Electromagnetic transponder

Abstract

The application provides an electromagnetic transmittance enhancer, and belongs to the technical field of microwave frequency electromagnetic wave regulation and control, comprising a plurality of super units arranged in a rectangular shape. Each super unit comprises a dielectric base, a dielectric substrate and a metal patch, the dielectric substrate is vertically arranged at the middle position on the top of the dielectric base; the metal patch is in an inverted L shape and is arranged on one side of the dielectric substrate; when the electromagnetic wave in the air is incident on the upper surface of the electromagnetic transmittance enhancer, the plurality of super units will simultaneously resonate, the electric field component of the transmitted electromagnetic wave will excite electric dipoles of different lengths in the horizontal and vertical directions of the metal patch, and the electric dipoles will interfere with the incident electromagnetic wave to cancel each other out, so that the resonance zero point of the synthesized dipoles points to the direction of the reflected wave, and the electromagnetic wave is transmitted forward from the gap channel between adjacent units. The electromagnetic transmittance enhancer provided by the application can improve the transmittance of electromagnetic wave transmission to the medium under a large incident angle.

Description

Technical Field

[0001] This invention belongs to the field of microwave frequency electromagnetic wave modulation technology, and specifically relates to an electromagnetic anti-reflection device. Background Technology

[0002] Electromagnetic antireflection, also known as electromagnetic anti-reflection, refers to reducing or eliminating reflected waves when electromagnetic waves pass through the interface between different media, thereby increasing transmittance. Due to its high transmission efficiency, it is used as a solution to reduce energy transmission loss. The low insertion loss and wide operating angle of electromagnetic antireflection make it a promising candidate for applications in radar detection, satellite communication, and SAR imaging, greatly promoting the development of electromagnetic antireflection devices. Single-layer and multi-layer antireflection films and frequency-selective surfaces are currently the main methods for achieving electromagnetic antireflection. However, both single-layer and multi-layer antireflection films are limited by the finite material systems available in nature. In particular, the composite of multi-layer films undoubtedly increases the weight and volume of electromagnetic devices, hindering practical production and application. Although frequency-selective surfaces possess wide-band in-band and out-of-band filtering characteristics, the transmittance of electromagnetic waves decreases significantly with increasing incident angle, becoming a bottleneck restricting their development.

[0003] The Brewster effect refers to the phenomenon where, when a specific polarized electromagnetic wave is incident on a dielectric interface at a specific angle, the reflected wave disappears and the entire electromagnetic wave is transmitted. This provides a new way to improve the transmittance of electromagnetic waves. However, the dielectric constant of traditional dielectric materials is usually distributed between three and ten. When the incident angle increases to a grazing incident angle, the transmission efficiency decreases for both transverse electric and transverse magnetic waves, despite the Brewster effect existing for transverse magnetic waves.

[0004] Metamaterials are artificial composite structures or materials composed of subwavelength structural units as basic units, possessing extraordinary physical properties not found in naturally occurring materials. Unlike natural materials, the basic unit structure constituting metamaterials determines their extraordinary electromagnetic, mechanical, and acoustic physical properties, and correspondingly, equivalent extraordinary electromagnetic, mechanical, or acoustic parameters can be obtained. For electromagnetic metamaterials, by adjusting the structural parameters of their artificial structural units, the electromagnetic parameters of the metamaterial can be freely designed, thereby enabling free control over the propagation direction and polarization of electromagnetic waves propagating within them. Compared to traditional materials, metamaterials have extremely high research value in electromagnetic anti-reflection due to their unique electromagnetic properties. The artificial Brewster effect refers to the Brewster effect produced by artificially designed electromagnetic media or structures. With the help of metamaterials, various equivalent electromagnetic parameters of the medium can be realized, and some novel artificial Brewster effects are attracting attention from the academic and engineering communities, and have been measured and characterized experimentally. Recently, Brewster effect under specific polarization and angle has been realized based on a double-layer open resonant ring array, a one-dimensional subwavelength metal grating, and an anisotropic structure of double-ring patches, and used to improve the transmission efficiency of electromagnetic waves.

[0005] While existing work can produce electromagnetic anti-reflection or modulate the Brewster effect, improving the amplitude and bandwidth at large incident angles remains an academic challenge. In particular, work on realizing the Brewster effect and improving transmission efficiency in the microwave band has enormous potential in modern communications and imaging fields and deserves further research and exploration. Summary of the Invention

[0006] To overcome the shortcomings of the existing technology, the present invention provides an electromagnetic anti-reflection device.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An electromagnetic antireflector includes multiple supercells arranged in a rectangular pattern, each supercell comprising:

[0009] Dielectric substrate;

[0010] A dielectric substrate is vertically disposed on top of the dielectric base;

[0011] A metal patch, in an inverted "L" shape, is disposed on one side of the dielectric substrate;

[0012] Electromagnetic waves in the air are incident on the upper surface of the electromagnetic transmissive device, causing multiple supercells to resonate simultaneously. The electric field component of the transmitted electromagnetic wave excites electric dipoles of different lengths in the horizontal and vertical directions of the metal patch, which interfere with and cancel out the incident electromagnetic wave, so that the resonant zero point of the synthesized dipole points to the direction of the reflected wave. The electromagnetic wave is transmitted forward from the gap channel between adjacent supercells.

[0013] Preferably, the dielectric substrate is located at the middle position on top of the dielectric substrate.

[0014] Preferably, the metal patch is etched on one side of the dielectric substrate, and its material is copper with a thickness of 20 μm.

[0015] Preferably, the metal patch includes a horizontal arm and a vertical arm, one end of the horizontal arm is connected to the lower end of the vertical arm, and the length of the horizontal arm is greater than the length of the vertical arm.

[0016] Preferably, the distance between the lower end of the horizontal arm and the top of the dielectric substrate is equal to the distance between the end face of the vertical arm away from the horizontal arm and the end face of the dielectric substrate on the same side.

[0017] Preferably, the width of both the horizontal arm and the vertical arm is 0.6 mm.

[0018] Preferably, the dielectric substrate and the dielectric base plate are both made of resin-based composite material, model FSD338N, and the thicknesses of the dielectric substrate and the dielectric base plate are 3mm and 0.6mm, respectively.

[0019] Preferably, the dielectric constant and loss of the dielectric substrate are 4.3 and 0.025, respectively, and the dielectric constant and loss of the dielectric substrate are 2.65 and 0.001, respectively.

[0020] Preferably, the electromagnetic antireflector operates in the X-band, has an effective angular range of 70°-80°, and measures 590.4mm × 300mm.

[0021] The electromagnetic anti-reflective agent provided by this invention has the following beneficial effects:

[0022] The electromagnetic transmittance enhancer provided by this invention can utilize the artificial Brewster effect. By loading and etching an "L"-shaped metal patch onto a dielectric substrate, and taking advantage of the radiation null point of the electric dipole at a large incident angle, the transmittance of electromagnetic waves to the dielectric at a large incident angle is greatly improved, and it has broadband and wide-angle domain characteristics. Attached Figure Description

[0023] To more clearly illustrate the embodiments and design schemes of the present invention, the accompanying drawings required for this embodiment will be briefly described below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the basic structure of the electromagnetic anti-reflection device provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of a supercell provided in an embodiment of the present invention;

[0026] Figure 3 The super-element equivalent electric dipole vector synthesis and control mechanism provided in the embodiments of the present invention;

[0027] Figure 4 Simulation results of the transmission amplitude of the electromagnetic anti-reflection device provided in the embodiments of the present invention and a pure dielectric substrate of the same size used for comparison;

[0028] Figure 5 The surface current and energy flow distribution of the supercell provided in the embodiments of the present invention;

[0029] Figure 6 Sample photos and actual testing environment provided for embodiments of the present invention;

[0030] Figure 7 The transmission amplitude test results of the electromagnetic anti-reflection device provided in the embodiments of the present invention.

[0031] Figure label:

[0032] 1-Dielectric substrate; 2-Dielectric substrate; 3-Metal patch. Detailed Implementation

[0033] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "connected" or "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, which will not be elaborated further here.

[0036] Example 1

[0037] This invention provides an electromagnetic anti-reflection device, comprising multiple super-units arranged in a rectangular pattern, such as... Figure 1 As shown. Each supercell includes a dielectric substrate 1, a dielectric base plate 2, and a metal patch 3. The dielectric base plate 2 is vertically disposed at the top center of the dielectric substrate 1; the metal patch 3 is in an inverted "L" shape and is disposed on one side of the dielectric base plate 2, as shown. Figure 2 As shown, when electromagnetic waves in the air are incident on the upper surface of the electromagnetic transmissive device, multiple supercells will resonate simultaneously. The electric field component of the transmitted electromagnetic wave excites electric dipoles of different lengths in the horizontal and vertical directions of the metal patch 3, which interfere with and cancel out the incident electromagnetic wave, so that the resonance zero point of the synthesized dipole points to the direction of the reflected wave, and the electromagnetic wave is transmitted forward from the gap channel between adjacent supercells.

[0038] In this embodiment, both the dielectric substrate 1 and the dielectric substrate 2 are made of resin-based composite material, model FSD338N. The thicknesses of the dielectric substrate 1 and the dielectric substrate 2 are 3mm and 0.6mm, respectively. The dielectric constant and loss of the dielectric substrate 1 are 4.3 and 0.025, respectively. The dielectric constant and loss of the dielectric substrate 2 are 2.65 and 0.001, respectively.

[0039] Furthermore, a metal patch 3 is etched on one side of the dielectric substrate 2. The patch is made of copper and has a thickness of 20 μm. The metal patch 3 includes a horizontal arm and a vertical arm. One end of the horizontal arm is connected to the lower end of the vertical arm. The length of the horizontal arm is greater than the length of the vertical arm. The width of both the horizontal and vertical arms is e = 0.6 mm. The distance between the lower end of the horizontal arm and the top of the dielectric substrate 1 is equal to the distance between the end face of the vertical arm away from the horizontal arm and the end face of the dielectric substrate 2 on the same side, both being 0.5 mm.

[0040] The electromagnetic antireflective converter provided by this invention operates in the X-band, with an effective angular domain of [70°, 80°]. Its overall dimensions are 1188mm × 478.5mm, and it is composed of 72 supercells arranged periodically along the x-axis and 50 along the y-axis. The geometric parameters of the supercells in this embodiment are obtained after multiple simulations and optimizations. Specifically, the width and thickness of the dielectric substrate 1 are f = 6mm and t = 3mm, respectively. The length of the dielectric substrate 2 is the same as that of the dielectric substrate 1 (along the x-axis), both being a = 8.2mm. The width of the vertical and horizontal arms of the metal patch 3 is the same as the thickness of the dielectric substrate 2, i.e., e = s = 0.6mm. The lengths of the vertical and horizontal arms of the metal patch 3 are different, being d = 7mm and c = 3mm, respectively.

[0041] Example 2:

[0042] To accurately explain the formation and working mechanism of the Brewster effect in metamaterials, including the electromagnetic energy transfer characteristics, the following explanation combines the derivation of the expression for electric dipole synthesis and simulation analysis results.

[0043] like Figure 3 As shown in (a), the incident angle is θ. i A TM-polarized wave is incident from free space onto a subwavelength metal patch model 3. In a plane parallel to the incident plane, the electric field vector E of this polarized wave exists in both the horizontal and vertical directions. i The generated components are as follows: free electrons on the OP segment metal surface are driven by the horizontal electric field component to form surface charge density waves, while free electrons on the QP segment metal surface are driven by the vertical electric field component to form surface charge density waves. Therefore, by synthesizing the surface charge density waves from these two directions, a surface charge density wave with a certain tilt angle θ can be obtained. g Surface charge density wave.

[0044] like Figure 3 As shown in (b), the following stipulations are made: the length of the OP segment is l1, and the length of the QP segment is l2.

[0045] Since the electromagnetic environment sensed by the OP segment metal consists of air, dielectric substrate 2, and dielectric base 1, the equivalent dielectric constant it senses should be among these three, i.e., 1 < ε1 < 4.3. Therefore, the actual electrical length of l1 should be its sensed equivalent refractive index multiplied by its geometric length, i.e.

[0046] The electromagnetic environment sensed by the metal in segment QP is air and dielectric substrate 2. The equivalent dielectric constant it senses should be between these two, i.e., 1 < ε² < 2.65. Similarly, it can be concluded that...

[0047] like Figure 3 As shown in (b) Ⅱ, electric dipoles in the horizontal and vertical directions can be coupled into a single dipole with an angle of θ. g The electric dipole is Where e / / e ⊥ They are respectively horizontal and vertical directions and At this point, if θ can be achieved g =θ s That is, the direction of the synthesized dipole is exactly the direction of the reflected wave. From the perspective of standing waves, if the synthesized electric length is exactly equal to half of the optical path, a standing wave will be formed and resonance will be caused. Then the electromagnetic energy of the incident wave will be concentrated on the anti-reflection structure model, compressed and transmitted through the gap between the two metal patches 3.

[0048] The transmission amplitude of the large incident angle electromagnetic antireflection device and a pure dielectric substrate 2 of the same size used for comparison were simulated using CST Microwave Studio simulation software. A single supercell was selected as the simulation subject, where the boundary conditions in the x and y directions were set as periodic boundary conditions, and the boundary in the z direction was set as an open boundary. Figure 4 As shown, considering only the dielectric substrate 1, its Brewster angle can be calculated using the formula to be approximately 64°. Figure 4 (a) shows its transmission curve at 64°; however, due to the high loss of the medium itself, the ideal transmission effect was not achieved. Subsequently, the incident angle was further increased, and the results are as follows... Figure 4 As shown in (b), (c), and (d), it can be seen that the anti-reflection effect is improved under the following conditions: 8 GHz, 70° incident angle; 9.7 GHz, 75° incident angle; and 10.5 GHz, 80° incident angle, thus achieving an artificial Brewster effect. Furthermore, from... Figure 4(d) It can be seen that for the dielectric substrate 1 loaded with metamaterial antireflection layer, its average transmission performance is improved by 1.8dB in the 9-11GHz range, the average insertion loss is less than 0.15dB, and the transmittance can reach more than 85%, especially at 10.5GHz, the transmittance reaches 96%. This is attributed to the Brewster effect introduced by the skewed electric dipole, that is, the incident wave on the air side interface will interfere and cancel out the radiation wave of the dipole.

[0049] The following section further analyzes the resonance effect based on the simulated metal surface current distribution and energy flow transport, such as... Figure 5 As shown in (a), the simulation yields the surface current and energy flow distribution under the conditions of an incident angle of 80° and a frequency of 10.5 GHz. First, when the incident wave is incident on the metamaterial structural unit, its electric field component drives the movement of electrons on the metal surface to form a current. Finally, a tilted surface current is obtained through synthesis, which is the direction of the zero-point radiation of the tilted electric dipole. At this time, the non-reflected wave is radiated from this direction, resulting in the artificial Brewster effect; Figure 5 As shown in (b), the supercell energy flow distribution under the same simulation conditions is further monitored. When the artificially constructed Brewster effect is generated, the energy will be confined to the edge of the metal patch 3 and transmitted forward through the gap channel between the two metal patches 3. That is to say, there will be no energy transmission in the direction of the reflected wave. Therefore, the electromagnetic wave incident on the structural unit will undergo almost complete transmission.

[0050] In this embodiment, a metal patch 3 is printed on a 0.6mm thick dielectric substrate 2 using printed circuit board technology, such as... Figure 6 As shown in (a), a vertically oriented dielectric substrate 2 is assembled to create a two-dimensional "grid" structure, ensuring sufficient mechanical strength. Simultaneously, another dielectric substrate 1 with a thickness of 3 mm is fabricated. For the control experiment, dielectric substrates 1 of the same size are used, both with and without the copper-clad dielectric substrate 2. The experimental testing platform is built using a microwave anechoic chamber, surrounded by absorbing materials to eliminate unnecessary electromagnetic wave interference with the measurement results. Figure 6 As shown in (b), the test platform is based on an Agilent E8363B vector network analyzer and a pair of horn antennas that operate in the X-band. The test sample is placed on a turntable.

[0051] like Figure 7As shown, in this embodiment, consistent with the simulation results, dielectric substrate 1 with and without copper-clad dielectric substrate 2 were selected as controls under incident angles of 65°, 70°, 75° and 80°. Compared with the pure dielectric board, although the transmission effect of copper-clad dielectric substrate 2 is poor near Brewster's angle of dielectric substrate 1 itself, the electromagnetic wave transmittance of the overall structure gradually increases as the incident angle gradually increases. Especially at 80° incident angle, the electromagnetic wave has a good transmission effect in the entire X-band, and the average insertion loss is less than -1dB.

[0052] In summary, the electromagnetic anti-reflection device of the present invention has the following beneficial effects:

[0053] 1. The electromagnetic anti-reflection device provided by this invention can achieve the artificial Brewster effect at large incident angles, with a wide angular range and significant gain improvement.

[0054] 2. The electromagnetic anti-reflection device provided by the present invention can improve the transmittance of electromagnetic waves when they are transmitted to the medium at a large incident angle, and has broadband and high efficiency characteristics.

[0055] 3. The electromagnetic anti-reflection unit provided by this invention can flexibly change the length of the horizontal and vertical metal arms of the metal patch according to application requirements, flexibly adjust the direction of the radiation zero point of the synthesized electric dipole, expand the angular domain during electromagnetic wave transmission, and realize electromagnetic anti-reflection at other incident angles.

[0056] 4. This invention utilizes a simple structure to achieve the artificial Brewster effect, which is convenient for mass production and can be used in new radar radomes and microwave imaging systems.

[0057] Based on the above theoretical analysis, simulation, and test results, it can be seen that for dielectric materials existing in nature, the artificial Brewster effect can be utilized. By loading and etching an "L"-shaped metal patch 3 onto a dielectric substrate 2, the radiation null point of the electric dipole at a large incident angle can be used to significantly improve the transmittance of electromagnetic waves through the dielectric at a large incident angle, and it also has broadband and wide-angle domain characteristics.

[0058] The technical solutions of the present invention are not limited to the specific examples mentioned above. For example, the present invention can be a dielectric substrate 1 with different dielectric properties and geometric dimensions. By changing the length and width of the dielectric substrate 2 and the "L"-shaped metal patch 3, the transmission effect of the substrate with corresponding electromagnetic parameters can be adjusted. All technical changes made according to the technical solutions of the present invention fall within the protection scope of the present invention.

[0059] The above-described embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any simple changes or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. An electromagnetic anti-reflective converter, characterized in that, It includes multiple superunits, which are arranged in a rectangular shape. Each superunit includes: Dielectric substrate (1); The dielectric substrate (2) is vertically disposed on top of the dielectric substrate (1); A metal patch (3) is in the shape of an inverted "L" and is disposed on one side of the dielectric substrate (2); wherein the metal patch (3) includes a horizontal arm and a vertical arm, one end of the horizontal arm is connected to the lower end of the vertical arm, and the length of the horizontal arm is greater than the length of the vertical arm; Electromagnetic waves in the air are incident from one side of the dielectric substrate (2) with metal patches (3), causing multiple supercells to resonate simultaneously. The electric field component of the transmitted electromagnetic waves excites electric dipoles of different lengths in the horizontal and vertical directions of the metal patches (3), which interfere with and cancel out the incident electromagnetic waves, so that the resonant zero point of the synthesized dipoles points to the direction of the reflected wave. The electromagnetic waves are transmitted forward from the gap channel between adjacent supercells.

2. The electromagnetic anti-reflective converter according to claim 1, characterized in that, The dielectric substrate (2) is located at the middle position on top of the dielectric substrate (1).

3. The electromagnetic anti-reflective converter according to claim 1, characterized in that, The metal patch (3) is etched on one side of the dielectric substrate (2), and its material is copper with a thickness of 20 μm.

4. The electromagnetic anti-reflective converter according to claim 1, characterized in that, The distance between the lower end of the horizontal arm and the top of the dielectric substrate (1) is equal to the distance between the end face of the vertical arm away from the horizontal arm and the end face of the dielectric substrate (2) on the same side.

5. The electromagnetic anti-reflective converter according to claim 1, characterized in that, The width of both the horizontal and vertical arms is 0.6 mm.

6. The electromagnetic anti-reflective converter according to claim 1, characterized in that, The dielectric substrate (1) and dielectric substrate (2) are both made of resin-based composite material, model FSD338N, and the thicknesses of the dielectric substrate (1) and dielectric substrate (2) are 3mm and 0.6mm, respectively.

7. The electromagnetic anti-reflective converter according to claim 1, characterized in that, The dielectric constant and loss of the dielectric substrate (1) are 4.3 and 0.025, respectively, and the dielectric constant and loss of the dielectric substrate (2) are 2.65 and 0.001, respectively.

8. The electromagnetic anti-reflective converter according to claim 1, characterized in that, The electromagnetic antireflective agent operates in the X-band, has an effective angular range of 70º-80º, and measures 590.4mm × 300mm.

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