摘要：
The metasurface is a functional film device based on a subwavelength structure, which has a strong light field control ability and has the advantages of ultrathin, low loss, and easy manufacturing. However, realizing a multifunctional metasurface, yet simple enough to design, manufacture, and thin is still a challenge. In this article, we propose a novel metasurface with negligible thickness as a beam splitter, which can achieve half transmission and half reflection of the incident wave at the same frequency. It also controls the polarization of circularly polarized electromagnetic (EM) waves in the transmission mode. A broadband operation can be achieved based on the geometric phase theory, and the phase control can be achieved by azimuth rotation of the structure. The numerical results of the metasurface are in good agreement with the experimental results in the measured frequency range. The ultrathin multifunctional metasurface realized by the geometric phase principle provides an important stepping stone for simple optical devices and can be extended to a higher frequency range.
摘要：
In this paper, a polarization-sensitive absorption and transmission polarization conversion multifunctional metasurface is designed. Based on the principle of Fabry-Borot antenna, the modulation of electromagnetic waves with different polarizations is realized. Receiver-transmitter structure consisting of rectangular metal patches on the front and back sides . Cross-polarization conversion of Y-polarized waves was achieved at 8.9-15.2 GHz. In combination with the open-slit elliptical structure, selective absorption of X-polarization can be achieved, thus realizing the radar cross-section(RCS) reduction of the target. The absorption operates in the frequency band of 8.3-13.9 GHz. Electromagnetic waves of different polarizations do not affect each other in the modulation of the same structure and operate in almost the same frequency band. To verify the proposed structure, the relevant parameters were optimized and measured. The experimental results match with the simulation results, and the design can be used for radome and electromagnetic stealth.
期刊：
Journal of Applied Physics,2022年132(13):133103 ISSN：0021-8979
通讯作者：
Helin Yang
作者机构：
[Li, Shangru; Yang, Helin; Zhou, Xiaofeng; Wu, Jiong; Yang, Yuejie] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Chen, Jiao] Huanggang Normal Univ, Sch Phys & Telecommun, Huanggang 438000, Peoples R China.
通讯机构：
[Helin Yang] T;The College of Physical Science and Technology, Central China Normal University , Wuhan 430079, China
摘要：
In this paper, we introduce a dual-broadband dual-function polarization conversion metasurface, which can convert a linearly polarized (LP) incident electromagnetic wave into a cross-polarized LP wave and a circularly polarized wave, effectively, in different bands. The numerical simulations and experiments show that the metasurface can be used as a high-efficiency cross-polarization converter from 5.50 to 12.4 GHz, where the polarization conversion ratio is greater than 0.9 with a fractional bandwidth of 77.1%. Simultaneously, it can convert the LP incident wave into a right-handed circularly polarized wave from 13.50 to 19.75 GHz, where the axis ratio is lower than 3 dB and the fractional bandwidth is 37.4%. A honeycomb is used as a support layer instead of air gaps, which improves the efficiency of cross-polarization conversion and broadens the bandwidth of linear to circular conversion. To reveal the conversion mechanism of the proposed polarization converter, the surface current is analyzed. Finally, we fabricated and tested it, and the experimental results are in line with the simulation results.
作者机构：
[Yang, Helin; Xiang, Tianyu; Wu, Jiong] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Xiang, Tianyu; Lei, Tao; Wang, Jianwei; Peng, Man] Guizhou Normal Univ, Sch Big Data & Comp Sci, Guiyang 550000, Peoples R China.;[Lei, Tao; Wang, Jianwei] Southeast Univ, State Key Lab Millimeter Waves, Nanjing 210000, Peoples R China.
摘要：
The toroidal dipole is implemented by abundant and bio-friendly water with a high dielectric constant in the microwave range. A Fano resonance, with high Q-factor up to 152, resulting from enhanced fancy toroidal dipole could be stimulated at 1.65 GHz. Analysis of the induced current and near-and far-field shows that energy can be concentrated in distilled water, and the intriguing toroidal dipole plays a decisive role in resonance. Under different size parameters and conductivity of water-based metamaterial, the toroidal excitation and its influence on transmission characteristics are discussed. The toroidal dipole excited in distilled water might be of great significance for designing ultra-sensitive sensors, absorbers, and slow-light devices.(c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
作者机构：
[Cao, Miao; Gao, Lina; Huang, Xiaojun] Xian Univ Sci & Technol, Coll Commun & Informat Engn, Xian 710054, Peoples R China.;[Li, Xiaoyan] Northwestern Polytech Univ, Coll Phys Sci & Technol, Xian 710129, Peoples R China.;[Guo, Linyan] China Univ Geosci, Sch Geophys & Informat Technol, Beijing 100083, Peoples R China.;[Yang, Helin] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
通讯机构：
[Xiaojun Huang] C;[Xiaoyan Li] A;College of Communication and Information Engineering, Xi’an University of Science and Technology, Xi’an 710054, China<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>College of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
摘要：
Water-based absorbers have shown great development potential in the past few years. In this paper, an all-dielectric transparent bi-directional water-based broadband metamaterial absorber is designed. The simulation results indicate that absorptance of the absorber is over 90% in 5.7-41.6 GHz, and its fraction bandwidth is 151.8%. The experimental results are greatly consistent with the simulations. The designed absorber has excellent performances of polarization insensitivity, oblique incidence stability and thermal stability. When the absorptance is more than 0.8, the maximum incident angle reaches 40 degrees in TE mode and is over 60 degrees in TM mode. In 0-80 degrees C, absorptance of the absorber is hardly changed. Because of the optical transparency of the designed absorber, it can be extensively used in stealth window weapons and electromagnetic compatibility equipment.
期刊：
Journal of Physics D: Applied Physics,2022年55(45):455106 ISSN：0022-3727
通讯作者：
Helin Yang
作者机构：
[Wang, Yang; Yang, Helin; Liu, Shanshan; Wu, Jiong; Ding, Xiaoxia] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Wang, Youcheng; Chen, Shiju] Sci & Technol Complex Syst Control & Intelligent, Beijing 100074, Peoples R China.
通讯机构：
[Helin Yang] C;College of Physical Science and Technology, Central China Normal University, Wuhan 430079, People's Republic of China
关键词：
ultra-broadband;absorbers;honeycomb
摘要：
In this paper, a radar absorber with composite structure of metasurface/honeycomb is proposed. Carbon coating is used as a loss material, and honeycomb sandwich structure is used as a support layer to enhance mechanical strength. Introducing impedance matching layer in the top layer of honeycomb absorber can significantly improve the low-frequency absorption performance. The simulation results show that the absorption efficiency of the combined structure absorber can reach more than 90% in the frequency range of 3.65-17.3 GHz. We verified the simulation results through experiments. This method provides an idea for the design of ultra-wideband absorber and has a potential application prospect in stealth material design.
摘要：
This paper proposes a toroidal plasmons resonator composed of a slotted circle and a ring fed by a microstrip line. Multi-modes Mie resonances are well excited by the feed of the microstrip line. A toroidal magnetic field is demonstrated and analyzed by CST simulation at 14.318 GHz. The higher-order resonance shows higher sensitivity for permittivity sensing. By reconstructing the structure, the excited octupole has a high sensitivity of 3.68 GHz/RIU and quality factors of 340.6 with a ${Q}$ -factor of 340.6. The high sensitivity, high Q-factor, and compact size make it a good choice for sensing applications.
摘要：
Electromagnetic multipoles enable rich electromagnetic interactions in a metasurface and offer another degree of freedom to control electromagnetic responses. In this work, we design and experimentally demonstrate an optically transparent, flexible and broadband microwave metasurface absorber based on multipolar interference engineering. Different from previous works, the designed metasurface simultaneously supports fundamental electric dipole and high-order electric quadrupole mode, whose interference satisfies the back-scattering suppression condition based on the generalized Kerker effect and thus high absorption. The measurement results indicate that the fabricated metasurface exhibits a high average absorption of 89% in the microwave band from 4 GHz to 18 GHz, together with a good optical transparency. Our study offers an alternative approach fbr designing broadband microwave metasurface absorber, which is potentially applicable in electromagnetic shielding, radar stealth and energy harvesting. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
摘要：
A linear-to-linear polarization conversion metamaterial is proposed with a water -metal structure. The simulation results show that the proposed metamaterial design can achieve ultra-broadband and high-efficiency polarization conversion within the frequency range from 7.46 GHz to 14.84 GHz with a polarization conversion ratio over 90%. This metamaterial exhibits sensitivity to the incidence angle but not to and temperature. The physical mechanism of polarization conversion is analyzed based on the distributions of the surface current and the magnetic field. An experimental sample of the designed metamaterial is fabricated, assembled, and measured in such a way as to realize reflective polarization conversion. This work provides a significant stepping stone for water-based metamaterial design and polarization control.(c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
期刊：
Journal of Applied Physics,2022年132(22):223106 ISSN：0021-8979
通讯作者：
Helin Yang
作者机构：
[Cheng, Houyuan; Li, Yujun; Dai, Yilin; Yang, Helin; Fu, Yang; Wu, Jiong] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Wen, Dinge] China Ship Dev & Design Ctr, Sci & Technol Electromagnet Compatibil Lab, Wuhan 430064, Peoples R China.
通讯机构：
[Helin Yang] T;The College of Physical Science and Technology, Central China Normal University , Wuhan 430079, China
摘要：
A three-layer multifunctional metasurface structure is proposed to achieve polarization rotation, perfect polarization conversion, and asymmetric transmission. The design consists of mutually perpendicular rectangular patches, metal pillars, and open-slit metal sheets. By propagating the current through the metal pillars and changing the surface current direction, the dipole can be orthogonally steered to accomplish polarization conversion. The metal in the middle layer can be used to both improve the polarization conversion ratio and ensure high transmittance. The operating band of asymmetric transmission is 8.3-14.7 GHz, where the conversion ratio is above 90% in all of 9-14.2 GHz. In order to verify the proposed concept, the related parameters are designed and measured, the final experimental results match with the simulation results, and the design can be used in the radome, electromagnetic stealth. Published under an exclusive license by AIP Publishing.
作者机构：
[Zhang, Qinhe; Shen, Zhaoyang] China Three Gorges Univ, Hubei Prov Engn Technol Res Ctr Construct Qual Te, Yichang 443002, Peoples R China.;[Zhang, Qinhe; Zhao, Liang; Shen, Zhaoyang] China Three Gorges Univ, Coll Comp & Informat Technol, Yichang 443002, Peoples R China.;[Yang, Helin; Wu, Jiong] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Zhao, Liang] China Three Gorges Univ, Hubei Key Lab Intelligent Vis Based Monitoring Hy, Yichang 443002, Peoples R China.
摘要：
In this paper, a novel orthogonal dual-beam Vivaldi antenna loaded with metamaterial lenses (MLs) is designed as the original antenna. Then, we designed two simple water-based absorbers (WBAs) containers using 3D printing technology, which can be mounted on the ML. WBA filled with water can absorb electromagnetic waves radiated from antenna aperture, while empty WBA does not affect antenna radiation. The antenna radiation pattern can be reconstructed by selectively injecting water into WBAs. The proposed antenna can realize three radiation states in the operating frequency band, including radiation along the X direction and Y direction at the same time (state 1), radiation along X direction (state 2), and radiation along the Y direction (state 3). The proposed antenna has an operating frequency range from 3 GHz to 6 GHz, which realizes the coverage of the 5G sub-6 GHz main frequency band. Finally, the measured results of the antenna are consistent with the simulated. The work in this paper has potential application value in the 5G communication system and point-to-point communication system.
摘要：
A kind of compound optical lens (COL) inspired by metamaterials whose unit cell is a closed symmetric S-type resonator (CSSR) is designed to enhance the gain and directivity of the antipodal Vivaldi antenna (AVA). COL, composed of a plano-convex lens and a double-convex lens, can generate a very narrow beam with a half-power beamwidth of 11.2 degrees at 12 GHz. Traditional metamaterial lenses can only convert spherical waves into plane waves. Although the gain will increase, the beamwidth of the antenna is still very wide. COL can focus the plane wave transformed from the spherical wave, which makes the radiation beam extremely narrow. The proposed antenna has a -10 dB impedance bandwidth of 169.2% (1.0-12.0 GHz) and a -3 dB gain bandwidth of 133.3% (2.0-10.0 GHz) and a maximum gain enhancement of 5 dBi. The experimental results of the antennas agree with the simulation results. The proposed antenna is eventually a suitable candidate for wireless communications and radar applications.
