54 results about "Tunable metamaterials" patented technology

A tunable metamaterial has a two dimensional array of resonant annular ring elements; and a plurality of voltage controllable electrical tuning elements disposed in or adjacent openings in each of said ring elements, each of said voltage controllable electrical tuning element ohmically contacting portions of only one of said ring elements. The voltage controllable electrical tuning elements may comprise highly doped semiconductor tunnel diodes, or the charge accumulation layer at the semiconductor/insulator interface of a metal-insulator-semiconductor structure, or nanoelectromechanical (NEMs) capacitors. The tunable metamaterial may be used, for example, in an optical beam steering device using the aforementioned tunable optical metamaterial in which a free-space optical beam is coupled into a receiving portion of a plane of the optical metamaterial and is steered out of a transmitter portion of the plane of the optical metamaterial in controllable azimuthal and elevational directions. The tunable metamaterial additionally has other applications.

The invention provides a tunable metamaterial absorber based on a phase-change material. The phase-change material is induced into a metamaterial based on multilayer structures to enable a working band which absorbs spectra to have a tunability so as to solve the technical problem that the absorber is narrow in spectrum absorption range. According to the tunable metamaterial absorber based on the phase-change material, by means of the characteristic that the dielectric coefficient of the phase-change material changes with the changes of an additional electric field or a temperature, the tunability for the absorber to absorb the spectra is achieved, and the maximum amplitude of accommodation can reach 900 nm.

The invention discloses a dielectric-based broadband tunable metamaterial wave-absorbing body and relates to the field of wave-absorbing materials and metamaterials. An electromagnetic wave-absorbingunit is formed by combining a soil material with a dielectric substrate on which a conductive thin film is pasted; and impedance matching is achieved through the electromagnetic wave-absorbing unit and a free space to achieve a relatively good wave-absorbing effect. The metamaterial wave-absorbing body is formed by periodically arranged wave-absorbing units and comprises the dielectric substrate,the soil material and the conductive thin film clung to the dielectric substrate. Square holes which are circular in inside are firstly engraved into the dielectric substrate, and then the soil material is embedded into the holes of the dielectric substrate and is in contact with the conductive thin film. By using the characteristic that the soil material has a high dielectric loss along with thechange of the water content in a microwave frequency band, the wave-absorbing bandwidth can be significantly increased under the condition of a relatively small thickness; main raw materials are easyto obtain and the metamaterial wave-absorbing body is eco-friendly, simple in structure, mature in preparation process, low in cost and suitable for large-scale production; and the wave-absorbing effect of the metamaterial wave-absorbing body can be adjusted through changing the water content of the soil material, so that operation is more convenient and concise.

A tunable electromagnetic device includes at least two overlapping metamaterial layers, wherein the metamaterial layers are selectively tunable by patterned conductive structures that are parts of the metamaterial layers. By selectively altering the properties of the metamaterial layers with the patterned conductive structures, the frequency response of the electromagnetic device can be controlled, to selectively let electromagnetic energy of certain frequencies pass through, or alternatively to prevent pass-through of substantially all frequencies of electromagnetic energy. In addition the frequencies for which electromagnetic energy passes through may be altered by controlling one or more of the tunable metamaterial layers. The tunable electromagnetic device may be used to selectively shield radar or other types of sensors, for example being used as all or part of the skin of a vehicle or other object.

One or more techniques are disclosed for a method for functionalized a graphitic material comprising the steps of: 1) providing a graphitic material; 2) providing a first molecule comprising a first group, a spacer, and a second group; 3) providing a second molecule comprising a third group, a spacer, and a fourth group, wherein said third group is a different group from said first group; and 4) bonding the first molecule and the second molecule to the graphitic material. Also disclosed is a tunable material composition comprising the functionalized carbon nanotubes or functionalized graphene prepared by the methods described herein.

The present disclosure describes the design and fabrication of a Terahertz (THz) beam steering device and a multifunctional patternless flat lens using electro-optic tunable fishnet materials (TFMM) to create a portable THz imaging system. The THz beam steering device and multifunctional patternless flat lens utilize a tunable resonant frequency of TFMM (with a negative refraction index) to achieve a maximum beam steering angle (field of view) and beam modulation. The portable THz scanning system is made by combining the TFMM beam steering device with a pair of continuous wave (CW) photomixer modules powered by two tunable CW lasers with built-in optical isolators, a fiber-optic beam combination and a multifunctional flat lens.

The present invention relates to liquid-crystalline media comprising one or more compounds of formula T as defined in claim 1, and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas (e.g. phased array antennas).

The invention relates to an isothiocyano group-containing naphthalene series liquid crystal monomer compound, and belongs to the technical field of liquid crystal materials, the structural formula of the liquid crystal monomer compound is shown as follows: R1 and R2 are independently selected from any one of alkyl and alkoxy; x is any one of a phenyl group, a biphenyl group, a benzyne group and a biphenyl alkynyl group. The naphthalene series liquid crystal monomer compound containing the isothiocyano group is applied to a liquid crystal composition, a liquid crystal display and a high-frequency technical component, and the high-frequency technical component is a liquid crystal-based antenna element, a phase shifter, a tunable optical filter or a tunable metamaterial structure. The naphthalene-series liquid crystal compound containing the isothiocyano group has a relatively high birefringence, a relatively wide nematic phase temperature, relatively high anisotropy and dielectric constant and capability of improving the performance of a liquid crystal component, and the clearing point of the liquid crystal component can be improved.

The present invention belongs to the infrared and terahertz band modulator and detector technical field and discloses a mechanical movement-based tunable metamaterial structure and a making method thereof. The mechanical movement-based tunable metamaterial structure comprises a fixed graphic structure, a metamaterial structure, a fixing box and a micro-displacement controller; the fixing box comprises a frame with an opening formed at the top and a hole formed at the first side; the metamaterial structure is placed in the fixing box; the fixed graphic structure is embedded in the opening of the top end of the fixing box so as to be fixed; the micro-displacement controller comprises a U-shaped frame and a micrometer caliper arranged at one end of the U-shaped frame; one end of the U-shaped frame is fixed at the second side surface of the outer side of the fixing box; the rotation shaft of the micrometer caliper contacts with the metamaterial structure; and the micrometer caliper controls the metamaterial structure through the rotation shaft so as to make the metamaterial structure move along a direction opposite to the first side surface and second side surface of the fixing box, so that relative micro-displacement of the fixing graphic structure and the metamaterial structure occurs, and therefore, the resonance peak frequency of the metamaterial can be modulated and absorbed.

The invention provides a tunable metamaterial optical tweezer based on liquid crystal material. By introducing the liquid crystal material in the multilayer structure-based metamaterial, the birefringence and the dielectric coefficient of the liquid crystal material are changed, and an optical trapping force variable in direction and size is generated, thus, accurate capturing and selection to the biomolecules in different sizes are realized. According to the invention, based on the character that the birefringence and the dielectric coefficient of the liquid crystal material vary with the change of the external electric field or the temperature, the tunable function of the metamaterial-based optical tweezer is realized. The optical tweezer has the characteristics of small volume, high capturing force, high stability and so on.

The invention discloses a double-absorption-peak adjustable metamaterial wave-absorbing body based on liquid crystals. Each wave-absorbing unit comprises both upper and lower layer medium substrates;liquid crystal layers are injected into gaps between the upper and lower layer medium substrates; a metal resonant unit is arranged on the lower surface of each upper layer medium substrate; each metal resonant unit comprises a plurality of short dipole metal patches which are sequentially connected in series and a plurality of long dipole metal patches which are sequentially connected in series;the plurality of short dipole metal patches which are sequentially connected in series are conected with a first metal electrode by metal wires; and the plurality of long dipole metal patches which are sequentially connected in series are connected with a second metal electrode by metal wires. The double-absorption-peak adjustable metamaterial wave-absorbing body has double absorption frequencies;by powering up different electrodes, the variation of either of absorption peak frequencies can be limited within a small range, and large-range regulation is implemented for the other absorption peak frequency; and according to the double-absorption-peak adjustable metamaterial wave-absorbing body disclosed by the invention, under a perpendicular incident wave, when any one resonant point is regulated, absorptivity of over 93% can still be kept.

The present disclosure relates to a tunable waveguide system comprising a waveguide configured to guide radio waves in at least two dimensions, and an electronically tunable metamaterial configured to tune the radio waves by electronically changing its dielectric and/or conductive characteristics. The present disclosure further relates to a radar antenna system.

The invention discloses a tunable metamaterial wave absorber based on multiple dielectric materials. The tunable metamaterial wave absorber structurally comprises a bottom-layer metal reflecting boardand a multilayer structure above the metal board, the multilayer structure comprises three layers of dielectric substrates and resonance units above each layer of dielectric substrate, the resonanceunits coated with high-resistance surfaces are arranged above the first layer of dielectric substrate and the third layer of dielectric substrate, and a solid-state plasma resonance unit is arranged above the second layer of dielectric substrate. The solid-state plasma resonance unit has two working states, namely an excitation state and a non-excitation state. The wave absorber has a very good absorption effect on TE polarized waves and TM polarized waves, by coating the high-resistance surfaces on the resonance units above the first layer of dielectric substrate and the third layer of dielectric substrate, the ultra-wideband absorption of the wave absorber can be realized, and the excitation of different resonance units can be realized by controlling the excitation areas of the resonanceunits formed by the solid-state plasmas in a programming manner, so that the tunable absorption of the wave absorber is realized.

The invention relates to a programmable waveguide based on an adjustable metamaterial. The waveguide comprises an upper substrate, a lower substrate, a metamaterial layer and a liquid crystal. The metamaterial layer is located on the lower substrate and is composed of superatoms distributed on the lower substrate. The liquid crystal fills the gap between the upper substrate and the lower substrateand wraps the superatoms. The liquid crystal is regulated and controlled by programming an external driver, so that Mie resonance of light in the metamaterial is changed, finally equivalent refractive index distribution is changed, and switching of waveguide functions is achieved. Compared with a traditional programmable waveguide, the programmable waveguide has the advantages that a new thoughtis provided in the aspect of working principle, higher transmission efficiency and energy utilization rate are achieved in the aspect of transmission performance, and higher programming freedom degreeand wider application direction are achieved.

The invention discloses a tunable metamaterial filter based on mechanical adjustment. The filter is composed of two planar metamaterials parallel to each other. The two planar metamaterials have the same resonant structure distribution cycle and arrangement direction. When relative positions of the metamaterials are changed by using a mechanical structure, a coupling state between resonant structures is changed, so that the resonant frequency is changed. The filter disclosed by the invention can be processed and assembled by using the conventional microstructure processing technology, and support of an MEMS (Micro-electromechanical Systems) technology is not needed, so the processing cost is greatly reduced. Meanwhile, the filter disclosed by the invention is wide in tunable range, and quality factor variation in the tuning process is small. The tunable metamaterial filter disclosed by the invention is applicable to microwave, Terahertz wave and light wave bands.

An active coding adjustable metamaterial system for broadband vibration isolation of a low frequency domain comprises at least two coding adjustable metamaterial super-cell modules which are connectedvertically; each metamaterial super-cell module forms a plane structure through a plurality of metamaterial unit cells distributed in sequence periodically; each metamaterial unit cell has an adjustable local resonance frequency, and comprises a substrate and an elastic element and a mass block connected with the elastic element, and the elastic element and the mass block are arranged in the substrate; and a plurality of unit cells form an adjustable "mass-rigidity-damping-substrate" system overall. According to the active coding adjustable metamaterial system, by adopting a joint coding adjustable technical means with equivalent rigidity and equivalent mass, a 3D printing technology and an active control strategy are combined, and the proposed active coding adjustable metamaterial systemhas the advantages of a structural module, small size, low cost, wide working frequency band, flexible control, etc.

The invention discloses a tunable metamaterial antenna for a wireless power transmission system. The overall size of the material is 75mm*75mm*5mm. The structure is small and compact. After an hfss simulation analysis, two metamaterial structures are used. On the basis of combination of the two metamaterial structures, a three-dimensional mode is formed in space; and metamaterial arrays are arranged on xoy, yox, and xoz planes. Therefore, the directivity of the antenna is improved obviously on the same size condition. The tunable metamaterial antenna has the following beneficial effects: firstly, the antenna is manufactured by using a pcb engraving printing machine, so that the manufacturing is carried out conveniently and the process is simple and mature; secondly, the metamaterial structure has the small size and is placed between a transmitting coil and a receiving coil of wireless charging, so that the usage becomes convenient; and thirdly, the metamaterial has the excellent property, the propagation direction of the electromagnetic wave is changed, the directional coefficient is increased, and the directivity of the antenna from the transmitting coil to the receiving coil is enhanced.

The invention provides a pair of PCM (phase-change material)-based tunable metamaterial optical tweezers. A PCM is introduced into a metamaterial based on a multilayer structure so as to change the dielectric coefficient of the PCM and generate an optical trapping force with changeable direction and strength, so that biomolecules in different sizes can be accurately grabbed and selected. According to the invention, the characteristic that the dielectric coefficient of the PCM changes along with the change of an additional electric field or temperature, so that the tunable function of the optical tweezers based on the metamaterial is achieved. The pair of optical tweezers has the characteristics of small size, large grabbing force, high stability and the like.

A self-aligned tunable metamaterial is formed as a wire mesh. Self-aligned channel grids are formed in layers in a silicon substrate using deep trench formation and a high-temperature anneal. Vertical wells at the channels may also be etched. This may result in a three-dimensional mesh grid of metal and other material. In another embodiment, metallic beads are deposited at each intersection of the mesh grid, the grid is encased in a rigid medium, and the mesh grid is removed to form an artificial nanocrystal.

The invention relates to a metamaterial microwave antenna which comprises a metamaterial panel, a feed source, a first stage subreflector and a second stage subreflector, wherein a first center hole is formed in the center of the metamaterial panel, and a second center hole is formed in the center of the second stage subreflector; the first stage subreflector is embedded in the first center hole of the metamaterial panel, and the feed source is embedded in the second center hole of the second stage subreflector. The metamaterial microwave antenna provided by the invention uses a metamaterial for converging electromagnetic wave properties and a double-curved surface like type metamaterial and a rotating elliptical surface are used as the first stage subreflector and the second subreflector respectively, so that the antenna is enabled to have a more compact structure and have the same effect with that of a long-focus microwave antenna; the energy distribution on a diametric plane is adjusted, so that the aperture efficiency of the antenna is improved and an excellent far-field radiation field response is achieved; moreover, the processing difficulty is small and the cost is low.