Metamaterials based on effective media can be used to produce a number of unusual physical properties(for example,negative refraction and invisibility cloaking)because they can be tailored with effective medium parame...Metamaterials based on effective media can be used to produce a number of unusual physical properties(for example,negative refraction and invisibility cloaking)because they can be tailored with effective medium parameters that do not occur in nature.Recently,the use of coding metamaterials has been suggested for the control of electromagnetic waves through the design of coding sequences using digital elements‘0’and‘1,'which possess opposite phase responses.Here we propose the concept of an anisotropic coding metamaterial in which the coding behaviors in different directions are dependent on the polarization status of the electromagnetic waves.We experimentally demonstrate an ultrathin and flexible polarization-controlled anisotropic coding metasurface that functions in the terahertz regime using specially designed coding elements.By encoding the elements with elaborately designed coding sequences(both 1-bit and 2-bit sequences),the x-and y-polarized waves can be anomalously reflected or independently diffused in three dimensions.The simulated far-field scattering patterns and near-field distributions are presented to illustrate the dual-functional performance of the encoded metasurface,and the results are consistent with the measured results.We further demonstrate the ability of the anisotropic coding metasurfaces to generate a beam splitter and realize simultaneous anomalous reflections and polarization conversions,thus providing powerful control of differently polarized electromagnetic waves.The proposed method enables versatile beam behaviors under orthogonal polarizations using a single metasurface and has the potential for use in the development of interesting terahertz devices.展开更多
The programmable metasurface has been proved to be an effective tool to dynamically tailor electromagnetic(EM)waves.However,how to achieve real-time and independent controls of circularly polarized(CP)waves in the tra...The programmable metasurface has been proved to be an effective tool to dynamically tailor electromagnetic(EM)waves.However,how to achieve real-time and independent controls of circularly polarized(CP)waves in the transmission and reflection spaces is still a challenge.To address this problem,we propose a full-space programmable CP metasurface,which can independently manipulate the CP waves in transmission and reflection spaces in real time by controlling the bias voltage.The polarization states of reflected and transmitted CP waves can be independently customized through elaborate meta-atom design.As a proof of concept,we designed,fabricated,and measured a full-space programmable CP metasurface that can realize copolarized reflection for righthanded circularly polarized(RCP)waves and cross-polarized transmission for left-handed circularly polarized(LCP)waves.Simulated and measured results verify that the wavefronts of reflected and transmitted CP waves can be independently manipulated in real time by reprogramming the reflection and transmission phase coding sequences.Based on the full-space programmable CP metasurface,a space-multiplexing wireless communication scheme is established,successfully delivering two different images along preset reflection and transmission channels.展开更多
Beam-frequency-scanning detection and point-to-point communication typically differ significantly in bandwidth and polarization characteristics,requiring two separate antennas in conventional designs.This paper propos...Beam-frequency-scanning detection and point-to-point communication typically differ significantly in bandwidth and polarization characteristics,requiring two separate antennas in conventional designs.This paper proposes a method to integrate a dual-mode radiation of narrowband circular polarization(CP)into a broadband linearly polarized(LP)beam-scanning leaky-wave antenna(LWA)using a full spoof surface plasmon polariton(SSPP)system.First,a grooved SSPP unit and its complementary structure are used with periodic mode modulation to achieve continuous vertically polarized(V-pol)dual-beam scanning from backward to forward.By periodically embedding spoof localized surface plasmon(SLSP)units,strong coupling between SLSPs and SSPPs is enabled under resonant conditions.Then,CP radiation is generated due to the rotating electric-field vectors of SLSPs.Experiment and simulation results demonstrate continuous V-pol beam scanning from−30°to 22°across 4.25–6.75 GHz,including effective broadside radiation.Notably,at 5.4 GHz,the antenna radiates right-handed circularly polarized(RHCP)and left-handed circularly polarized(LHCP)waves in opposite broadside directions.Compared with existing technologies,the insertable CP radiation allows the antenna to enable two significantly different operating modes,which can be applied in combined beam-scanning detection and narrowband satellite emergency communication,greatly improving system integration.展开更多
Information security plays an important role in every aspect of life to protect data from stealing and deciphering.However,most of the previously reported works were based on pure algorithm layer or pure physical laye...Information security plays an important role in every aspect of life to protect data from stealing and deciphering.However,most of the previously reported works were based on pure algorithm layer or pure physical layer encryptions,which have certain limitations in security.In this paper,a nondeterministic message encryption communication scheme is proposed based on a spin-space-frequency multiplexing metasurface(SSFMM),which integrates both algorithmic and physical layer encryptions,and can also produce multiple different ciphertexts for the same message to prevent the message from being cracked through frequency analysis,thus greatly enhancing the security of the information.To be specific,an SSFMM is first designed as a physical-layer meta-key,which can generate eight independent dot matrix holograms with different spin,space,and frequency characteristics.The target message is then encrypted based on these dot matrix holograms combined with algorithmic operations,and the encrypted message is converted into a quick response(QR)code for easy sending to the target users.Once the target user gets that QR code,he/she can scan it to obtain the encryption information,and then recover the target message according to the pre-agreed encryption protocol combined with the eight dot matrix holograms of SSFMM.Finally,the feasibility of the proposed encryption scheme was experimentally validated at the microwave frequency band.展开更多
基金supported by the National Science Foundation of China(61571117,61522106,61138001,61302018 and 61401089)Natural Science Foundation of the Jiangsu Province(BK2012019)the 111 Project(111-2-05).
文摘Metamaterials based on effective media can be used to produce a number of unusual physical properties(for example,negative refraction and invisibility cloaking)because they can be tailored with effective medium parameters that do not occur in nature.Recently,the use of coding metamaterials has been suggested for the control of electromagnetic waves through the design of coding sequences using digital elements‘0’and‘1,'which possess opposite phase responses.Here we propose the concept of an anisotropic coding metamaterial in which the coding behaviors in different directions are dependent on the polarization status of the electromagnetic waves.We experimentally demonstrate an ultrathin and flexible polarization-controlled anisotropic coding metasurface that functions in the terahertz regime using specially designed coding elements.By encoding the elements with elaborately designed coding sequences(both 1-bit and 2-bit sequences),the x-and y-polarized waves can be anomalously reflected or independently diffused in three dimensions.The simulated far-field scattering patterns and near-field distributions are presented to illustrate the dual-functional performance of the encoded metasurface,and the results are consistent with the measured results.We further demonstrate the ability of the anisotropic coding metasurfaces to generate a beam splitter and realize simultaneous anomalous reflections and polarization conversions,thus providing powerful control of differently polarized electromagnetic waves.The proposed method enables versatile beam behaviors under orthogonal polarizations using a single metasurface and has the potential for use in the development of interesting terahertz devices.
基金National Natural Science Foundation of China(62071117,62288101)Major Project of the Natural Science Foundation of Jiangsu Province(BK20212002)+2 种基金111 Project(111-2-05)Fundamental Research Funds for the Central Universities(2242023K5002)Jiangsu Specially-Appointed Professor.
文摘The programmable metasurface has been proved to be an effective tool to dynamically tailor electromagnetic(EM)waves.However,how to achieve real-time and independent controls of circularly polarized(CP)waves in the transmission and reflection spaces is still a challenge.To address this problem,we propose a full-space programmable CP metasurface,which can independently manipulate the CP waves in transmission and reflection spaces in real time by controlling the bias voltage.The polarization states of reflected and transmitted CP waves can be independently customized through elaborate meta-atom design.As a proof of concept,we designed,fabricated,and measured a full-space programmable CP metasurface that can realize copolarized reflection for righthanded circularly polarized(RCP)waves and cross-polarized transmission for left-handed circularly polarized(LCP)waves.Simulated and measured results verify that the wavefronts of reflected and transmitted CP waves can be independently manipulated in real time by reprogramming the reflection and transmission phase coding sequences.Based on the full-space programmable CP metasurface,a space-multiplexing wireless communication scheme is established,successfully delivering two different images along preset reflection and transmission channels.
基金National Natural Science Foundation of China(62401133,62071117,62288101)111 Project(111-2-05)+3 种基金Natural Science Foundation of Jiangsu Province(BK20230192)Science and Technology Research Funds of Wuxi TaihuLight Program(K20231007)Sichuan Province Engineering Research Center for Broadband Microwave Circuit High Density IntegrationYoung Elite Scientists Sponsorship Program by Jiangsu Association for Science and Technology.
文摘Beam-frequency-scanning detection and point-to-point communication typically differ significantly in bandwidth and polarization characteristics,requiring two separate antennas in conventional designs.This paper proposes a method to integrate a dual-mode radiation of narrowband circular polarization(CP)into a broadband linearly polarized(LP)beam-scanning leaky-wave antenna(LWA)using a full spoof surface plasmon polariton(SSPP)system.First,a grooved SSPP unit and its complementary structure are used with periodic mode modulation to achieve continuous vertically polarized(V-pol)dual-beam scanning from backward to forward.By periodically embedding spoof localized surface plasmon(SLSP)units,strong coupling between SLSPs and SSPPs is enabled under resonant conditions.Then,CP radiation is generated due to the rotating electric-field vectors of SLSPs.Experiment and simulation results demonstrate continuous V-pol beam scanning from−30°to 22°across 4.25–6.75 GHz,including effective broadside radiation.Notably,at 5.4 GHz,the antenna radiates right-handed circularly polarized(RHCP)and left-handed circularly polarized(LHCP)waves in opposite broadside directions.Compared with existing technologies,the insertable CP radiation allows the antenna to enable two significantly different operating modes,which can be applied in combined beam-scanning detection and narrowband satellite emergency communication,greatly improving system integration.
基金supported by the National Natural Science Foundation of China(62071117 and 62288101)the Project for Jiangsu Specially-Appointed Professor,the Major Project of the Natural Science Foundation of Jiangsu Province(BK20212002)+1 种基金the 111 Project(111-2-05)the Fundamental Research Funds for the Central Universities(2242023K5002).
文摘Information security plays an important role in every aspect of life to protect data from stealing and deciphering.However,most of the previously reported works were based on pure algorithm layer or pure physical layer encryptions,which have certain limitations in security.In this paper,a nondeterministic message encryption communication scheme is proposed based on a spin-space-frequency multiplexing metasurface(SSFMM),which integrates both algorithmic and physical layer encryptions,and can also produce multiple different ciphertexts for the same message to prevent the message from being cracked through frequency analysis,thus greatly enhancing the security of the information.To be specific,an SSFMM is first designed as a physical-layer meta-key,which can generate eight independent dot matrix holograms with different spin,space,and frequency characteristics.The target message is then encrypted based on these dot matrix holograms combined with algorithmic operations,and the encrypted message is converted into a quick response(QR)code for easy sending to the target users.Once the target user gets that QR code,he/she can scan it to obtain the encryption information,and then recover the target message according to the pre-agreed encryption protocol combined with the eight dot matrix holograms of SSFMM.Finally,the feasibility of the proposed encryption scheme was experimentally validated at the microwave frequency band.
