results ◽  
Transmitted Waves ◽  
Inner Surface

The NDT method using electromagnetic waves has the possibility to detect widely and quickly inner surface crack existing in large pipes. The purpose of this study is then to demonstrate validity of the method to detect the thin crack introduced by plasma discharge fabrication. Through this study, it has been shown that both reflected and transmitted waves carry a lot of information on existence of the crack. Experimental results indicate that there exists attractive possibility in this new NDT method.

Design of Transmission Polarization Metasurface Converter

2021 ◽  
Vol 1035 ◽  
pp. 718-723
Author(s):  
Bo Wen Han ◽  
Si Jia Li ◽  
Xiang Yu Cao ◽  
Jun Gao
Keyword(s):  
Simple Structure ◽  
Axial Ratio ◽  
Polarization Conversion ◽  
Current Analysis ◽  
Polarization Converter ◽  
Circularly Polarized ◽  
Polarized Waves ◽  
Relative Bandwidth ◽  
Linearly Polarized ◽  
Simulation Results

The transmission polarization metasurface converter is an effective method to realize the polarization manipulation of the transmission waves, and it is also the research hotspot of metasurfaces. A new broadband transmissive polarization converter was proposed based on the metasurfaces converted incident linearly polarized waves into circularly polarized waves of transmission. The top and bottom layers of the unit were axisymmetric metal patches. The top and bottom layers of metal patches were overlapped and the shape was like an arrow. The thickness of the substrate was 4mm. The polarization conversion mechanism of metasurface was illustrated by parameter optimization and current analysis. The simulation results show that when the metasurface works in the frequency band of 6.71GHz~8.45GHz, the linearly polarized incident wave can be converted into a circularly polarized transmitted wave with axial ratio less than 3dB, and the relative bandwidth can reach 23%. The designed polarization converter has a simple structure and the potential application value in electromagnetic wave control of radio frequency devices.

scholarly journals Terahertz Broadband Polarization Conversion for Transmitted Waves Based on Graphene Plasmon Resonances

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 56
Author(s):  
Anqi Yu ◽  
Dahai Yu ◽  
Zhenyu Yang ◽  
Xuguang Guo ◽  
Yuxiang Ren ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Destructive Interference ◽  
Polarization Conversion ◽  
Plasmon Excitation ◽  
Integer Multiple ◽  
Metallic Grating ◽  
Scattering Rate ◽  
Transmitted Waves ◽  
Metallic Gratings ◽  
Plasmon Resonances

We applied the harmonic oscillator model combined with the transfer matrix method to study the polarization conversion for transmitted waves in metallic grating/plasmon-excitation layer/metallic grating structure in the terahertz (THz) region. By comparing the calculated spectra and the simulated (by the finite-difference-time-domain method) ones, we found that they correspond well with each other. Both methods show that the Drude background absorption and the excited plasmon resonances are responsible for polarization conversion. The transmission is close to 0 when the distance between the top/bottom metallic gratings and gated graphene is an integer multiple of half the wavelength of the incident wave (in the dielectrics), at which points the plasmon resonances are greatly suppressed by the destructive interference between the backward/forward electromagnetic waves and that reflected by the top/bottom metallic gratings. Away from these points, the transmission can be higher than 80%. The electron density and the excitation efficiency of the plasmon-excitation layer were found to be important for the bandwidth of the polarization conversion window, while the scattering rate was found to influence mainly the polarization conversion rate. Multi-broadband polarization conversion is realized by exciting plasmon modes between the 0 transmission points in the THz region.

Detection of delamination in composites by using electromagnetic penetrating radar

2014 ◽  
Vol 5 (2) ◽  
pp. 151-156
Author(s):  
Z. Mechbal ◽  
A. Khamlichi
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Wave Reflection ◽  
Image Features ◽  
Partial Reflection ◽  
Straight Path ◽  
Reflected Signal ◽  
Short Time ◽  
Intervening Factors

Composites made from E-glass/epoxy or aramid/epoxy are frequently used in aircraft and aerospace industries. These materials are prone to suffer from the presence of delamination, which can reduce severely the performance of aircrafts and even threaten their safety. Since electric conductivity of these composites is rather small, they can propagate electromagnetic waves. Detection of delamination damage can then be monitored by using an electromagnetic penetrating radar scanner, which consists of emitting waves having the form of short time pulses that are centered on a given work frequency. While propagating, these waves undergo partial reflection when running into an obstacle or a material discontinuity. Habitually, the radar is moved at constant speed along a straight path and the reflected signal is processed as a radargram that gives the reflected energy as function of the two-way time and the antenna position.In this work, modeling of electromagnetic wave propagation in composites made from E-glass/epoxy was performed analytically. The electromagnetic wave reflection from a delamination defect was analyzed as function of key intervening factors which include the defect extent and depth, as well as the work frequency. Various simulations were performed and the obtained results have enabled to correlate the reflection pattern image features to the actual delamination defect characteristics which can provide quantification of delamination.

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