33 results about "Electromagnetic wave polarization" patented technology

The invention relates to an electromagnetic wave polarization conversion system and conversion method based on a non-Hermite metasurface, the conversion system comprises a dual-port model having an x polarization mode and a y polarization mode, and the dual-port model satisfies that the two polarization modes have the same resonant frequency omega0, radiation loss gamma and intrinsic loss gamma, certain coupling strength kappa exists between the two polarization modes, and the resonant frequency omega0, the radiation loss gamma, the intrinsic loss gamma and the coupling strength kappa meet the condition that when x polarized waves / y polarized waves are only emitted to the two sides of the dual-port model, the corresponding emitted x polarized waves / y polarized waves are 0, and the emitted x polarized waves / y polarized waves are 0. Therefore, the dual-port model forms an equivalent PT symmetrical metasurface structure with the maximum linear polarization conversion efficiency. Electromagnetic wave polarization conversion is achieved through the PT symmetric metasurface based on the equivalent gain, materials do not need to have real gain or different losses of oscillators in a structure are not required, and material use and structural design can be simplified.

The invention relates to the technical field of electromagnetic wave polarization conversion, in particular to a transmission and reflection switchable multifunctional polarization converter based on a metasurface, and the polarization converter comprises four layers, namely a TOPAS (cycloolefin copolymer) dielectric layer, a crossed I-shaped metal resonance layer, a silicon dioxide dielectric layer and a metal-VO2 alternating grating layer from top to bottom. According to the design, conversion between a transmission function and a reflection function can be realized by changing the conductivity of vanadium dioxide: 1, in a transmission mode, incident polarized waves can be converted into cross polarized waves with broadband characteristics; and 2, in a reflection mode, incident linearly polarized waves can be converted into left-hand circularly polarized waves in a frequency band of 0.8 THz-1. 83 THz, and the incident linearly polarized waves can be converted into right-hand circularly polarized waves in a frequency band of 2.7 THz-3. 06 THz. According to the invention, the conversion functions are more, cross polarization conversion and linear-circular polarization conversion can be realized, and the engineering applicability is higher.

The invention discloses a broadband polarization angle continuous adjustment antenna based on an electric control metasurface. The broadband polarization angle continuous adjustment antenna comprises a linear polarization slot coupling microstrip antenna and an active electric control metasurface capable of continuously adjusting a linear polarization inclination angle. The linear polarization slot coupling microstrip antenna is a feed source, is excited in a slot coupling mode, and can radiate a single linear polarization wave in a broadband. The active electric control metasurface is composed of electromagnetic units arranged in an array mode, an H-shaped metal strip structure and a diode are integrated in the active electric control metasurface, the on resistance of the active electric control metasurface is adjusted by changing the positive bias voltage of the diode, the amplitude of an orthogonal transmission electric field component is driven to change, and therefore the polarization angle of the antenna is adjusted and controlled. According to the invention, the real-time change of the polarization angle of the electromagnetic wave is realized, the antenna shows good working characteristics in a wide frequency band, the compatibility and the integration degree of the linear polarization antenna can be effectively improved, and the antenna has a good application prospect in the fields of airborne communication, electronic countermeasure, polarization imaging and the like.

The invention belongs to the technical field of polarization conversion metasurfaces, and particularly provides a high-frequency-selectivity reflective polarization conversion metasurface with fourth-order response, which is used for realizing a polarization converter with high polarization conversion rate. The half-wavelength micro-strip resonator is composed of a frequency selective surface (FSS) and a coupling layer, a coupled half-wavelength micro-strip resonator is composed of an L-shaped micro-strip line of a bottom metal layer and a through hole, response is expanded to a high order, the polarization conversion rate is increased, and the broadening bandwidth is increased; meanwhile, the middle metal layer introduces a polarization conversion zero point, thereby improving the frequency selection characteristics of the two sides of a transmission frequency band. Moreover, the polarization metasurface is rotationally symmetrical in structure, has a dual-polarization conversion characteristic, and has a relatively high application value in the aspect of electromagnetic wave polarization conversion.

The present invention discloses a polarization-insensitive electromagnetic rectifying surface, which solves the problems that the efficiency of the rectifying surface is easily affected by the polarization direction of the incident electromagnetic wave, the matching and DC synthesis circuits are complex, and the energy loss is relatively large. The upper surface of the dielectric substrate (2) of the rectifying surface includes m rows and n columns of rectifying surface units (1) with the same size and shape, where m and n are positive integers greater than or equal to 2, and an output filter circuit (4). The lower surface of the dielectric substrate (2) is covered by a metal ground (3), and the lower surface includes pads (14) with metallized vias (13) and Schottky diodes (15); each rectifying surface unit (1) includes 1 energy receiving unit (11), 4 microstrip lines (12), 4 metallized vias (13), 4 pads (14) located on the lower surface, and 4 Schottky diodes (15). The present invention has the advantages of being insensitive to the polarization direction of the incident wave, having a simple structure, and high rectifying efficiency.

A polarization-sensitive array direction-finding method based on the spatial polarization characteristics of antennas belongs to the technical field of array signal processing. The purpose of the present invention is to solve the problem of large errors in DOA and spatial polarization parameter estimation due to the inconsistent representation of antenna and electromagnetic wave polarization in existing methods and the failure to consider the spatial polarization characteristics of receiving antennas. The present invention describes the polarization definition of the transmitting antenna and the receiving antenna, the rotation of the receiving antenna, and the polarization state of the electromagnetic wave in a unified global rectangular coordinate system during the polarization-sensitive array direction-finding process, which can quantitatively describe the polarization of the antenna, making the description of the electromagnetic wave and antenna polarization more natural. At the same time, the direction-finding method of the present invention also considers the influence of the spatial polarization characteristics of the receiving antenna, thereby improving the accuracy of DOA and spatial polarization parameter estimation. The method of the present invention can be applied to polarization-sensitive array direction-finding.

The invention provides a hybrid superstructure applied to low-frequency ultra-wideband electromagnetic isolation. Comprising a low-frequency antenna metal mounting plate, an air and / or medium complementary substrate integrated cascade structure, a sub-wavelength low-frequency electromagnetic wave high-resistance surface cascade structure, a sub-wavelength low-frequency electromagnetic wave polarization converter cascade structure, a low-frequency ultra-wideband metamaterial wave absorber and a low-frequency ultra-wideband transceiving antenna. Through hybrid design of complementary substrate integration, high-resistance surface cascading, polarization converter cascading and a wave absorbing structure, excellent electromagnetic isolation performance is realized in a wide frequency band; the isolation degree between the low-frequency ultra-wideband receiving and transmitting antennas is remarkably improved, and the direction finding precision of the system is improved; the adverse effect of the antenna mounting plate on the radiation characteristic of the antenna is effectively reduced, and the working performance of the antenna is improved; the structure is flexible and adjustable, structural parameters can be optimized according to specific application scenes, and different engineering requirements are met.

The electromagnetic wave polarization imaging fusion enhancement method and system belong to the field of remote sensing and detection technology. The problem that the target and background contrast effect is poor and the image quality is affected in the existing fusion process of different polarization images is solved. The present invention obtains four polarization images of the target detection scene; the four polarization images are: horizontal polarization image, 45-degree linear polarization image, vertical polarization image and 135-degree linear polarization image; according to the polarization angle relationship of the four polarization images, the four polarization images are converted into Stokes' second component TQ image and third component TU image by using the pixel values ​​of the pixel points in the four polarization images; the Stokes' second component TQ image and third component TU image are converted into four regional images; and the mark of each regional image is obtained; using the mark of each regional image, the four regional images are fused to obtain an enhanced image. The present invention is suitable for the fusion enhancement of electromagnetic wave multi-polarization imaging of target detection scenes.

The invention provides a target scattering characteristic characterization method based on an electromagnetic vortex polarization joint scattering matrix, and belongs to the technical field of radar target scattering characteristics. From two dimensions of an electromagnetic wave orbital angular momentum (OAM) and a spin angular momentum (SAM), an electromagnetic vortex polarization combined scattering matrix is established by using an OAM electromagnetic vortex mode orthogonal characteristic and an electromagnetic wave SAM polarization mode orthogonal characteristic at the same time, and target scattering characteristics including all angular momentum characteristics of electromagnetic waves are represented. And target scattering characteristics under irradiation of electromagnetic vortex waves in different modes and different polarization modes are comprehensively described. According to the method, the electromagnetic vortex scattering matrix and the polarization scattering matrix are fused to construct the three-dimensional matrix representing the scattering characteristics of the target, so that multi-dimensional and refined description of the scattering characteristics of the target under complex electromagnetic wave irradiation is realized.

The electromagnetic wave polarization parameter estimation method based on a single antenna is implemented as follows: (1) establish a three-dimensional rectangular coordinate system, and the real signal of the electromagnetic wave incident from any direction in space is represented as E(n); (2) use two adjacent snapshot electric field vectors p1 and p2 to calculate the vector m(n) parallel to the propagation direction of the electromagnetic wave, and take its average value #imgabs0#; (3) estimate the pitch angle θ and azimuth angle φ of the incoming wave based on the components of the vector #imgabs1#; (4) use coordinate transformation to obtain the pitch component E of the electric field θ (n) and the azimuth component E φ (n); (5) Obtain the analytical signals #imgabs2# and #imgabs3# of each component through Hilbert transform (6) Calculate the amplitude E of each component θm (n) and E φm (n), calculate the polarization parameter γ(n); (7) calculate the phase difference Δ(n) between the elevation component and the azimuth component, and estimate the polarization parameter η(n); (8) average the above polarization parameters to obtain the phase descriptor #imgabs4#. The present invention has the advantage of estimating the polarization parameters of electromagnetic waves based on a single antenna, with low cost and small size. The present invention can be applied to fields requiring polarization parameter estimation, such as communications and radar.

The application discloses a method for estimating the elevation angle of a slant ionospheric sounding incoming wave based on polarization response, which comprises the following steps: obtaining the polarization response information of the incoming wave through an orthogonal receiving antenna, so as to determine the limit polarization of the incoming wave signal from the ionosphere into free space, and determining the direction of the incoming wave through the relationship between the limit polarization and the elevation angle of the incoming wave and the geomagnetic field. The method for estimating the elevation angle of the slant ionospheric sounding incoming wave based on polarization response can be applied to the acquisition of the elevation angle information of the incoming wave through the processing and estimation of the polarization information of the electromagnetic wave, and can also be used as an auxiliary means of the traditional short-wave direction finding method.

The invention discloses a metasurface antenna for realizing complete polarization and all-phase modulation, which belongs to the technical field of electromagnetics, and comprises at least one metasurface unit, the metasurface unit comprises a metasurface layer, a dielectric substrate, a metal grounding layer and a metal via hole, the metasurface layer comprises a circular metal patch and a pair of arc-shaped openings which are symmetrical about the center of the patch, a metal via hole penetrates through the dielectric substrate and serves as a rotating center shaft of the metasurface layer, and continuous regulation and control of electromagnetic wave polarization components are achieved by rotating azimuth angles of the arc-shaped openings; and the whole metasurface layer is rotated around the metal through holes, so that global regulation and control of the radiation electromagnetic wave phase are realized. Full-polarization continuous regulation and control and all-phase global coverage are achieved, the system integration degree is greatly improved through ultra-low profile integration, and the large-scale application potential is achieved.

The present invention relates to a broadband reflective electromagnetic wave polarization converter based on a B-shaped metasurface, comprising a plurality of metasurface structural units periodically arranged in the same plane, each of which is composed of a surface metal resonant structure, an intermediate dielectric substrate and a bottom metal backplane. The surface metal resonant structure is similar to a B-shape, that is, it is composed of two metal semicircular rings with the same structural parameters plus a metal strip; the two metal semicircular rings are arranged side by side and there is an overlapping part between the rings; the entire surface metal resonant structure is rotated 45 degrees counterclockwise relative to the vertical direction. The polarization converter can generate cross-polarized waves through reflection of vertically incident linearly polarized electromagnetic waves, and the working bandwidth with a cross-polarization reflectivity greater than 0.9 can reach about 11 GHz. In the frequency range of 8.46~19.61 GHz, the polarization conversion rate of the polarization converter is as low as about 92%, achieving efficient polarization conversion.

This invention discloses a Ku-band wave-to-wave conversion structure, relating to the fields of millimeter-wave communication and radar technology. The Ku-band wave-to-wave conversion structure comprises a three-layer planar structure based on PCB / LTCC technology. The top layer is a graded dielectric substrate, the dielectric constant of which is gradually varied by a doping concentration gradient. The middle layer is a metal microstrip line array, with the linewidth and spacing continuously varying along the propagation direction. The bottom layer is a copper foil grounding layer. The Ku-band wave-to-wave conversion structure provided by this invention is used to achieve efficient conversion of electromagnetic wave polarization modes over a wide frequency band.

The present invention relates to a reconfigurable reflective polarization converter, and more particularly, to a temperature-voltage-controlled reconfigurable reflective polarization converter. The converter comprises a bottom metal reflector, an intermediate dielectric layer, and a top resonant unit layer, arranged sequentially from bottom to top. The top resonant unit layer comprises a plurality of square metal sheets, which are periodically arranged in an M×N pattern on the intermediate dielectric layer to form a periodic array. A phase-change material is coated between adjacent square metal sheets; the phase-change material is VO2 nanopowder dispersed in a PVP matrix. The present invention enables temperature and voltage control of the converter's operating state, is insensitive to the polarization and angle of incidence of the incident electromagnetic wave, exhibits strong adjustability and frequency flexibility, and has the potential to be easily expanded to the terahertz and even optical bands. The converter also features a simple manufacturing process and has significant application value in fields such as antenna radiation and radar cross-section reduction for dynamic electromagnetic wave control.

The present invention discloses an ultra-thin broadband reconfigurable transmission unit and its array, comprising a first metal layer, a second metal layer, and a dielectric layer, with the dielectric layer disposed between the first and second metal layers. The first metal layer includes a radiating patch etched with a π-shaped slot, and a radio frequency switch disposed on the π-shaped slot. The radio frequency switch is reversed to change the state of electromagnetic waves radiated by the radiating patch. The second metal layer includes a receiving patch etched with an L-shaped slot. The first metal layer is connected to the second metal layer via a metal column. The first and second metal layers form a polarization rotation structure such that the polarization of the electromagnetic waves radiated by the first metal layer is perpendicular to the polarization of the electromagnetic waves received by the second metal layer. The reconfigurable transmission unit can be formed by using these two metal layers, the first and second metal layers. The structure is simple and easy to process, which helps to simplify design and reduce costs. The unit can be widely used in the field of antenna technology.

The present invention provides a carrier for circular polarization testing of a dihedral angle structure, which is applied to the technical field of electromagnetic wave polarization testing. The carrier is an integrally formed structure. The carrier has a support surface, and a fixing part for supporting the dihedral angle structure is arranged on the support surface. The included angle between the dihedral angle structure located on the support surface and the horizontal plane is 45°. The carrier for circular polarization testing of the dihedral angle structure provided by the present invention can improve the support stability of the dihedral angle structure and ensure the accuracy of the RCS characteristic measurement of the dihedral angle structure.

The invention discloses an electromagnetic wave reflection or transmission metasurface of a non-uniform metal grid structure and a design method. The metasurface comprises a metal grid layer; the metal grid layer is of a non-uniform metal grid structure, and the non-uniform metal grid changes the polarization conversion ratio by adjusting the density ratio of grid lines in different directions, so that polarization conversion is conducted on reflected waves or transmitted waves while electromagnetic shielding is achieved. The problem that a traditional uniform metal grid metasurface can only achieve the single function of electromagnetic shielding or hiding is solved, and better camouflage, hiding or other effects can be achieved through polarization conversion of reflected waves or transmitted waves while electromagnetic shielding is conducted; the method can be applied to the fields of regulation and control of electromagnetic wave polarization characteristics and stealth of radar radomes, and can also be applied to equipment such as metasurfaces and antennas for polarization conversion regulation.

The present invention relates to a metasurface electromagnetic wave polarization modulator based on a quasi - cross shape, which is composed of multiple polarization units arranged periodically in the same plane. It can achieve cross - polarization reflection of perpendicularly incident linearly polarized electromagnetic waves and belongs to the field of metasurface electromagnetic wave polarization state regulation. The feature of the present invention is that each polarization unit includes a metal layer at the bottom, a dielectric substrate in the middle, and a metal structure unit on the surface. The metal structure unit as a whole is in a quasi - "cross" shape, obtained by deforming the Chinese character "cross", and is an axially symmetric figure placed obliquely. The dielectric and metal materials used in the present invention are conventional materials, and within a certain frequency range, they can achieve polarization regulation of perpendicularly incident linearly polarized electromagnetic waves, with the advantages of being ultra - thin and easy to integrate, making up for the deficiencies of electromagnetic wave polarization modulators based on traditional materials.

The invention relates to the technical field of electromagnetic wave regulation and control, and provides a depth-adjustable quasi-continuous domain bound state electromagnetic wave polarization controller based on multiple defects, and the electromagnetic wave polarization controller sequentially overlaps a substrate and a chiral sub-wavelength structure unit array with the refractive index lower than that of the substrate; the chiral sub-wavelength structure unit array is composed of a plurality of dielectric structure units, a main body of each dielectric structure unit is a rectangular block, a cubic chiral cavity is formed in each of the opposite angles of the upper top surface of the rectangular block, and the upper top surfaces of the chiral cavities are flush with the upper top surface of the rectangular block; the ratio of the height of the chiral cavity to the total height of the dielectric structure unit is 1 / 4-1; cubic positions and shapes of the chiral cavities of the dielectric structural units in the chiral sub-wavelength structural unit array are periodically repeated. The device has the capability of converting incident circularly polarized light into opposite chiral circularly polarized light, and particularly, the circular dichroism intensity and conversion efficiency of the device are superior to those of an existing achiral or simple symmetric broken quasi-continuous domain bound state structure.

The invention relates to a detection device (16) for detecting objects in at least one monitoring area, a road condition detection system, a driver assistance system, a vehicle, and a method for detecting at least one property of an object. The detection device (16) comprises at least one receiving device (24) designed for receiving electromagnetic receiving waves (34) and converting received electromagnetic receiving waves (34) into processable receiving signals (46). The at least one receiving device (24) comprises at least one receiving unit (40) for receiving electromagnetic receiving waves (34) and at least one polarization filter unit (38) oriented in the direction of propagation (X). rThe electromagnetic received waves (34) are arranged in front of at least one receiving unit (40). The at least one polarization filter unit (38) is configured to define four different transmission polarization directions (50) for the electromagnetic received waves (34). The at least one receiving device (24) is configured to convert polarization components of the electromagnetic received waves (34) with four different polarization directions (50) separately into respective received signals (46). The detection device (16) comprises at least one evaluation device (28), which includes means for analyzing the polarization of the electromagnetic received waves (34) based on the received signals (46) of the polarization components with the four different polarization directions (50).

The application provides a conformal protective cover based on a gradient metasurface, which comprises a protective layer, a first phase gradient metasurface layer, a first dielectric layer, a second phase gradient metasurface layer and a second dielectric layer; the first phase gradient metasurface layer is sandwiched between the protective layer and the first dielectric layer; the second phase gradient metasurface layer is sandwiched between the first dielectric layer and the second dielectric layer. The profile of the protective cover is a hexagon, wherein the first layer of phase gradient metasurface is conformal to the circular arc-shaped protective layer, and the second layer of phase gradient metasurface is arranged between the circular arc-shaped first dielectric layer and the second dielectric layer. The phase gradient metasurface is composed of a plurality of phase gradient metasurface units arranged periodically, and each phase gradient metasurface unit comprises a square patch and a Jerusalem cross structure. The application is transparent to electromagnetic waves in a communication frequency band, and is stealthy outside the communication frequency band, and has the advantages of being insensitive to electromagnetic wave polarization, simple overall structure, light weight and easy processing.

This application relates to a discrete and structural encoding method for an electromagnetic metasurface with irregular triangular meshes. The method includes: performing unstructured triangular mesh division on the electromagnetic metasurface to be designed using a mesh division algorithm and extracting all triangular meshes; clustering all triangular meshes to obtain multiple common edges; designing a binary vector, encoding the common edges according to the binary vector, and determining the filling media of the triangular meshes on both sides of the common edge according to the encoded values; when there are encoding conflicts in the filling media of the triangular meshes, using an OR logical relationship for constraint integration; designing a multi-valued vector to encode the loading devices on the triangular meshes on both sides of the common edge, and regulating the encoded values of the loading devices according to the encoding of the common edge, and combining the two to achieve comprehensive structural encoding of the electromagnetic metasurface to be designed. Using this method, the design flexibility is high, the encoding form is concise and efficient, and the simulation effect on complex structures is better, which can improve the ability to characterize and regulate the polarization characteristics of electromagnetic waves.

This application belongs to the field of microstrip antenna technology and relates to a microstrip dipole antenna array for omnidirectional and precise sensing of electromagnetic wave polarization, comprising: two antenna units; the antenna units comprising: a patch layer, a dielectric layer, and a coaxial feed structure; the patch layer comprising: two patches, one located at the top and one located at the bottom of the dielectric layer; the two patches are oriented in opposite directions to form a dipole; the inner conductor and the outer conductor of the coaxial feed structure are connected to the two patches, respectively; the dipoles of the two antenna units are oriented perpendicularly to each other, forming a microstrip dipole antenna array to achieve omnidirectional and precise sensing of electromagnetic wave polarization; and further comprising: two other antenna units; the four antenna units are located in four quadrants, and the dipoles of two adjacent antenna units are oriented perpendicularly to each other. The present application can achieve precise sensing of electromagnetic wave polarization in all directions, and is a two-dimensional structure that is easily integrated with the surface of an object.

The present invention discloses a broadband polarization angle continuously adjustable antenna based on an active electromagnetic metasurface, which includes a linearly polarized slot-coupled microstrip antenna and an active electromagnetic metasurface capable of continuously adjusting the linear polarization inclination angle. The linearly polarized slot-coupled microstrip antenna is a feed source, which is excited by the slot-coupling method and can radiate a single linearly polarized wave within a wide frequency band. The active electromagnetic metasurface is composed of electromagnetic units arranged in an array, and an H-shaped metal strip structure and diodes are integrated inside. By changing the forward bias voltage of the diodes, the on-resistance is adjusted, driving the amplitude of the orthogonal transmitted electric field components to change, thereby realizing the polarization angle control of the antenna. The present invention realizes the real-time change of the polarization angle of electromagnetic waves. The antenna exhibits good working characteristics within a wide frequency band, can effectively improve the compatibility and integration of linearly polarized antennas, and has good application prospects in the fields of airborne communication, electronic countermeasure, polarization imaging, etc.

The present invention relates to the technical field of electromagnetic wave polarization conversion, and specifically proposes a multifunctional polarization converter based on metasurface transflective switchable polarization. The polarization converter comprises four layers, which are, from top to bottom, a cyclic olefin copolymer (TOPAS) dielectric layer, a crossed I-shaped metal resonant layer, a silicon dioxide dielectric layer, and a metal-VO2 alternating grating layer. The design can achieve the conversion of transmission and reflection functions by changing the electrical conductivity of vanadium dioxide: 1. In transmission mode, the incident polarized wave can be converted into a cross-polarized wave with broadband characteristics; 2. In reflection mode, the incident linearly polarized wave can be converted into a left-handed circularly polarized wave in the 0.8THz-1.83THz frequency band, and into a right-handed circularly polarized wave in the 2.7THz-3.06THz frequency band. The present invention has more conversion functions, can realize cross-polarization conversion and linear-circular polarization conversion, and has stronger engineering applicability.

The present application relates to a kind of electromagnetic wave polarization conversion system and conversion method based on non-hermitian super surface, the conversion system includes the double-port model with x polarization mode and y polarization mode, the double-port model satisfies two polarization modes have same resonance frequency ω0, radiation loss γ and intrinsic loss Γ, there is certain coupling strength κ between two polarization modes, and the size of the resonance frequency ω0, radiation loss γ, intrinsic loss Γ and coupling strength κ satisfy when only x polarized wave / y polarized wave is emitted to the double-side of the double-port model, corresponding exit x polarized wave / y polarized wave is 0, to make the double-port model form equivalent PT symmetric super surface structure with maximum linear polarization conversion efficiency.The present application realizes electromagnetic wave polarization conversion using PT symmetric super surface based on equivalent gain, without material having real gain or requiring the loss of structure oscillator to be different, can simplify material use and structure design.

The present invention relates to a terahertz multifunctional metasurface device based on graphene and vanadium dioxide, comprising a top VO2 structural layer, a first polyimide dielectric layer, a VO2 thin film layer, a first metal structural layer, a second polyimide dielectric layer, a graphene structural layer, a silicon dioxide layer, a third polyimide dielectric layer, and a second metal structural layer, arranged sequentially from top to bottom. The present invention enables dynamic switching of transmission-type linear-circular polarization conversion, reflection-type cross-polarization conversion, and broadband absorber functions within the same structure, enabling transmission / reflection mode switching. The bandwidth of the transmission-type linear-circular polarization converter and the reflection-type cross-polarization converter can be dynamically adjusted by changing the graphene's Fermi level. Both the broadband absorber and the reflection-type cross-polarization converter can act on incident LP waves and CP waves, demonstrating the metasurface's sensitivity to the polarization of incident electromagnetic waves.

The present invention discloses a multi-dimensional controllable digital coding metasurface, including M×M metasurface units, wherein the metasurface units include an upper dielectric substrate, a metal floor, a middle dielectric substrate, an upper reflective baffle, a lower dielectric substrate and a lower reflective baffle, a metal patch with parasitic branches is etched on the upper dielectric substrate, a PIN diode is arranged on the metal patch, an upper reflective baffle and a lower reflective baffle are arranged on the upper and lower surfaces of the lower dielectric substrate respectively, and a DC feed network is arranged on the lower surface of the middle dielectric substrate and the lower dielectric substrate; each group of metasurface units is connected by a DC feeder and connected to a single-chip control system, and the mutual conversion of electromagnetic wave polarization is realized by switching the bias voltage on the PIN diode. The metasurface has a strong control function for electromagnetic waves incident perpendicular to the surface, and the state arrangement of the metasurface array units is controlled in real time by an external circuit, so as to realize the functions of abnormal reflection, radar cross section reduction and polarization rotation.

The utility model belongs to the field of teaching appliances, and discloses an electromagnetic wave polarization characteristic demonstration device for teaching, which comprises a support device used for supporting and displaying, and a translation device arranged in the middle of the support device and used for simulating electromagnetic wave motion, and the translation device is in sliding connection with the support device; the translation device comprises a sliding rod, a handle is installed at one end of the sliding rod, a plurality of fixing holes are evenly distributed in the sliding rod, and simulation rods are installed in the fixing holes. According to the electromagnetic wave polarization characteristic demonstration device for teaching, electromagnetic wave polarization is concrete into the arrangement of the simulation rod, so that the intuition of electromagnetic wave polarization is enhanced; when the simulation rods move and pass through the fixing plate, the arrangement of the position pointed by each simulation rod is recorded one by one, whether the polarization characteristic of electromagnetic waves is linear polarization or circular polarization and the space-time rotation direction relation of the circular polarization electromagnetic waves are visually displayed, and students can conveniently observe, understand and memorize.