An electromagnetic metamaterial array for corona discharge detection

Abstract

The present invention discloses an electromagnetic metamaterial array for corona discharge detection, which relates to the field of corona discharge detection and is composed of a plurality of electromagnetic metamaterial units arranged in a matrix; the electromagnetic metamaterial unit comprises a first metal patch layer, a dielectric layer and a second metal patch layer which are sequentially bonded and connected; the first metal patch layer comprises a right-handed swastika-shaped main body, the right-handed swastika-shaped main body comprises four first arms, the intersection point of the four first arms is the center point of the right-handed swastika-shaped main body, and the first arm is a serpentine structure. The electromagnetic metamaterial array structure of the present invention can be directly used to prepare a corona discharge detection antenna, and at the same time, can be installed on an existing antenna as an auxiliary device, and when installed on an existing antenna, it can effectively improve the antenna's ability to receive electromagnetic waves.

Description

Technical Field

[0001] The present invention relates to the field of corona discharge detection, and in particular to an electromagnetic metamaterial array for corona discharge detection, which is used to improve the sensitivity of a corona discharge detection antenna. Background Art

[0002] In overhead lines, poor contact between the line and insulator fittings, dirty insulator surface, aging of insulators, broken line strands, etc. will lead to uneven local electric field distribution and easy occurrence of corona discharge. The generation of corona discharge will not only cause energy loss, but also affect wireless communication. Therefore, timely and accurate detection of corona discharge is of great significance to the safe operation of transmission lines.

[0003] The current mainstream detection method is to use a small antenna to detect the electromagnetic wave signal released by corona discharge. However, the miniaturized antenna has the disadvantages of short detection distance and weak detection ability. In order to improve the detection ability of the antenna, the present invention introduces an electromagnetic metamaterial, which is combined with the detection antenna to improve the detection ability of the detection antenna.

[0004] Electromagnetic metamaterials are a unique artificial electromagnetic material structure consisting of periodically arranged units. This periodic structure has selective reflection or transmission characteristics for incident electromagnetic waves of different frequencies, so it can effectively control the reflection and transmission characteristics of electromagnetic waves. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an electromagnetic metamaterial for corona discharge detection.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] Provided is an electromagnetic metamaterial array for corona discharge detection, which is composed of a plurality of electromagnetic metamaterial units arranged in a matrix;

[0008] The electromagnetic metamaterial unit package includes a first metal patch layer, a dielectric layer, and a second metal patch layer that are sequentially bonded and connected; the first metal patch layer includes a right-handed swastika-shaped body, the right-handed swastika-shaped body includes four first arms, the intersection point of the four first arms is the center point of the right-handed swastika-shaped body, and the first arm is a serpentine structure; the end of the first arm away from the center of the right-handed swastika-shaped body is connected to the second arm; the end of the second arm away from the first arm is provided with a third arm perpendicular to the second arm; a gap is provided between the end of the third arm away from the connected second arm and another first arm;

[0009] The second metal patch layer comprises a cross-shaped main body, and lumped elements are respectively arranged on four arms of the cross-shaped main body.

[0010] Furthermore, the dielectric layer is a square plate made of FR4 epoxy glass cloth.

[0011] Furthermore, the first metal patch layer and the second metal patch layer are metal copper or metal silver.

[0012] Furthermore, the inductance value of the lumped element is determined according to the size of the first metal patch layer, and the specific method is as follows:

[0013] S1: Establish a first-order series capacitor-inductor combined resonant circuit based on the first metal patch layer;

[0014] S2: Calculate and simulate the first-order series capacitor-inductor combined resonant circuit to obtain the parameters of the first-order series capacitor-inductor combined resonant circuit;

[0015] S3: adding the equivalent circuit of the second metal patch layer to the first-order series capacitor-inductor combined resonant circuit to obtain a total equivalent circuit, optimizing the total equivalent circuit to obtain the inductance value of the lumped element.

[0016] Furthermore, in step S3, when the total equivalent circuit is optimized, the operating frequency of the total equivalent circuit is set to the corona discharge detection frequency band of 100 MHz-500 MHz.

[0017] Furthermore, the dielectric layer is a square with a side length of l; a gap is provided between the edge of the first metal patch layer and the edge of the dielectric layer; and one end of the four arms of the cross-shaped body of the second metal patch layer away from the center of the cross-shaped body is bonded to the dielectric layer.

[0018] Furthermore, the interval between two adjacent serpentine structures of the first metal patch layer, the interval between two adjacent parallel lines in the serpentine structure, and the interval between the second arm and the adjacent serpentine structure are all the same; and the thickness of the first metal patch layer is the same as the thickness of the second metal patch layer.

[0019] The above-mentioned electromagnetic metamaterial unit for corona discharge detection is used to prepare a corona discharge electromagnetic metamaterial unit array, which is used to assist in improving the ability of an existing antenna to receive electromagnetic waves. Specifically, the electromagnetic metamaterial array is arranged in parallel on a side of the existing antenna close to the receiving surface, and the electromagnetic metamaterial array is arranged at a distance from the existing antenna.

[0020] Furthermore, the area of ​​the electromagnetic metamaterial array is larger than that of the existing antenna.

[0021] The beneficial effects of the present invention are:

[0022] The present invention provides a first metal patch layer, a dielectric layer and a second metal patch layer; a right-handed swastika-shaped body formed by the serpentine structure of the first arm, the second arm and the third arm connected in sequence as the first metal patch layer, and a lumped element is provided in the second metal patch layer, so that the low-bandwidth passband effect of the electromagnetic metamaterial can be effectively achieved, and the structure is simple and easy to process. The electromagnetic metamaterial array structure of the present invention can be directly used to prepare a corona discharge detection antenna, and at the same time, can be installed on an existing antenna as an auxiliary device, and when installed on an existing antenna, it can effectively improve the antenna's ability to receive electromagnetic waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the electromagnetic metamaterial unit array;

[0024] Figure 2 is a schematic structural diagram of the first metal patch layer;

[0025] Figure 3 is a schematic diagram of the structure of the second metal patch layer;

[0026] Figure 4 Schematic diagram of the equivalent circuit of the electromagnetic metamaterial unit structure;

[0027] Figure 5 The S11 curve diagram of the electromagnetic metamaterial unit structure and the corresponding equivalent circuit;

[0028] Figure 6 Schematic diagram of an electromagnetic metamaterial unit array device loaded on a serpentine Hilbert fractal antenna;

[0029] Figure 7 The S11 curve of the electromagnetic metamaterial unit array loaded on the serpentine Hilbert fractal antenna;

[0030] Among them, 1. the first arm; 2. the second arm; 3. the third arm; 4. the cross-shaped body; 5. the lumped element. DETAILED DESCRIPTION

[0031] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0032] Example 1

[0033] like Figure 1As shown, an electromagnetic metamaterial array for corona discharge detection is composed of 5*5 selective surface units.

[0034] like Figure 2-3 As shown, the electromagnetic metamaterial unit includes a first metal patch layer, a dielectric layer, and a second metal patch layer that are sequentially bonded and connected; the first metal patch layer includes a right-handed swastika-shaped body, the right-handed swastika-shaped body includes four first arms 1, the intersection point of the four first arms 1 is the center point of the right-handed swastika-shaped body, and the first arm 1 is a serpentine structure; the end of the first arm 1 away from the center of the right-handed swastika-shaped body is connected to the second arm 2; the end of the second arm 2 away from the first arm 1 is provided with a third arm 3 perpendicular to the second arm 2; a gap is provided between the end of the third arm 3 away from the connected second arm 2 and another first arm 1;

[0035] The second metal patch layer includes a cross-shaped body 4, and the centers of the four arms of the cross-shaped body 4 are respectively provided with lumped elements 5. In specific implementation, the lumped elements 5 can also be located at one end of the four arms away from the center of the cross-shaped body 4.

[0036] The dielectric layer is a square plate made of FR4 epoxy glass cloth. In specific implementation, the dielectric layer can also be a square plate made of insulating materials such as electrical wood boards.

[0037] The first metal patch layer and the second metal patch layer are made of metal copper or metal silver. In specific implementation, the first metal patch layer and the second metal patch layer can also be made of other conductive non-ferromagnetic metal materials.

[0038] The inductance value of the lumped element 5 is determined according to the size of the first metal patch layer, and the specific method is as follows:

[0039] S1: Establish a first-order series capacitor-inductor combined resonant circuit based on the first metal patch layer;

[0040] S2: Calculate and simulate the first-order series capacitor-inductor combined resonant circuit to obtain the parameters of the first-order series capacitor-inductor combined resonant circuit;

[0041] S3: adding the equivalent circuit of the second metal patch layer to the first-order series capacitor-inductor combined resonant circuit to obtain a total equivalent circuit;

[0042] According to Flouet's theorem, given a transmission mode and frequency, the field in any plane differs from the field in a plane with a certain period by only a complex constant. When studying the electromagnetic properties of the electromagnetic metamaterial of the present invention, the electromagnetic properties of the entire structure can be obtained by studying only one unit. Therefore, the present invention mainly analyzes one unit.

[0043] In the specific implementation, the simulation software CSTSTUDIOSUITE2023 is used for simulation calculation, and the following is obtained: Figure 3 The equivalent circuit diagram shown includes the equivalent capacitance C of the first metal patch layer. 1 , C 2 , inductance L 1 , L 2 , the equivalent inductance L of the second metal patch layer 3 And the equivalent resistance of the dielectric layer (Z 1 , h), where impedance h is the thickness of the dielectric layer, Z 0 is the free wave impedance of free space; the operating frequency of the total equivalent circuit is set to the corona discharge detection frequency band of 100MHz-500MHz, the total equivalent circuit is optimized, and the inductance value of the lumped element is obtained. Its various parameters are shown in Table 1.

[0044] Table 1

[0045] parameter <![CDATA[C 1 ]]> <![CDATA[C 2 ]]> <![CDATA[L 1 ]]> Numeric 173.404fF 226.823fF 5.26259nH <![CDATA[L 2 ]]> <![CDATA[L 3 ]]> <![CDATA[Z 0 ]]> <![CDATA[Z 1 ]]> 46.3126nH 780nH 377Ω 182Ω

[0046] The dielectric layer is a square with a side length of l; a gap is provided between the edge of the first metal patch layer and the edge of the dielectric layer; and one end of the four arms of the cross-shaped body 4 of the second metal patch layer away from the center of the cross-shaped body 4 is attached to the dielectric layer.

[0047] In the specific implementation, the side length of the dielectric layer is l=10mm; and the thickness of the dielectric layer is h=1.6mm. The interval between two adjacent serpentine structures of the first metal patch layer, the interval between two adjacent parallel lines in the serpentine structure, and the interval between the second branch arm 2 and the adjacent serpentine structure are all the same, which is d2=0.2mm; the length of the third branch arm 3 of the first metal patch layer is d1=4.4mm; and the gap between the end of the third branch arm 3 away from the connected second branch arm 2 and the adjacent other first branch arm 1 is 0.3mm; the interval between the end of the first branch arm 1 of the first metal patch layer close to the center of the right-handed swastika body and the serpentine structure of the adjacent first branch arm 1 is d3=0.2mm; the gap between the starting section of the serpentine structure of the first metal patch layer and the first branch arm 1 parallel to it is d4=0.5mm; the widths of the first branch arm 1, the second branch arm 2 and the third branch arm 3 of the first metal patch layer are all w1=0.2mm; the width of the four branches of the cross-shaped body 4 of the second metal patch layer is w2=0.4mm. The thickness of the first metal patch layer is the same as that of the second metal patch layer, which is 0.035 mm.

[0048] The S11 curves are obtained by simulating the electromagnetic metamaterial structure and the corresponding equivalent circuit. Figure 5 As shown by Figure 5It can be seen that the frequency of the first resonance point of the frequency selective surface unit structure (FSS) is 240MHz, corresponding to a free space wavelength of 1.25 meters, which is located in the low-frequency band. The electromagnetic metamaterial unit size proposed in the present invention is 0.0083 resonance wavelengths, where the resonance wavelength is the wavelength of electromagnetic waves propagating in free space. The frequency band corresponding to less than -10dB in the S11 curve of the electromagnetic metamaterial unit structure (FSS) is 100-630MHz, and the passband is 530MHz. The first resonance frequency and passband width of the corresponding equivalent circuit (DCM) S11 curve are basically the same as those of the electromagnetic metamaterial unit structure. The simulation results of the metamaterial array with 5×5 units are exactly the same as those of the unit simulation.

[0049] Example 2

[0050] An electromagnetic metamaterial array is provided to assist in improving the ability of an existing antenna to receive electromagnetic waves. In this embodiment, a serpentine Hilbert fractal antenna (SHU) disclosed in application number CN116365214A is selected as the antenna to be improved; the size of the SHU antenna is set to 130 mm×130 mm×1.6 mm;

[0051] Arrange electromagnetic metamaterial units in a 15×15 matrix, and replace the dielectric layer of the electromagnetic metamaterial arranged in the matrix with a dielectric layer as a whole having a size of 150 mm×150 mm×1.6 mm, as an electromagnetic metamaterial array;

[0052] The SHU antenna is used as a blank group, and the electromagnetic metamaterial array is used to load the SHU antenna. The loading method is as follows Figure 6 As shown. The interval H is set to 10mm, 20mm, 30mm and 40mm respectively; the antenna is simulated and the S11 curve changes as shown in the simulation result. Figure 7 As shown by Figure 7 It can be seen that the S11 curves of the antennas equipped with electromagnetic metamaterial arrays are significantly lower than those of the blank group, which means that the antenna auxiliary device can effectively improve the antenna's ability to receive electromagnetic waves. When H = 20 mm, the antenna has the strongest ability to receive electromagnetic waves.

[0053] The above simulation results show that the electromagnetic metamaterial structure proposed in the present invention achieves the requirements of low resonant frequency and miniaturization of frequency selective surface, while improving the ability of the antenna to capture electromagnetic waves.

Claims

1. An electromagnetic metamaterial array for corona discharge detection, characterized in that: It is composed of a number of electromagnetic metamaterial units arranged in a matrix; The electromagnetic metamaterial unit comprises a first metal patch layer, a dielectric layer and a second metal patch layer which are sequentially bonded and connected; the first metal patch layer comprises a right-handed swastika-shaped body, the right-handed swastika-shaped body comprises four first arms, the intersection point of the four first arms is the center point of the right-handed swastika-shaped body, and the first arm is a serpentine structure; the first arm is connected to a second arm at one end away from the center of the right-handed swastika-shaped body; the second arm is provided with a third arm perpendicular to the second arm at one end away from the first arm; a gap is provided between one end of the third arm away from the connected second arm and another first arm; The second metal patch layer includes a cross-shaped body, and lumped elements are respectively arranged on four arms of the cross-shaped body.

2. The electromagnetic metamaterial array for corona discharge detection according to claim 1, characterized in that: The dielectric layer is a square plate made of FR4 epoxy glass cloth.

3. The electromagnetic metamaterial array for corona discharge detection according to claim 1, characterized in that: The first metal patch layer and the second metal patch layer are metal copper or metal silver.

4. The electromagnetic metamaterial array for corona discharge detection according to claim 1, characterized in that: The inductance value of the lumped element is determined according to the size of the first metal patch layer, and the specific method is as follows: S1: Establish a first-order series capacitor-inductor combined resonant circuit based on the first metal patch layer; S2: Calculate and simulate the first-order series capacitor-inductor combined resonant circuit to obtain the parameters of the first-order series capacitor-inductor combined resonant circuit; S3: adding the equivalent circuit of the second metal patch layer to the first-order series capacitor-inductor combined resonant circuit to obtain a total equivalent circuit, optimizing the total equivalent circuit to obtain the inductance value of the lumped element.

5. The electromagnetic metamaterial array for corona discharge detection according to claim 4, characterized in that: In the step S3, when the total equivalent circuit is optimized, the operating frequency of the total equivalent circuit is set to the corona discharge detection frequency band of 100 MHz-500 MHz.

6. The electromagnetic metamaterial array for corona discharge detection according to claim 1, characterized in that: The dielectric layer is a square with a side length of l; a gap is provided between the edge of the first metal patch layer and the edge of the dielectric layer; and one end of the four arms of the cross-shaped body of the second metal patch layer away from the center of the cross-shaped body is attached to the dielectric layer.

7. The electromagnetic metamaterial array for corona discharge detection according to claim 6, characterized in that: The interval between two adjacent serpentine structures of the first metal patch layer, the interval between two adjacent parallel lines in the serpentine structure, and the interval between the second arm and the adjacent serpentine structure are all the same; and the thickness of the first metal patch layer is the same as the thickness of the second metal patch layer.

8. An application of the electromagnetic metamaterial array for corona discharge detection according to any one of claims 1 to 7, characterized in that: It is used to assist in improving the ability of an existing antenna to receive electromagnetic waves. Specifically, the electromagnetic metamaterial array is arranged in parallel on a side of the existing antenna close to the receiving surface, and the electromagnetic metamaterial array is arranged at a distance from the existing antenna.

9. The use according to claim 8, characterized in that: The area of ​​the metamaterial array is larger than that of the existing antenna.

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