A linear polarization wave arbitrary polarization angle converter

Abstract

The invention discloses a planar artificial electromagnetic structure linear polarization wave arbitrary polarization angle converter, which is used to realize angle deflection of linear polarization electromagnetic waves with arbitrary azimuth polarization. The resonance unit is composed of three parts: four rectangular copper patches, two insulating F4B dielectric substrates, and a copper metal ground substrate pressed between the two dielectric substrates. Two holes are drilled on the dielectric substrate, and copper is plated on the edges of the holes. The polarization conversion mechanism is: when a 5.8GHz linear polarization wave with arbitrary azimuth polarization is incident on the front of the structure, resonance is generated through the coupling of the planar monopole antenna, and the energy received by the front monopole antenna is coupled to the back monopole antenna through the copper-plated hole, and the angle rotation of the incident linear polarization wave is realized through the orthogonal decomposition of the incident electric field and the synthesis of the transmitted orthogonal electric field. Compared with the traditional polarization conversion device, the advantages are simple structure, adaptability to arbitrary angle conversion of linear polarization waves, low insertion loss, high polarization conversion efficiency, and low preparation cost.

Description

Technical Field

[0001] The invention belongs to electromagnetic technology, adopts a planar artificial electromagnetic structure, and specifically relates to an arbitrary polarization angle converter for linear polarization waves. Background Art

[0002] In today's information age, polarization converters, as an important device for controlling the propagation state of electromagnetic waves, are generally loaded at the front end of the antenna radiation aperture to switch and control the polarization state of the electromagnetic waves radiated. Polarization converters are widely used in wireless communications and microwave imaging. Artificial electromagnetic structures are periodic or non-periodic array structures composed of artificially designed units with special electromagnetic properties. These special electromagnetic functions are difficult or impossible to achieve with conventional materials in nature. Therefore, artificial electromagnetic structures have been widely used in the design of frequency selective surfaces, artificial absorbers, stealth functional materials and polarization converters.

[0003] When linearly polarized electromagnetic waves propagate in free space, due to the complexity of the space environment, scattering, refraction, and diffraction effects will occur, thereby changing the polarization direction of the electromagnetic waves. When the polarization direction of the electromagnetic wave is inconsistent with the polarization direction of the receiving antenna, the receiving efficiency will be reduced, and when the polarization directions of the two are orthogonal, the antenna can hardly receive the electromagnetic signal. Deflecting the polarization direction of the received signal to the polarization direction of the receiving antenna can make the antenna have the best receiving efficiency. Most linearly polarized wave polarization converters designed based on artificial electromagnetic structures have polarization selection characteristics, that is, the incident wave must be consistent with the polarization direction of the artificial electromagnetic structure unit, otherwise the incident wave will be reflected and the polarization conversion efficiency will be reduced. Therefore, it is increasingly important to design a polarization converter that is suitable for polarization conversion at any incident angle and has high efficiency. Summary of the invention

[0004] Purpose of the invention: In order to overcome the deficiencies of the prior art, a linear polarization wave arbitrary polarization angle converter is provided to adapt to the arbitrary angle conversion of linear polarization waves.

[0005] Technical solution: The present invention proposes a linear polarization wave arbitrary polarization angle converter, which adopts a planar artificial electromagnetic structure and is composed of an array of resonant units. The resonant unit includes three parts. The first part is composed of four rectangular copper patches, the second part is two F4B dielectric substrates, and the third part is a copper metal ground substrate, which is pressed between the two dielectric substrates; each unit structure in the array includes a copper patch, a copper-plated through hole, a copper metal ground substrate, and an F4B dielectric substrate; the copper patch is attached to the outer surface of the dielectric substrate, adjacent copper patches are orthogonal to each other, and the copper-plated hole is located on the copper patch.

[0006] Furthermore, each structure of the copper rectangular patch includes two pieces, a front side and a back side, and has a size of 12.7×3 mm.

[0007] Furthermore, two through holes are drilled at the border of each unit in the array and the edges are copper-plated, and the radius of the through holes is 0.4 mm; the size of the copper metal base plate is 21×21 mm.

[0008] Furthermore, the dielectric constant of the F4B dielectric board is 2.65 and the loss tangent is 0.001.

[0009] Furthermore, the resonant unit has a size of 21×21×8 mm and a thickness of 1 / 6 of the working wavelength.

[0010] Furthermore, the polarization conversion mechanism is as follows: when a 5.8 GHz linearly polarized wave with arbitrary azimuth polarization is incident on the front of the structure, resonance is generated through the coupling of the planar monopole antenna, and the energy received by the front monopole antenna is coupled to the back monopole antenna through the copper-plated hole, and the incident linearly polarized wave is converted into a linearly polarized wave through the orthogonal decomposition of the incident electric field and the synthesis of the transmitted orthogonal electric field. Angle rotation, where The angle between the polarization direction of the incident electric field and the x-axis of the orthogonal coordinate system is called the polarization azimuth.

[0011] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) It adopts a planar monopole artificial electromagnetic structure, which can orthogonally decompose linearly polarized waves with arbitrary azimuth polarization, thereby making the artificial electromagnetic structure of the present invention polarization insensitive; (2) It has a simple structure and is easy to process. By adjusting the geometric parameters of the unit structure, its operating frequency can be tuned; (3) It is light in weight, convenient for wireless communication or radar system integration, has low reflection loss, and has little interference with the transmitting antenna; (4) The resonant unit can be periodically expanded, has a flexible structure, is low in cost, and is easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of array structure;

[0013] Figure 2 (a) Schematic diagram of the front view of the unit structure; (b) Schematic diagram of the metal patch;

[0014] Figure 3 Illustration of polarization conversion mechanism: (a) decomposition diagram of the electric field vector of the incident line polarization wave; (b) synthesis diagram of the electric field vector of the transmitted line polarization wave;

[0015] Figure 4 (a) Co-polarization reflection coefficient of linear polarization waves with different polarization azimuths at normal incidence; (b) Polarization transmission coefficient of linear polarization waves with different polarization azimuths at normal incidence. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0017] like Figure 1As shown, the polarization angle converter is composed of 20×20 artificial unit structures arranged regularly along the orthogonal direction. In Figure 2(a) and Figure 2(b), the structure of each unit in the array is illustrated: Structures 1 and 2 are copper rectangular metal patches, each structure includes two pieces on the front and back sides, each piece has the same size of 12.7mm×3mm; Structure 3 is a copper-plated hole with a radius of 0.4mm; Structure 4 is a copper metal ground substrate with a size of 21mm×21mm; Structure 5 is two F4B dielectric substrates, each with a size of 21mm×21mm×4mm, a relative dielectric constant of 2.65, and a loss tangent of 0.001.

[0018] Figure 3 (a) is the polarization azimuth Schematic diagram of the polarization electric field vector of the normal incident ray, Figure 3 (b) is a schematic diagram of the linear polarization electric field vector after polarization conversion. Figure 3 The polarization switching mechanism is described in detail. Figure 3 Indicates the direction of each coordinate axis in the spherical coordinate system. E represents the incident electromagnetic wave of 5.8 GHz, the incident direction is the -z-axis, and it forms an arbitrary angle with the x-axis. Ex represents the x-axis component of the incident wave, and Ey represents the y-axis component of the incident wave, which are received by the copper patch monopole parallel to the x-axis and the copper patch monopole parallel to the y-axis respectively, and then transmitted and coupled to the copper patch perpendicular to the x-axis and the copper patch monopole perpendicular to the y-axis on the back through the copper-plated hole for radiation. After the transmission wave is synthesized, it forms a phase difference angle with the incident wave polarization azimuth. Ex' and Ey' represent the x-axis component and y-axis component of the transmitted wave, respectively.

[0019] Figure 4(a) shows the co-polarization reflection coefficient (S11) of the incident wave when the linear polarization wave with different polarization azimuth angles is incident normally. Figure 4(a) shows the simulation of array S11 when the electromagnetic wave is incident in various directions with respect to the x-axis. Figure 4(b) shows the polarization transmission coefficient (S12) of the incident wave when the linear polarization wave with different polarization azimuth angles is incident normally. Figure 4(b) shows the simulation of array polarization conversion efficiency when the electromagnetic wave is incident in various directions with respect to the x-axis. Figure 4(a) and 4(b) The polarization conversion effect of linear polarization waves with normal incidence in any polarization azimuth is verified. Figure 4(a) and 4(b) As shown in Figure 2, incident waves with different polarization orientations irradiate the sample, generating co-polarization reflection coefficients (S11) and The angular polarization transmission coefficient (S12) is completely the same, which verifies that the polarization converter sample designed by the present invention has the characteristic of converting linear polarization waves into any polarization angle, and the polarization conversion efficiency reaches more than 93%.

Claims

1. A linear polarization wave arbitrary polarization angle converter, comprising a planar artificial electromagnetic structure, characterized in that: The array is composed of resonant units, which include three parts. The first part is composed of copper rectangular patches of structures 1 and 2, each structure including two pieces on the front and back sides. The second part is two F4B dielectric substrates. The third part is a copper metal ground substrate, which is pressed between the two dielectric substrates. Each unit in the array includes a copper rectangular patch, a copper-plated through hole, a copper metal ground substrate, and an F4B dielectric substrate. The copper rectangular patch is attached to the outer surface of the dielectric substrate, and adjacent copper rectangular patches are orthogonal to each other. The copper-plated holes are located at On the copper rectangular patch, the polarization conversion mechanism is as follows: when a 5.8GHz linearly polarized wave with arbitrary azimuth polarization is incident on the front of the copper rectangular patch, the energy received by the monopole antenna of the copper rectangular patch on the front is coupled to the monopole antenna of the copper rectangular patch on the back through the copper-plated hole, and the orthogonal decomposition of the incident electric field and the synthesis of the transmitted orthogonal electric field are used to achieve an angular rotation of the incident linearly polarized wave by π / 2-2×φ, where φ is the angle between the polarization direction of the incident electric field and the x-axis of the orthogonal coordinate system, which is called the polarization azimuth.

2. The polarization angle converter according to claim 1, characterized in that: The copper rectangular patch measures 12.7×3mm.

3. The polarization angle converter according to claim 1, characterized in that: Two through holes are drilled on the edge of each unit in the array and copper is plated on the edges. The radius of the through hole is 0.4 mm. The size of the copper metal base plate is 21×21 mm.

4. The polarization angle converter according to claim 1, characterized in that: The dielectric constant of the F4B dielectric board is 2.65 and the loss tangent is 0.

001.

5. The polarization angle converter according to claim 1, characterized in that: The size of the resonant unit is 21×21×8mm, and the thickness is 1 / 6 of the working wavelength.

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