scholarly journals Design of broadband metamaterial-based ferromagnetic absorber

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Yan Shi 1 ◽  
Jie Yang 1 ◽  
Hua Shen 1 ◽  
Zhankui Meng 1 ◽  
Tong Hao 1
Keyword(s):  
Incident Angle ◽  
Single Layer ◽  
Resonant Absorption ◽  
Periodic Array ◽  
Ferromagnetic Property ◽  
Microwave Frequencies ◽  
Absorption Bandwidth ◽  
Symmetric Structure ◽  
Polarization Insensitive ◽  
Absorption Mode

In this paper, a metamaterial-based ferromagnetic absorber has been designed at microwave frequencies. The proposed absorber is composed of a periodic array of stacked circular ferromagnetic patches fabricated on the FR4 substrate. With the ferromagnetic property, the single-layer patch array generates a good resonant absorption mode. By stacking multiple ferromagnetic patches, the designed absorber with the absorption above 90% has a wide absorption bandwidth from 10 to 21 GHz. Due to the symmetric structure, the proposed absorber is polarization insensitive. At oblique incident with the incident angle of 45o, the good absorption more than 80% can be achieved in the whole operation band.

scholarly journals Polarization-Insensitive Broadband THz Absorber Based on Circular Graphene Patches

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2709
Author(s):  
Jiajia Qian ◽  
Jun Zhou ◽  
Zheng Zhu ◽  
Zhenzhen Ge ◽  
Shuting Wu ◽  
...  
Keyword(s):  
Incident Angle ◽  
Structural Parameters ◽  
Single Layer Graphene ◽  
Localized Surface Plasmon ◽  
Wide Angle ◽  
Absorption Bandwidth ◽  
Broadband Absorption ◽  
Simulation And Optimization ◽  
Symmetrical Configuration ◽  
Polarization Insensitive

A polarization-insensitive broadband terahertz absorber based on single-layer graphene metasurface has been designed and simulated, in which the graphene metasurface is composed of isolated circular patches. After simulation and optimization, the absorption bandwidth of this absorber with more than 90% absorptance is up to 2 THz. The simulation results demonstrate that the broadband absorption can be achieved by combining the localized surface plasmon (LSP) resonances on the graphene patches and the resonances caused by the coupling between them. The absorption bandwidth can be changed by changing the chemical potential of graphene and the structural parameters. Due to the symmetrical configuration, the proposed absorber is completely insensitive to polarization and have the characteristics of wide angle oblique incidence that they can achieve broadband absorption with 70% absorptance in the range of incident angle from 0° to 50° for both TE and TM polarized waves. The flexible and simple design, polarization insensitive, wide-angle incident, broadband and high absorption properties make it possible for our proposed absorber to have promising applications in terahertz detection, imaging and cloaking objects.

An ultra-wideband, polarization insensitive metamaterial absorber based on multiple resistive film layers with wide-incident-angle stability

2020 ◽  
pp. 1-9
Author(s):  
Guangsheng Deng ◽  
Kun Lv ◽  
Hanxiao Sun ◽  
Yuan Hong ◽  
Xiaoying Zhang ◽  
...  
Keyword(s):  
Incident Angle ◽  
Metamaterial Absorber ◽  
Parameter Analysis ◽  
Ultra Wideband ◽  
High Symmetry ◽  
Large Wave ◽  
Absorption Frequency ◽  
Resistive Film ◽  
Absorption Bandwidth ◽  
Polarization Insensitive

Abstract In this work, we propose a broadband, polarization-insensitive and wide incident angle stable metamaterial absorber (MA) based on the resistive film. The absorber consists of a three-layer structure with each layer of dielectric substrate printed with different shapes of resistive film. The multilayer structure not only extends the absorption bandwidth but also maintains high absorption under large wave incident angles. Numerical simulation shows that the absorptivity of a normal incident wave is above 90% in the frequency range 2.34–18.95 GHz, corresponding to a relative absorption bandwidth of 156%. Moreover, the whole MA structure has a total thickness of 11.3 mm, corresponding to 0.09 λ0 at its lowest absorption frequency. Due to the high symmetry of the structure, the absorber has good polarization insensitivity. In addition, for both transverse electric and transverse magnetic incidence, the proposed absorber achieves an absorptivity of more than 80% at incident angles of up to 45° and thus has good stability for wide incident angles. The absorption principle of the absorber is analyzed by the surface current and power loss density distribution. Parameter analysis is also performed for bandwidth optimization. Due to its advantages of wideband absorption with high efficiency, the proposed absorber has the potential to be applied to the energy-harvesting and electromagnetic stealth fields.

Angle and polarization-independent miniaturized UWB FSS design

2021 ◽  
pp. 1-9
Author(s):  
Yanning Yuan ◽  
Yuchen Zhao ◽  
Xiaoli Xi
Keyword(s):  
Design Method ◽  
Incident Angle ◽  
Stop Band ◽  
Single Layer ◽  
Wireless Systems ◽  
Frequency Selective Surface ◽  
Ultra Wideband ◽  
Band Frequency ◽  
Gain Enhancement ◽  
Polarization Independent

Abstract A single-layer ultra-wideband (UWB) stop-band frequency selective surface (FSS) has several advantages in wireless systems, including a simple design, low debugging complexity, and an appropriate thickness. This study proposes a miniaturized UWB stop-band FSS design. The proposed FSS structure consists of a square-loop and metalized vias that are arranged on a single layer substrate; it has an excellent angle and polarization-independent characteristics. At an incident angle of 60°, the polarization response frequencies of the transverse electric and magnetic modes only shifted by 0.003 f0 and 0.007 f0, respectively. The equivalent circuit models of the square-loop and metallized vias structure are analysed and the accuracy of the calculation is evaluated by comparing the electromagnetic simulation. The 20 × 20 array constitutes an FSS reflector with a unit size of 4.2 mm × 4.2 mm (less than one-twentieth of the wavelength of 3 GHz), which realizes an UWB quasi-constant gain enhancement (in-band flatness is <0.5 dB). Finally, the simulation results were verified through sample processing and measurement; consistent results were obtained. The FSS miniaturization design method proposed in this study could be applied to the design of passband FSS (complementary structure), antennas and filters, among other applications.

scholarly journals Electrically Tunable Broadband Terahertz Absorption with Hybrid-Patterned Graphene Metasurfaces

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 562 ◽  
Author(s):  
Longfang Ye ◽  
Xin Chen ◽  
Guoxiong Cai ◽  
Jinfeng Zhu ◽  
Na Liu ◽  
...  
Keyword(s):  
Incident Angle ◽  
Single Layer ◽  
Normal Incidence ◽  
Transverse Magnetic ◽  
Single Layer Graphene ◽  
Terahertz Waves ◽  
Broadband Absorption ◽  
Terahertz Sensing ◽  
Axisymmetric Configuration ◽  
Broadband Terahertz

We numerically demonstrate a broadband terahertz (THz) absorber that is based on a hybrid-patterned graphene metasurface with excellent properties of polarization insensitivity, wide-angle, and active tunability. Our design is made up of a single-layer graphene with periodically arranged hybrid square/disk/loop patterns on a multilayer structure. We find that broadband absorption with 90% terahertz absorbance and the fractional bandwidth of 84.5% from 1.38 THz to 3.4 THz can be achieved. Because of the axisymmetric configuration, the absorber demonstrates absolute polarization independence for both transverse electric (TE) and transverse magnetic (TM) polarized terahertz waves under normal incidence. We also show that a bandwidth of 60% absorbance still remains 2.7 THz, ranging from 1.3 THz to 4 THz, for a wide incident angle ranging from 0° to 60°. Finally, we find that by changing the graphene Fermi energy from 0.7 eV to 0 eV, the absorbance of the absorbers can be easily tuned from more than 90% to lower than 20%. The proposed absorber may have promising applications in terahertz sensing, detecting, imaging, and cloaking.

scholarly journals Combined Mie Resonance Metasurface for Wideband Terahertz Absorber

2018 ◽  
Vol 8 (9) ◽  
pp. 1679
Author(s):  
Jie Hu ◽  
Tingting Lang ◽  
Changyu Shen ◽  
Liyang Shao
Keyword(s):  
Electric Fields ◽  
Incident Angle ◽  
Absorption Frequency ◽  
Variable Parameters ◽  
Absorption Bandwidth ◽  
Terahertz Absorber ◽  
Mie Resonance ◽  
Traditional Design ◽  
Single Block ◽  
Application Fields

In this paper, we propose a combined metasurface consisting of an aluminum substrate and an array of TiO2 blocks to achieve a wideband terahertz absorber. We incorporated several similar dielectric blocks with different side length into each unit cell. Each dielectric block could cause magnetic-resonance-inducing absorption effect with different peak wavelengths. Thus, our combined metasurface could achieve wider absorption frequency band than the traditional design when these dielectric blocks were properly designed. The absorption bandwidth could be widened nearly 2.5 times and 5 times compared to a single block case when there were four and nine blocks, respectively, andcouldbe further improved by increasing the number of combinations in structures (variable parameters included number, spacing, dimensions etc.). For both TE00 (the electric fields of the light polarized along the y-axis) and TM00 (the electric fields of the light polarized along the x-axis) polarization states, the absorption bandwidth could be widened effectively; even when the incident angle was 45°, the absorption rate could still reach about 75%. This structure is simple and easy to fabricate, and this design concept can also be used in various other application fields.

Compact, flexible and highly selective wideband complementary FSS with high angular stability

2021 ◽  
pp. 1-17
Author(s):  
Srimita Coomar ◽  
Santanu Mondal ◽  
Rajarshi Sanyal
Keyword(s):  
Dielectric Material ◽  
Incident Angle ◽  
Single Layer ◽  
Angular Stability ◽  
Band Edge ◽  
Transmission Line Model ◽  
Layer Structures ◽  
Sharp Band ◽  
Lc Circuit ◽  
Very High

Abstract This article presents a novel miniaturized (0.105λ0 × 0.105λ0) flexible complementary frequency selective surfaces (CFSS) structure with sharp band edge selectivity and very high angular stability. To explore two diverse applications as a passband and stopband filter, a novel complementary convoluted square loop (CCSL) type structure has been designed and investigated on ultrathin dielectric material of thickness 0.0023λ0. The second-order wide controllable passband with fractional bandwidth of 19.23% (−3 dB) and remarkably wide stopband of 64.7% (−10 dB) and 54.8% (−20 dB) respectively have been achieved by using a cascaded resonating structure which is composed of asymmetrical meandered CCSL array, arranged on two ultrathin dielectric layers with air foam separation. This particular format would lead to sharp band edge selectivity with steep roll-off (72.43 dB/GHz) and an excellent passband selectivity factor (0.731). An equivalent lumped LC circuit in conjunction with the transmission line model has also been adopted to comprehend the physical mechanism of the proposed single layer and double layer structures. Further, better passband and stopband angular stability at an oblique incident angle of 45° and the bending characteristics have also been investigated thoroughly for the proposed flexible CFSS to check their employability in different conformal structures with WiMAX passband and WLAN stopband application.

A Multiple-Bands Metamaterial Absorber Based in X, Ku and K-Band

2021 ◽  
Author(s):  
Muhammad Fahim Zafar ◽  
Usman Masud
Keyword(s):  
Single Layer ◽  
Wide Band ◽  
Metamaterial Absorber ◽  
Basic Unit ◽  
Frequency Range ◽  
Structure Form ◽  
Perfect Absorption ◽  
Polarization Insensitive ◽  
Band Absorption ◽  
K Band

Abstract Developing a highly efficient and multiple-bands metamaterial absorber is a hot issue in recent era. In this paper, A multiple-bands metamaterial absorber has been presented which is based in X, Ku and K-band. Firstly, we have designed two single layer basic unit cell of X-shape and cross-shape, then they are arranged in the multi-layers structure form for the purpose of obtaining multiple- bands and wide band absorption. The proposed absorber is able to work in multiple bands because it has six peaks in the frequency range of 8–24 GHz with having near perfect absorption. Moreover, the sixth peak has a wideband absorption which is 2.93 GHz. Furthermore, the proposed absorber is also tested for polarization insensitivity and also for oblique incidence. Absorption was found polarization insensitive with almost perfect absorption.

Polarization-Insensitive Dielectric Metamaterials Absorber for Near-Unity UV-Light Trapping in Monolayer Graphene

2020 ◽  
Author(s):  
Yinong Xie ◽  
Xueying Liu ◽  
Yijun Cai ◽  
Jinfeng Zhu
Keyword(s):  
Magnetic Resonance ◽  
High Performance ◽  
Uv Light ◽  
Light Trapping ◽  
Normal Incidence ◽  
Resonant Absorption ◽  
Base Layer ◽  
Absorption Enhancement ◽  
Monolayer Graphene ◽  
Polarization Insensitive

Abstract With the aim of improving UV light trapping capability in monolayer graphene, a metamaterials absorber is proposed, which exhibits the polarization-insensitive feature due to the geometrical symmetry. Through the functional combination of magnetic resonance and UV mirror, the absorption of unpolarized UV light in monolayer graphene can reach 99.5% under normal incidence. The absorption enhancement is induced by the magnetic resonance mode between the dielectric silica nanomesh and the calcium fluoride base layer. The effects of geometric parameters on the absorption spectra are systematically investigated. By optimizing the metamaterials design, two distinct resonant absorption peaks can be excited simultaneously for monolayer graphene. Our work paves the way for applications on high-performance UV metamaterials devices by using two-dimensional materials.

scholarly journals Broadband transmission-line illusions based on transformation electromagnetic

2019 ◽  
Vol 6 ◽  
pp. 23
Author(s):  
Tsutomu Nagayama ◽  
Atsushi Sanada
Keyword(s):  
Transmission Line ◽  
Incident Angle ◽  
Near Field ◽  
Homogeneous Medium ◽  
Field Measurements ◽  
Dielectric Substrate ◽  
Frequency Range ◽  
Microwave Frequencies ◽  
Intrinsic Nature ◽  
Line Technology

We demonstrate broadband transmission-line illusions based on transformation electromagnetics at microwave frequencies by using the distributed full-tensor anisotropic medium. Due to an intrinsic nature of the non-resonant unit cell of the medium, the illusions operate from DC to an upper limit frequency where the homogeneous medium approximation holds. Two-dimensional groove and bump illusion media mimicking scattered waves by an original groove and a bump are designed. Their broadband and incident angle independent operations are confirmed by circuit simulations. The groove illusion medium is implemented on a dielectric substrate with microstrip-line technology, and it is confirmed experimentally by near-field measurements that the illusion medium well mimics scattered waves by the original groove in the broadband frequency range from 2.60 GHz to 4.65 GHz.

scholarly journals Dual-Tunable Broadband Terahertz Absorber Based on a Hybrid Graphene-Dirac Semimetal Structure

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1096
Author(s):  
Jiali Wu ◽  
Xueguang Yuan ◽  
Yangan Zhang ◽  
Xin Yan ◽  
Xia Zhang
Keyword(s):  
Fermi Energy ◽  
Incident Angle ◽  
Normal Incidence ◽  
Surface Conductivity ◽  
Chemical Doping ◽  
Absorption Bandwidth ◽  
Terahertz Absorber ◽  
Dirac Semimetal ◽  
High Absorption ◽  
Broadband Terahertz

A dual-controlled tunable broadband terahertz absorber based on a hybrid graphene-Dirac semimetal structure is designed and studied. Owing to the flexible tunability of the surface conductivity of graphene and relative permittivity of Dirac semimetal, the absorption bandwidth can be tuned independently or jointly by shifting the Fermi energy through chemical doping or applying gate voltage. Under normal incidence, the device exhibits a high absorption larger than 90% over a broad range of 4.06–10.7 THz for both TE and TM polarizations. Moreover, the absorber is insensitive to incident angles, yielding a high absorption over 90% at a large incident angle of 60° and 70° for TE and TM modes, respectively. The structure shows great potential in miniaturized ultra-broadband terahertz absorbers and related applications.

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