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A Novel Broadband Bi-Functional Metasurface for Vortex Generation and Simultaneous RCS Reduction
摘要： In this paper, a broadband bi-functional metasurface is presented with capabilities of generating vortex beam for y-polarization and reducing the backward radar cross section (RCS) for x-polarization. With careful optimization, a meta-atom is first designed to control reflection phases for orthogonally polarized wave independently. Then, an integrated phase profile is employed to convert y-polarized spherical wavefront into a vortex spiral one, shaping a vortex high gain beam in the far-field region. By arranging a checkerboard-like phase profile onto the surface for x-polarization, the reflected wave in the backward direction will be canceled, consequently leading to the backward RCS reduction for x-polarization. Combining the above-mentioned cases into a whole, a compact bi-functional metasurface is designed, simulated, physically implemented, and finally measured. In good agreement with the simulated results, the measured ones show that the RCS reduction of 10 dB for x-polarization in comparison with a same-sized metallic plate can be realized over a 67.7 % frequency bandwidth (9–18.2 GHz). Besides, high-efficiency vortex beam conversion effect for y-polarization over a broad range of 11.2–18.2 GHz (47.6%) can also be observed from the measured results.
关键词： vortex beam generator,RCS reduction,Metasurface,bi-functional
更新于2025-09-09 09:28:46
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RCS Reduction and Gain Enhancement for the Circularly Polarized Array by Polarization Conversion Metasurface Coating
摘要： High-gain, the ultra-wide band circularly polarized (CP) array with low radar cross section (RCS) is proposed based on (UWB) polarization conversion metasurface (PCM) coating. A chessboard-like coating is formed by a mess of arrow-shaped PCM elements which have UWB and high polarization conversion ratio. The coating is distributed beneath the dipoles and behaving as a reflector. With the PCM beneath each dipole, the CP radiation is achieved and enhanced in a low profile by the radiating wave and the reflected wave, which have equal amplitude and 90° phase difference. With the chessboard-like coating, the incident wave is converted into the equal amplitude and out-of-phase reflected waves, which will cancel each other to reduce the backward scattering. The performances of the array are validated by both simulations and measurements. The results show that the left-hand CP radiation is achieved in 11.25 GHz to 12.31 GHz with the RCS being reduced for more than 4.8 dB in 10.5 GHz to 35.1 GHz.
关键词： high gain,circular polarization,low profile,radar cross section (RCS),polarization conversion metasurface (PCM)
更新于2025-09-09 09:28:46
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Recent Advances in Tunable and Reconfigurable Metamaterials
摘要： Metamaterials are composed of nanostructures, called artificial atoms, which can give metamaterials extraordinary properties that cannot be found in natural materials. The nanostructures themselves and their arrangements determine the metamaterials’ properties. However, a conventional metamaterial has fixed properties in general, which limit their use. Thus, real-world applications of metamaterials require the development of tunability. This paper reviews studies that realized tunable and reconfigurable metamaterials that are categorized by the mechanisms that cause the change: inducing temperature changes, illuminating light, inducing mechanical deformation, and applying electromagnetic fields. We then provide the advantages and disadvantages of each mechanism and explain the results or effects of tuning. We also introduce studies that overcome the disadvantages or strengthen the advantages of each classified tunable metamaterial.
关键词： plasmonics,metasurface,indium tin oxide,wavefront engineering,phase change material,color filter,perfect absorber,graphene
更新于2025-09-09 09:28:46
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A Miniaturized and High Gain Double-Slot Vivaldi Antenna Using Wideband Index-Near-Zero Metasurface
摘要： In this paper, a wideband, miniaturized, and high gain double-slot Vivaldi antenna is proposed. First, a corner cutting technique is adopted to broaden the frequency band. Second, a pair of defected ground slots are added to the edges of the antenna to extend the low-end frequency limitation from 2.27GHz to 1.15 GHz, which provides a great design freedom. Third, a novel unit cell of an index-near-zero metasurface is proposed in our design. The unit cell is a two-stub-loaded split-ring resonator, which has a compact size, a wide frequency band, and a good reflection coefficient. The gain of the double-slot Vivaldi antenna is improved over a wide frequency band by the inclusion of the index-near-zero metasurface in the aperture, without changing the overall dimensions or compromising the whole frequency band performance of the antenna. Finally, to verify the design method, an ultra-wideband double-slot Vivaldi antenna with defected ground slots and metasurface was fabricated and measured. The circuit has an overall size of 0.76 λg × 0.41 λg × 0.005 λg. The modified antenna exhibits a measured gain of 0.7–14 dBi over the frequency band of 1.13–12 GHz.
关键词： index-near-zero,Vivaldi antenna,Defected ground slot,high gain,metasurface
更新于2025-09-09 09:28:46
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Reconfigurable metasurface for multiple functions: magnitude, polarization and phase modulation
摘要： A novel reconfigurable metasurface for multiple functions is designed and investigated. The lattice of the metasurface is proposed to realize integrated absorption and polarization rotation and named as polarization conversion absorber (PCA). Then, lattices are arranged together to realize a certain function. Due to the independence of each lattice, the metasurface can present different performance based on different arrangement principle. Magnitude, polarization and phase modulation can be presented by manually arranging metasurface with 6 × 6 lattices. Both simulations and measurements prove that the proposed method provides a simple, flexible and effective strategy for multifunctional metasurface design.
关键词： phase modulation,magnitude modulation,polarization modulation,reconfigurable metasurface,polarization conversion absorber
更新于2025-09-09 09:28:46
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A multi-functional vortex beam generator based on transparent anisotropic metasurface
摘要： Vortex beam generators are increasingly in demand for their enormous potential in improving communication capability. Along with the continuous integration of electronic product, devices with single function can not satisfy the requirements of the people. Here, by employing an anisotropic metasurface (MS), we propose a transparent multi-functional vortex beam generator to obtain vortex beams with reconfigurable polarization status. An anisotropic element is firstly optimized to control x- and y-polarized wave independently, and then is applied to assemble a vortex beam generator that is not only able to convert spherical wavefront into a vortex one but also able to transform linearly polarized mode into the circular polarized counterpart. Interestingly, the polarized status of the generated vortex beam changes from x-polarization to left hand circularly polarization (LHCP) to y-polarization and finally to right hand circularly polarization (RHCP) when the spot source is rotated with different angles. For verification, the prototype of the practical configuration is fabricated and measured. Coinciding well with the simulated results, the measured ones show that linearly polarized spherical wave has been converted into LHCP or RHCP vortex beams with operating efficiency of 85.8% or 83.3% respectively.
关键词： vortex beam,multi-function,metasurface
更新于2025-09-09 09:28:46
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Microwave edge modes on a metasurface with glide symmetry
摘要： In this work we study planar metasurfaces comprised of two layers of hexagonal arrays of circular metal patches. This two-layer geometry supports a bound surface wave that propagates along the x direction. In our study, each metasurface is in?nitely periodic in one direction (x) but only a few periods wide in the orthogonal direction (y). Through experiments and modeling we ?nd evidence of a localized edge mode whose existence is dependent on the relative alignment of the two layers. This edge mode is used to guide the propagation of electromagnetic energy around both triangular and hexagonal shapes.
关键词： metasurface,electromagnetic energy propagation,glide symmetry,microwave edge modes
更新于2025-09-09 09:28:46
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Blazed Metasurface Grating with Handedness Preservation for Circularly Polarized Incident Wave
摘要： A new blazed metasurface grating for circularly polarized (CP) incident wave operating at 10 GHz is proposed. Such a structure can provide strong auto-collimation for the CP incident wave. Unlike the conventional scatterer, which typically reverses the handedness of the incident CP wave upon re?ection, the proposed grating can preserve the handedness. The auto-collimation blazing effect and handedness preservation are achieved by a specially designed reactive impedance surface, which allows independent response controls to transverse electric (TE) and transverse magnetic (TM) polarizations. The proposed idea is demonstrated by simulations and veri?ed by experiments. Comparisons with conventional sawtooth grating are made through measurements.
关键词： metasurface,circularly polarized wave,Littrow,blazed,auto-collimation,handedness preservation
更新于2025-09-09 09:28:46
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The photonic candle
摘要： Using light to manipulate small particles has proven an indispensable tool for ‘tweezing’, sorting and force measurements. To achieve effective optical traps with high ‘stiffness’, researchers often go to great lengths to tailor light fields, for example by using holographic elements. Now, Aliaksandra Ivinskaya and colleagues from Russia, the USA, the UK and Israel predict that small particles can be manipulated using a plane wave of light and a simple flat surface of an anisotropic media supporting hyperbolic modes. Their hyperbolic metamaterial is composed of metal and dielectric layers and is potentially less affected by losses and offers more broadband capability than purely plasmonic approaches. In their theoretical study a small dielectric sphere near a hyperbolic metamaterial is considered. The particle is sufficiently small to provide the required momentum to excite both surface plasmon and bulk hyperbolic waves from incident plane waves. Strong optical pulling forces were predicted over the 400–800 nm wavelength range thanks to the broadband high density of states of hyperbolic modes.
关键词： hyperbolic modes,nano-optics,optical manipulation,metasurface,plasmon
更新于2025-09-09 09:28:46
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Ultrawide tunability
摘要： Using light to manipulate small particles has proven an indispensable tool for ‘tweezing’, sorting and force measurements. To achieve effective optical traps with high ‘stiffness’, researchers often go to great lengths to tailor light fields, for example by using holographic elements. Now, Aliaksandra Ivinskaya and colleagues from Russia, the USA, the UK and Israel predict that small particles can be manipulated using a plane wave of light and a simple flat surface of an anisotropic media supporting hyperbolic modes. Their hyperbolic metamaterial is composed of metal and dielectric layers and is potentially less affected by losses and offers more broadband capability than purely plasmonic approaches. In their theoretical study a small dielectric sphere near a hyperbolic metamaterial is considered. The particle is sufficiently small to provide the required momentum to excite both surface plasmon and bulk hyperbolic waves from incident plane waves. Strong optical pulling forces were predicted over the 400–800 nm wavelength range thanks to the broadband high density of states of hyperbolic modes.
关键词： hyperbolic modes,nano-optics,optical manipulation,metasurface,plasmon
更新于2025-09-09 09:28:46