73results about How to "Polarization insensitive" patented technology

The invention relates to an electromagnetic shielding optical window with a two-double pane metal grating structure and belongs to the optical transparent piece electromagnetic shielding technical field; the electromagnetic shielding optical window is formed by placing two layers of pane metal gratings or metal silk screens with the same structure parameters on two sides of the optical window or a transparent underlay in parallel; a side length of a pane of the two-double pane metal grating is greater than two times of a side length of a pane of the prior monolayer pane metal grating; the space between two layers of pane metal gratings is two to four times of the side length of the pane; compared with the prior monolayer pane metal grating, the optical window adopting the two-double pane metal grating structure does not reduce light transmittance, substantially improves the shielding efficiency of microwaves and millimeter waves, solves the problems that the high light transmittance and strong electromagnetic shielding efficiency can not simultaneously considered in the prior optical window electromagnetic shielding technology and is suitable for electromagnetic shielding in aerospace equipment, security facilities, medical diagnostic instruments and other military and civil optical transparent pieces.

The invention discloses a method for achieving wavefront modulation based on a dielectric conformal metasurface, and belongs to the technical field of micro-nano optics and holography. The implementation method comprises the following steps of designing a unit structure of the metasurface, wherein the metasurface is composed of dielectric circular nanopillar arrays with different geometric sizes,and by changing the geometric radius and height of a nanopillar unit, the phase of an emergent light beam is randomly adjusted and controlled by the metasurface; when a single curved surface is considered only, calculating out phase distribution phi 0 of incident light passing the curved surface according to a ray tracing method or a finite-different time-domain (FDTD) method, and then calculatingout phase distribution phi d of user-customized functions according to a diffraction theory or a holographic principle analysis method, thereby compensating a phase difference phi p of the two by using the dielectric conformal metasurface; and carrying out coding on the phase of the metasurface. The user-customized functions include lens focusing, adjustable abnormal refraction, optical camouflage and illusion functions. According to the method, the corresponding technical problems in the field of wearable electronic products, medical equipment or photoelectric devices can be solved.

The invention discloses a wide-band RCS reduction super surface based on slit loading, comprising a dielectric substrate, a metal patch for loading a gap and a metal floor. The metal patch loaded witha plurality of pairs of cross-shaped slits is printed on the upper surface of the dielectric substrate, and the metal floor is printed on the lower surface of the dielectric substrate. An artificialmagnetic conductor unit is designed to have a resonant frequency of 12 GHz, and the in-phase reflection relative bandwidth is 50%. At the same time, broadband AMC super units and double-ring AMC superunits are arranged according to a 3*3 chessboard manner at intervals. Each kind of AMC super units consists of 3*3 basic AMC units, and finally RCS reduction of 7.5 dB or more in the frequency rangeof 8 to 19.2 GHz is realized. The artificial magnetic conductor structure and the AMC-AMC checssboard-shaped electromagnetic stealth surface of the invention have the advantages of good robustness, polarization insensitivity and the like.

The invention relates to a metamaterial wave absorber and a design method. The metamaterial wave absorber is characterized by comprising a dielectric plate, a metal plate and a metal material having aperiodic structure, wherein the dielectric plate is used as a substrate of the metamaterial wave absorber and is arranged between the metal plate and the metal material having the periodic structure;the metal material having the periodic structure is composed of multiple unit-cell structures which are periodically and repeatedly arrayed; and each unit-cell structure is composed of four T shapesarrayed symmetrically in a rotatable manner. According to a metamaterial absorbing structure disclosed by the invention, under a specific frequency band, the surface impedance of the structure is perfectly matched with the impedance of a free space; meanwhile, the structure has a polarization insensitivity characteristic, has an extremely high absorption rate under different polar angles and is stable in absorbing peak frequency; and within an extremely wide angle range, the wave absorbing structure is extremely high in absorbing stability for oblique incidence TE and TM polaried electromagnetic waves.

The invention relates to a wideband bidirectional wide-angle absorbing structure comprising a moth-eye nanostructure array. The moth-eye structure has a bottom-width-to-top-width ratio greater than 1to 1. The surface of the moth-eye structure is covered with a metal layer. The moth-eye nanostructure array has a period of 200 to 450 nm, a ratio of height to period greater than 2, and a ratio of width to period greater than 0.5. A preparation method of the broadband bidirectional wide-angle absorbing structure comprises the steps of: obtaining a moth-eye nanostructure on a base material by photoetching or replicating anodic aluminum oxide; and depositing metal on the upper surface of the moth-eye nanostructure by evaporation or magnetron sputtering. The structure effectively absorbs electromagnetic waves input from the upper surface and the lower surface, and realizes ultra-wideband bidirectional high-efficiency absorption (>95%) from the ultraviolet band to the near-infrared band, hasnot only a polarization-insensitive characteristic but also good angular tolerance, and can achieve bidirectional absorption efficiency of 90% in a range of + / - 60-degee angle of incidence. The wideband bidirectional wide-angle absorbing structure is simple in structure, low in preparation cost and convenient in large-scale and batch production.

The invention provides a wave-absorbing and wave-transmitting integrated frequency selective surface with an ultra-wide wave-transmitting band. According to the technical schemes, the wave-absorbing and wave-transmitting integrated frequency selective surface with the ultra-wide wave-transmitting band comprises FSS units which are periodically arranged, wherein all the FSS units are the same. EachFSS unit is of a structure comprising three layers, namely a first layer, a second layer and a third layer; the first layer comprises a dielectric plate (1); a metal patch (2) is arranged in the center of the upper surface of the dielectric plate (1); the metal patch (2) is of an N-arm square spiral structure; metal strips (3) are evenly distributed around the metal patch (2); each metal strip (3) is connected with the metal patch (2) through a resistor (4); the second layer is an air interlayer (5); and the third layer is a wave-transmitting layer (6). With the wave-absorbing and wave-transmitting integrated frequency selective surface with the ultra-wide wave-transmitting band of the invention adopted, an ultra-wideband, high-transmittance and high-angle stability wave-transmitting bandcan be realized, and a wave-absorbing characteristic can be generated outside the wave-transmitting band. In addition, the surface of the invention is simple in structure and easy to machine.

The invention relates to a coupling device comprising a support substrate; a first layer arranged on the support substrate and comprising first patterns produced within the thickness of said first layer, said first patterns being arranged in parallel and periodic rows; a second layer arranged on the first layer and comprising second patterns passing through the thickness of said second layer, said second patterns being arranged in parallel and periodic rows. The direction of periodicity of the rows of the first patterns is perpendicular to the direction of periodicity of the rows of the second patterns. The rows of the first patterns extend over a distance greater than or equal to the wavelength in the void of the optical wave intended to be coupled. The first patterns have a width less than or equal to a tenth of the wavelength of the optical wave intended to be coupled, and the period of these patterns is between 50 nm and 1 μm. The second patterns are arranged so as to form a periodic diffraction grating.

The invention discloses a three-frequency polarization insensitive electromagnetic energy collection structure unit and a collection surface. The collection structure unit comprises four identical-structure rectangular resonance rings having openings at bottom edges, centers of top edges of the rectangular resonance rings are provided with circular through holes, one side edge of each rectangular resonance ring is connected with a bottom edge of the adjacent rectangular resonance ring, and an end-to-end rectangular resonance ring structure is formed. The collection surface comprises a metal structure layer, a medium substrate, a ground metal layer and a matching resistance array, wherein the metal structure layer comprises more than one collection structure unit, the medium substrate is provided with through holes in matching with the circular through holes respectively, the matching resistance array comprises more than one resistor, each resistor is respectively arranged in one through hole, one end of the resistor is connected with an edge of the circular through hole, and the other end is connected with the metal layer. According to the collection structure unit and the collection surface, a purpose that resonance absorption is generated at three frequency bands is realized, polarization insensitive characteristic is realized, the collection structure unit is applicable to application under the complex electromagnetic environment, the structure is stable and solid, cost is low, and the collection structure unit is suitable for large-scale production.

The invention provides a low-band frequency selective surface with minimized cell sizes. The low-band frequency selective surface comprises a printed circuit board (PCB). An upper conductive layer is arranged on the front surface of the PCB, and a lower conductive layer is arranged on the back surface of the PCB. The upper conductive layer consists of upper periodical cells which are periodically arranged. The lower conductive layer consists of lower periodical cells which are periodically arranged. The upper and lower periodical cells are provided with vertically aligned conducting strips which are surface-surface coupled to form high distributed capacitance to reduce the resonance frequency of the frequency selective surface. The more than 20*20 upper periodical cells correspond to the lower periodical cells. According to the frequency selective surface, the vertically aligned conducting strips are arranged in the upper and lower conductive layers, and are surface-surface coupled to form the high distributed capacitance, so that the resonance frequency of the frequency selective surface is remarkably reduced. The frequency selective surface is insensitive to the polarization characteristics of electromagnetic waves, and the passband characteristics of different polarized electromagnetic waves (transverse electric (TE) waves and transverse magnetic (TM) waves) are substantially the same.

The invention discloses an ultra-wide-band fully-polarized stealth random surface and a design method thereof. Each unit structure comprises an upper-layer metal patch layer, a medium substrate and alower-layer continuous metal backboard, which are combined together in sequence. The designed random surface realizes non-directional scattering of electromagnetic waves through the microstrip reflection array antenna theory. The unit structures of the random surface are same in structure, but different in size. An HFSS automatic parametric modeling method is suitable for continuous establishing of such model. In order to realize automatic generation of different sizes of unit structures and get the ordered arrangement, programming design can be carried out through MATLAB software to finish automatic modeling of the random surface. The random surface is small in difficulty of the design principle, has an ultra-wideband low RCS characteristic, and meanwhile, has a polarization insensitive property; and the random surface has the advantages of very low profile, thinner thickness, light weight and easy processing, and can be widely applied to the field of electromagnetic stealth of each device platform and weapon platform and the like.

The invention provides a polarization-independent ultra-narrow multiband tunable perfect absorber, and belongs to the field of metamaterials. The absorber comprises a metal layer, a dielectric layer and a periodic metal nanostructure array layer; the metal layer as a reflection layer is arranged on a bottom layer; the dielectric layer is positioned between the metal layer and the periodic metal nanostructure array layer; and the periodic metal nanostructure array layer is formed by periodically arranging metal cylinders with air holes etched in the middles. According to the absorber, ultra-narrow multiband perfect absorption can be realized, and the perfect absorption is insensitive to polarization state change under normal incident light. The maximum absorption of the absorber reaches 99.9%; the maximum bandwidth does not exceed 30 nm; and the sensing sensitivity reaches 325 nm / RIU.

The invention provides a graphene adjustable dual-band metamaterial absorber. The metamaterial absorber is composed of a plurality of absorber units, each absorber unit is composed of a bottom metal film (1), a middle dielectric layer (2) and a top graphene film (3) which are sequentially arranged from bottom to top, and the bottom metal film (1), the middle dielectric layer (2) and the top graphene film (3) are attached to one another. The bottom metal film (1) is an all-metal film. The top graphene film (3) is patterned single-layer grapheme. The geometric center of the patterned single-layer graphene, the geometric center of the middle dielectric layer (2) and the geometric center of the bottom metal film (1) are on the same straight line. The metamaterial absorber provided by the invention has the characteristics of high absorptivity, tunable frequency, wide incident angle and polarization insensitivity, and has very high engineering application value.

The invention discloses a metamaterial terahertz biosensor and a production method thereof. The metamaterial terahertz biosensor comprises a substrate layer and a dielectric layer. A metal reflectinglayer is arranged on the substrate layer; a metal microstructure layer is arranged on the dielectric layer; a micro-flow channel for a measured liquid to flow through is formed between the metal reflecting layer and the metal microstructure layer; a liquid inlet and a liquid outlet of the micro-flow channel are formed in the substrate layer; and the metal microstructure layer is a periodic structure unit attached to the dielectric layer, the metal microstructure layer is composed of a square metal ring and a double-''H''-shaped crossed metal structure which is arranged in the square metal ringand is concentric with the square metal ring, and the double-''H''-shaped crossed metal structure is composed of two ''H''-shaped metal rings which are completely the same in structure and are vertically crossed. The sensor provided by the invention has an extremely high absorption peak, relatively high sensitivity and polarization insensitivity.

The present invention relates to a microwave band polarization insensitive six-frequency band metamaterial wave absorber. The metamaterial wave absorber is composed of a top resonant element, a medium substrate and a metal bottom plate, the top resonant element and the metal bottom late are attached on the upper and lower surfaces of the medium substrate respectively, the top resonant element is composed of four multimode omega-shaped resonators which are placed at the upper, lower, left and right edges of the medium substrate symmetrically and are totally same, and the multimode omega-shaped resonators can show a plurality of different absorption peaks under the horizontal polarization and the vertical polarization. The metamaterial wave absorber provided by the present invention has the characteristics of high wave absorption rate and insensitive polarization, also has six wave absorption peak points, and has the very high engineering application value.

The invention discloses a double-passband frequency selective surface based on a high-dielectric low-loss all-dielectric metamaterial. The double-passband frequency selective surface comprises two layers of microwave ceramic structures and an air layer clamped between the two layers of microwave ceramic structures. Each microwave ceramic structure is composed of a microwave ceramic substrate of an etched cross-shaped flower-type pore structure and a cylindrical dielectric resonator, wherein the cylindrical dielectric resonator is installed in the center of the cross-shaped flower-type pore structure, and the thickness of the cylindrical dielectric resonator is the same as that of the microwave ceramic substrate. The microwave ceramic substrate is made of high-dielectric low-loss microwave ceramic materials. A pore opening period unit is of a cross-shaped flower-type pore structure, and the band-pass characteristics of the FSS can be expanded and optimized by adjusting the dielectric resonator in the center of the unit structure. By the adoption of the all-dielectric microwave ceramic design, the double-passband frequency selective surface contains no metal materials and has the advantages of being low in loss, high in power capacity, resistant to high temperature and the like; the dual-band gating characteristics within the Ku wave band can be achieved, and the double-passband frequency selective surface has the polarization insensitivity and the good angle stability.

The invention relates to a method for generating a Bessel beam array based on a Huygens' meta-surface, belonging to the technical fields of micro nano optics and binary optics applications. The methodcomprises the following steps: the phase of a Daman grating unit is optimized through a genetic algorithm to realize a uniform-power beam splitting function; the phases of Bessel beams are superimposed to obtain a total phase; a meta-surface is encoded according to the optimized total phase; the phases and amplitudes of outgoing beams are adjusted arbitrarily through the meta-surface by changingthe radius of a disk nanopillar unit; and the phase change of the transmitted light can cover the range from 0 to 2*Pi and the transmittance can be kept over 70% by changing the radius of the nanopillar unit, and a processing file of a corresponding medium meta-surface is generated. A Bessel beam array will be generated in the transmission direction when a sample is irradiated by laser, and the generation result is independent of the incident polarization. The method has the characteristics of long propagation distance and high efficiency.

The invention discloses a multi-wavelength near infrared absorber insensitive to polarization, which belongs to the technical field of near infrared metamaterial absorber, and solves a problem of highabsorption of electromagnetic waves only in one, two or three wavelengths. The absorber consists of a plurality of absorber units. Each absorber unit comprises: a substrate (1), a gold film (2), anda metal nanocavity (21). The gold film (2) is tightly attached to the upper surface of the substrate (1). The metal nanocavity (21) is a cross-shaped groove, is located at the center of the structure,and is etched from the upper surface of the gold film (2) to a certain depth into the gold film (2) but not penetrates the film. The metal nanocavity (21) is filled with electromagnetic wave materials. The near-infrared absorber has the characteristics of simple structure, high absorption rate, polarization insensitive, and wide angle of incidence, and has six absorption peak points.

The invention discloses a high-speed graphene terahertz modulator. According to the modulator, a metamaterial unit is adopted as a basic structure; a graphene transistor is adopted; the on-off of the opening of the metamaterial unit is adjusted and controlled through changing the grid voltage of the graphene transistor; and therefore, high-speed and effective modulation on terahertz waves can be realized. With the high-speed graphene terahertz modulator of the invention adopted, the modulation rate of a traditional metamaterial terahertz modulator can be effectively improved, and high-speed and high efficiency modulation on the terahertz waves can be realized. The high-speed graphene terahertz modulator of the invention can work under room temperature, can be manufactured through adopting existing processing technologies, and can be miniaturized and has high integration degree.

The invention belongs to the technical field of thermal radiation, and particularly relates to a dynamic thermal radiation refrigeration device based on phase change material vanadium dioxide. According to the dynamic thermal radiation refrigeration device based on the phase change material vanadium dioxide, on the basis of the classic metal-medium-metal metasurface structural design, a transition medium layer is introduced to effectively improve the adhesive force of a phase change material vanadium dioxide film; and the whole device is adjusted and controlled to correspond to the peak value of the black body radiance at the room temperature through selection of the medium layer material, and therefore, the technical problem that an existing heat radiation refrigeration device is relatively poor in refrigeration effect is effectively solved. According to the dynamic thermal radiation refrigeration device based on the phase change material vanadium dioxide, when the temperature is higher, energy is radiated outwards through an intermediate infrared 8-14 micron atmosphere window, and sunlight is reflected; when the temperature is lower, energy is hardly radiated outwards, so that the functions of intelligent temperature control and dynamic refrigeration are achieved; the device has the characteristics of intelligent dynamic temperature control, simple structure, convenience in large-area preparation, zero energy consumption, polarization insensitivity and the like; and the device is of great significance in solving the problem of excessive refrigeration and relieving the urban heat island effect, and has application potential in the fields of infrared camouflage and the like.

A fiber optical attenuator utilizing the cut-off phenomenon for single mode propagation of an optical wave down a single mode fiber, comprising an element such as a pixelated liquid crystal element, capable of spatially changing the phase across the cross section of an input optical signal. Such a spatial phase change is equivalent to a change in the mode structure of the propagating wave. The signal propagating in the single mode output fiber is attenuated in accordance with the extent to which higher order modes are mixed into the low order mode originally present. When the mode is completely transformed to higher order modes, the wave is effectively completely blocked from entering the output single-mode fiber, and the attenuation is high. The level of attenuation is determined by the fraction of the wave which is converted to modes other than the lowest order mode, and is thus controllable by the voltage applied to the pixels of the liquid crystal element.

The invention provides a dual-band terahertz wave absorber of a graphene metasurface. The metasurface wave absorber is composed of a plurality of wave absorber units, each wave absorber unit is composed of a bottom-layer metal film (1), a middle dielectric layer (2) and a top-layer graphene film (3) which are sequentially arranged from bottom to top, and the bottom-layer metal film (1), the middledielectric layer (2) and the top-layer graphene film (3) are attached to one another; the bottom-layer metal film (1) is an all-metal film, the top-layer graphene film (3) is patterned single-layer graphene, and the geometric center of the patterned single-layer graphene, the geometric center of the middle dielectric layer (2) and the geometric center of the bottom-layer metal film (1) are on thesame straight line. The metasurface wave absorber has the advantages of high absorptivity, wide incident angle, insensitive polarization and the like.

The invention relates to a coupling device comprising a support substrate; a first layer arranged on the support substrate and comprising first patterns produced within the thickness of said first layer, said first patterns being arranged in parallel and periodic rows; a second layer arranged on the first layer and comprising second patterns passing through the thickness of said second layer, said second patterns being arranged in parallel and periodic rows. The direction of periodicity of the rows of the first patterns is perpendicular to the direction of periodicity of the rows of the second patterns. The rows of the first patterns extend over a distance greater than or equal to the wavelength in the void of the optical wave intended to be coupled. The first patterns have a width less than or equal to a tenth of the wavelength of the optical wave intended to be coupled, and the period of these patterns is between 50 nm and 1 μm. The second patterns are arranged so as to form a periodic diffraction grating.

The invention relates to a light wide-frequency wave-absorbing material based on an impedance metamaterial and a preparation method of the light wide-frequency wave-absorbing material. The preparationmethod comprises the following steps: (1) dispersing carbon nano tube powder into a resin solution to prepare carbon nano tube slurry, and then scraping the carbon nano tube slurry on a polyimide film to obtain a carbon nano tube coating film; (2) etching a periodic structure composed of a plurality of periodic structure units into the carbon nano tube coating film obtained in the step (1) to obtain an impedance metamaterial; and (3) bonding the impedance metamaterial obtained in the step (2) with a low-dielectric film through an adhesive, and then carrying out curing to prepare the light wide-frequency wave-absorbing material. The light wide-frequency wave-absorbing material has excellent wave-absorbing performance in a wave band of 8-18 GHz, the absorbing bandwidth reaches 10 GHz, and the light-weight wide-frequency wave-absorbing material has excellent characteristics of light weight, thin thickness and polarization insensitivity.

The invention discloses a symmetrical terahertz polarization insensitive artificial microstructure. The microstructure is a transmission type hyperbolic surface which is provided with a centrosymmetric split ring structure, and is used for generating various resonant modes. The microstructure comprises a substrate dielectric substrate, and the substrate dielectric substrate is provided with a metal structure, wherein the metal structure is formed by periodically arranging a plurality of cross-shaped metal resonance units, each cross-shaped metal resonance unit comprises a square outer frame and a cross-shaped grating structure, and the cross-shaped grating structure is a cross-shaped grating which is arranged inside the square outer frame and the center of the cross-shaped grating structure is separated. No matter whether the vibration is LC resonance or dipole resonance, the influence of the vibration of the geometric structure on the resonance frequency and the transmission amplitude is very small. Under the excitation of TE and TM, the transmissivity results are consistent, the polarization insensitivity is realized, and the modulation depth of the unpolarized incident light high-speed modulator can be improved. Due to excitation of the high-order resonant mode, the method can be applied to various environments such as high-sensitivity biological detection and narrow-band filtering.

The invention discloses a broadband adjustable terahertz wave absorber based on grapheme. Metal is used as a reflecting substrate, an insulating dielectric layer and a graphene layer are sequentiallyarranged upwards in structure, and the graphene layer is composed of a regular single-layer graphene square sheet structure. Because the graphene shows strong metallicity in infrared and terahertz bands, the graphene structure is directly used as a resonance structure unit, and local surface plasma resonance is combined with surface plasma resonance of the graphene structure to realize the broadband wave absorber with a single-layer structure, so that the processing technology of the structure is greatly simplified. Due to the unique electrical characteristics of the graphene, the chemical potential and the surface conductivity of the graphene can be changed through change of the external bias voltage, so that the broadband strong absorption of incident terahertz waves is adjusted in a wide range. The terahertz wave absorber is simple in structure and high in absorption efficiency, and has important application prospects in the fields of terahertz imaging, spectra, invisibility and thelike.

The invention provides an infrared metamaterial wave absorbing body. The infrared metamaterial wave absorbing body comprises at least four wave absorbing body units arranged in a matrix mode. Each wave absorbing body unit comprises a substrate, a metal layer located right above the substrate, a dielectric layer located right above the metal layer and a cross round ring structure located right above the dielectric layer, wherein the cross round ring structure is attached to the surface of the dielectric layer and formed by crossing a round ring and a cross and then removing the cross part in the round ring, the circle center of the round ring and the geometric center of the cross coincide, and the cross part outside the round ring forms four arms of the cross round ring structure. The lengths of the four arms of the cross round ring structure are the same, the widths of the four arms of the cross round ring structure are the same, the cross sections of the substrate, the metal layer and the dielectric layer are all square, and the arms of the cross round ring structure are parallel with one edge of each square. The infrared metamaterial wave absorbing body is high in absorbing rate, wide in incidence angle and insensitive in polarization, and has good tunability.

The invention relates to the technical field of ultra-high-resolution color filters, in particular to an ultra-high-resolution color filter based on a hydrogenated amorphous silicon metasurface and apreparation method and application thereof. The antenna comprises a transparent substrate, a dielectric metasurface and a transparent covering layer. The dielectric metasurface is hydrogenated amorphous silicon with a nanorod structure and is distributed on the surface of the transparent substrate in an array structure. The transparent covering layer covers the dielectric metasurface to seal the dielectric metasurface in the transparent covering layer. According to the invention, the color filter can work in a transmission mode and a reflection mode at the same time, so that the light utilization efficiency is remarkably improved; and after simple adjustment of the structural parameters of a single sub-wavelength structure in the metasurface, the full-color ultrahigh-resolution color printing can be realized.

The invention discloses a frequency selective surface-based terahertz broadband band-pass filter. The filter comprises a frequency selective surface layer which is of a single layer structure; the outer surface of the frequency selective surface layer is made from a metal material; multiple through holes are formed in the frequency selective surface layer, and arranged in the frequency selective surface layer at equal intervals, a periodic through hole array is formed, and frequency-selecting is conducted on a terahertz wave through coupling of the terahertz wave and the periodic through holearray. The terahertz broadband band-pass filter has the single-layer frequency selective surface structure of a porous structure, the in-band pass rate is high, the structure is simple, and the processing difficulty is greatly lowered; polarized light x and polarized light y have the same band-pass filter property, and the polarization insensitivity is achieved; due to the fact that the size and thickness of a periodic unit are large, laser drilling and other technologies can be adopted for completion, and the processing speed is high.

The invention discloses an ultra-wideband wave-absorbing structure for reducing the RCS of an antenna. The ultra-wideband wave-absorbing structure comprises a surface skin dielectric layer, an impedance matching dielectric layer, an impedance type frequency selective surface, an impedance type frequency selective surface substrate, a dielectric layer and a conductive reflecting layer which are arranged from top to bottom, the impedance type frequency selective surface is composed of N * N conductive units, each conductive unit comprises a conductive outer circular ring and a conductive inner circular ring which are concentrically arranged, and each conductive circular ring is uniformly loaded with four resistors. According to the ultra-wideband wave-absorbing structure for reducing the RCS of the antenna, the resistance loading double circular rings are adopted as the impedance type frequency selective surface, so that the RCS of the antenna can be reduced, the purpose of hiding the antenna is achieved, and the ultra-wideband wave-absorbing structure is stable in performance and has a wide practical application prospect.

The invention relates to a multispectral transparent microwave absorbing material and a preparation method thereof. The multispectral transparent microwave absorbing material comprises an optical window, a surface periodic metal mesh formed in the upper surface of the optical window and a bottom periodic metal mesh formed in the lower surface of the optical window. According to the invention, theupper surface and the lower surface of the window glass of the optical system are respectively plated with a metal mesh with a specific line width and a specific periodic structure by adopting a photoetching process; the optical window material with multispectral transparency and microwave absorption characteristics is formed, the light transmittance of the optical window material in visible lightand infrared frequency spectrums is greater than 80%, an absorption peak exists in a microwave frequency band of 8-18GHz, the minimum value of reflectivity is not greater than-6dB, and the optical window material has polarization insensitivity.