Electromagnetic metamaterial structural plate and coal mine underground communication system

Abstract

The invention provides an electromagnetic metamaterial structural plate and a coal mine underground communication system, and belongs to the field of mine communication. The electromagnetic metamaterial structural plate comprises a plurality of electromagnetic metamaterial units which are arranged in an array mode, and each electromagnetic metamaterial unit is provided with a metal wire used for conducting phase delay on electromagnetic wave signals. The line widths of the metal lines of the plurality of electromagnetic metamaterial units arranged in the array are gradually changed from the center of the array to the periphery of the array; and the plurality of electromagnetic metamaterial units arranged in the array are used for performing phase gradient regulation and control on the electromagnetic wave signals. The electromagnetic metamaterial structural plate provided by the invention is composed of a plurality of electromagnetic metamaterial units arranged in an array, and each electromagnetic metamaterial unit performs phase delay processing on an electromagnetic wave signal, so that the plurality of electromagnetic metamaterial units arranged in the array perform macroscopic phase gradient regulation and control on the electromagnetic signal; therefore, plane electromagnetic wave signals are focused, and signal enhancement is realized.

Description

Technical Field

[0001] The present invention relates to the field of mine communications, and in particular to an electromagnetic metamaterial structure plate and an underground coal mine communication system. Background Art

[0002] Coal resources, a vital energy source for social development and construction, are being mined on an ever-increasing scale. The goal of intelligent coal mines is to achieve multi-dimensional information perception, establish a rigorous risk management system, ensure the safety of coal miners, and create greater economic value for enterprises. The rapid development of advanced technologies such as Wi-Fi, 5G, and artificial intelligence has further advanced the process of intelligent coal mines. The rise of 5G communication technology, in particular, has seen widespread application in intelligent coal mines.

[0003] However, the communication environment in coal mines differs significantly from daily life on the surface. The underground terrain of coal mines is complex, with diverse tunnels and unique features such as corners and slopes. Furthermore, underground operations involve not only manual labor but also a large amount of machinery, conveyor belts, and ventilation ducts. Furthermore, the underground environment contains flammable and explosive substances such as coal dust and gas, all of which can interfere with underground wireless communications to varying degrees.

[0004] Underground coal mines have strict regulations for explosion-proof safety of electrical equipment. Because flammable and explosive gases like methane may be present underground, heating or sparking of electrical equipment can lead to explosions. Consequently, the upper limit for RF power of wireless transmitters must not exceed 6W. This regulation imposes significant technical restrictions on the use of equipment such as active antennas and wireless power systems, resulting in weak wireless communication signals and a poor communication environment in coal mines. Summary of the Invention

[0005] In order to solve the above-mentioned technical defects, the present invention provides an electromagnetic metamaterial structural plate and a coal mine underground communication system. The electromagnetic metamaterial structural plate is composed of a plurality of electromagnetic metamaterial units arranged in an array. Each electromagnetic metamaterial unit performs phase delay processing on the electromagnetic wave signal, so that the plurality of electromagnetic metamaterial units arranged in an array perform macroscopic phase gradient control on the electromagnetic signal, thereby focusing the planar electromagnetic wave signal and achieving signal enhancement.

[0006] A first aspect of the present invention provides an electromagnetic metamaterial structural plate, comprising: a plurality of electromagnetic metamaterial units arranged in an array, each electromagnetic metamaterial unit having a metal wire for phase delaying an electromagnetic wave signal; The line width of the metal wires of the electromagnetic metamaterial units arranged in a plurality of arrays changes gradually from the center of the array to the periphery of the array; Multiple arrayed electromagnetic metamaterial units are used to perform phase gradient control on electromagnetic wave signals.

[0007] In an embodiment of the present invention, the plurality of array-arranged electromagnetic metamaterial units include: the plurality of array-arranged electromagnetic metamaterial units include at least one first electromagnetic metamaterial unit, at least one second electromagnetic metamaterial unit, and at least one third electromagnetic metamaterial unit; The line width of the metal line of the first electromagnetic metamaterial unit is greater than the line width of the metal line of the second electromagnetic metamaterial unit, and the line width of the metal line of the second electromagnetic metamaterial unit is greater than the line width of the metal line of the third electromagnetic metamaterial unit; At least one third electromagnetic metamaterial unit is distributed in the center of the array, at least one second electromagnetic metamaterial unit is distributed outside the at least one third electromagnetic metamaterial unit, and at least one first electromagnetic metamaterial unit is distributed outside the at least one second electromagnetic metamaterial unit.

[0008] In an embodiment of the present invention, each electromagnetic metamaterial unit includes: a dielectric substrate; The metal wires of each electromagnetic metamaterial unit include: a first metal wire and a second metal wire, wherein the first metal wire and the second metal wire are respectively attached to two sides of the dielectric substrate; The first metal wire and the second metal wire are arranged in reverse symmetry, and the line width of the first metal wire and the second metal wire is the same; the first metal wire is used to phase delay the incident electromagnetic wave signal, and the second metal wire is used to generate a closed magnetic field loop based on the electromagnetic wave signal after the phase delay.

[0009] In the embodiment of the present invention, the dielectric substrate is an alumina ceramic plate, and the dielectric constant of the dielectric substrate is 9.8.

[0010] In an embodiment of the present invention, the first metal wire and the second metal wire are copper metal wires.

[0011] In an embodiment of the present invention, each electromagnetic metamaterial unit further includes two metal strips, and the two metal strips are respectively attached to two sides of the dielectric substrate; The first metal line and the second metal line are respectively located in the center areas of the two metal strips and are formed after etching the center areas of the two metal strips.

[0012] In an embodiment of the present invention, the first metal line is W-shaped, and the second metal line is inverted W-shaped; When an electromagnetic wave signal is irradiated on the first metal wire, the first metal wire couples with the electromagnetic wave signal, and charges are accumulated at the inflection points and end points of the W-shaped first metal wire, thereby forming local electric field energy storage and release, thereby achieving phase delay of the electromagnetic wave signal; The first metal wire and the second metal wire form a closed loop. When the phase-delayed electromagnetic wave signal passes through the dielectric substrate and reaches the second metal wire, the closed loop generates an alternating current to obtain a closed magnetic field loop, thereby achieving a magnetic dipole resonance response.

[0013] In the embodiment of the present invention, the bottom widths of the W-shaped first metal line and the inverted W-shaped second metal line are determined by the phase value that actually needs to be adjusted.

[0014] A second aspect of the present invention provides a coal mine underground communication system, comprising: an underground communication transmitting base station, an underground communication receiving base station, and the electromagnetic metamaterial structure plate as described above, wherein the electromagnetic metamaterial structure plate is arranged between the underground communication transmitting base station and the underground communication receiving base station; The downhole communication transmitting base station is used to transmit a first electromagnetic wave signal; The electromagnetic metamaterial structure plate is used to focus the first electromagnetic wave signal transmitted by the downhole communication transmitting base station; The focused first electromagnetic wave signal is received by the downhole communication receiving base station.

[0015] In an embodiment of the present invention, the system further comprises: a downhole communication terminal, wherein the electromagnetic metamaterial structure plate is further provided between the downhole communication receiving base station and the downhole communication terminal; The communication frequency domain of the downhole communication terminal is the same as the communication frequency domain of the downhole communication receiving base station; The underground communication receiving base station is used to transmit a second electromagnetic wave signal; The electromagnetic metamaterial structure plate is used to focus the second electromagnetic wave signal transmitted by the downhole communication receiving base station; The focused second electromagnetic wave signal is received by multiple downhole communication terminals. The electromagnetic metamaterial structural plate provided by the present invention is composed of multiple electromagnetic metamaterial units arranged in an array. Each electromagnetic metamaterial unit performs phase delay processing on the electromagnetic wave signal, so that the multiple electromagnetic metamaterial units arranged in an array perform macroscopic phase gradient regulation on the electromagnetic signal, thereby focusing the planar electromagnetic wave signal and achieving signal enhancement.

[0016] Other features and advantages of the technical solution of the present invention will be described in detail in the specific implementation section below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 1 is a schematic structural diagram of an electromagnetic metamaterial structure plate provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a metal strip provided in an embodiment of the present invention; Figure 3 1 is a structural block diagram of a coal mine underground communication system according to an embodiment of the present invention; Figure 4 1 is a schematic diagram of electromagnetic wave signal communication in a coal mine provided by an embodiment of the present invention; Figure 5 is a graph of S-parameter amplitude (dB) at vertical incidence of electromagnetic waves provided by an embodiment of the present invention; Figure 6 is a magnetic permeability parameter diagram for vertical incidence of electromagnetic waves provided by an embodiment of the present invention; Figure 7 is a dielectric constant parameter diagram of a vertically incident electromagnetic wave provided by an embodiment of the present invention; Figure 8 is a graph of S-parameter amplitude (dB) for parallel incident electromagnetic waves provided by an embodiment of the present invention; Figure 9 is a magnetic permeability parameter diagram for parallel incident electromagnetic waves provided by an embodiment of the present invention; Figure 10 4 is a diagram of dielectric constant parameters for parallel incident electromagnetic waves provided by an embodiment of the present invention.

[0018] Description of Reference Numerals 1-electromagnetic metamaterial structural plate, 11-first electromagnetic metamaterial unit, 12-second electromagnetic metamaterial unit, 13-third electromagnetic metamaterial unit, 111-dielectric substrate, 112-metal strip, 1121-first metal wire. DETAILED DESCRIPTION

[0019] To make the technical solutions and advantages of the embodiments of the present invention more clearly understood, exemplary embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It should be noted that the embodiments described are only a portion of the embodiments of the present invention, and are not an exhaustive list of all embodiments. It should be noted that the embodiments of the present invention and the features thereof may be combined with each other unless they conflict.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0022] In the present invention, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections, or communication; direct or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0023] During the development of this invention, the inventors discovered that coal resources, a vital energy source for social development and construction, are being mined on an ever-increasing scale. The goal of intelligent coal mines is to achieve multi-dimensional information perception, establish a strict risk management system, ensure the safety of coal miners, and create greater economic value for enterprises. The rapid development of advanced technologies such as WiFi, 5G, and artificial intelligence has further advanced the process of intelligent coal mines. In particular, the rise of 5G communication technology has seen widespread application in the field of intelligent coal mines. However, the communication environment in mines differs significantly from the daily environment on the surface. Coal mines have complex underground terrain structures, encompassing a variety of tunnels and unique terrain features such as corners and slopes. Furthermore, underground operations involve not only manual labor but also a large number of mechanical equipment, conveyor belts, and ventilation ducts. Furthermore, the underground environment contains flammable and explosive substances such as coal dust and gas, all of which interfere with underground wireless communications to varying degrees. Underground coal mine operations have strict regulations on the explosion-proof safety of electrical equipment. Because flammable and explosive gases such as gas may be present in the underground environment, overheating or sparking of electrical equipment can lead to explosions. Therefore, it is clearly stipulated that the upper limit of the radio frequency power of wireless transmitting equipment shall not exceed 6W. This regulation imposes greater technical restrictions on the application of equipment such as active antennas and wireless power supply systems, resulting in weak signal values ​​of wireless communication signals in coal mines and poor communication environment.

[0024] To address the above-mentioned issues, an embodiment of the present invention provides an electromagnetic metamaterial structural plate, comprising: a plurality of electromagnetic metamaterial units arranged in an array, each electromagnetic metamaterial unit having a metal wire for phase-delaying an electromagnetic wave signal; the line width of the metal wires of the plurality of array-arranged electromagnetic metamaterial units gradually changes from the center of the array to the periphery of the array; and the plurality of array-arranged electromagnetic metamaterial units are used to perform phase gradient control on the electromagnetic wave signal. The electromagnetic metamaterial structural plate disclosed in the present invention is composed of a plurality of array-arranged electromagnetic metamaterial units, each of which performs phase delay processing on the electromagnetic wave signal, so that the plurality of array-arranged electromagnetic metamaterial units perform macroscopic phase gradient control on the electromagnetic signal, thereby focusing the planar electromagnetic wave signal and achieving signal enhancement.

[0025] Figure 1 Schematic diagram of the structure of the electromagnetic metamaterial structure plate provided by the embodiment of the present invention. Figure 1 As shown, this embodiment provides an electromagnetic metamaterial structure plate 1, comprising: a plurality of electromagnetic metamaterial units arranged in an array, each electromagnetic metamaterial unit having a metal wire for phase delaying an electromagnetic wave signal; the line width of the metal wires of the plurality of array-arranged electromagnetic metamaterial units gradually changes from the center of the array to the periphery of the array; the plurality of array-arranged electromagnetic metamaterial units are used to perform phase gradient control on the electromagnetic wave signal.

[0026] Specifically, the electromagnetic metamaterial structure plate 1 comprises at least three types of electromagnetic metamaterial units with different metal line widths. The electromagnetic metamaterial units are arranged hierarchically according to the different metal line widths to achieve macroscopic phase gradient control of the electromagnetic wave signal by the entire electromagnetic metamaterial structure. Furthermore, in this embodiment, multiple electromagnetic metamaterial units are arranged in an 11*8 unit matrix, and the arrangement gradually changes from the center of the matrix to the periphery of the matrix according to the metal line width of the electromagnetic metamaterial unit to form a macroscopic phase gradient. Each of the electromagnetic metamaterial units is used to perform phase compensation on the electromagnetic wave signal passing through the corresponding position, thereby achieving signal enhancement.

[0027] In this embodiment, the multiple array-arranged electromagnetic metamaterial units include: the multiple array-arranged electromagnetic metamaterial units include at least one first electromagnetic metamaterial unit 11, at least one second electromagnetic metamaterial unit 12, and at least one third electromagnetic metamaterial unit 13; the line width of the metal wire of the first electromagnetic metamaterial unit 11 is greater than the line width of the metal wire of the second electromagnetic metamaterial unit 12, and the line width of the metal wire of the second electromagnetic metamaterial unit 12 is greater than the line width of the metal wire of the third electromagnetic metamaterial unit 13; at least one third electromagnetic metamaterial unit 13 is distributed in the center of the array, at least one second electromagnetic metamaterial unit 12 is distributed on the outside of at least one third electromagnetic metamaterial, and at least one first electromagnetic metamaterial unit 11 is distributed on the outside of at least one second electromagnetic metamaterial unit 12.

[0028] Specifically, the line width of the metal wire of the first electromagnetic metamaterial unit 11 is 1.5 mm, the line width of the metal wire of the second electromagnetic metamaterial unit 12 is 1.0 mm, and the line width of the metal wire of the third electromagnetic metamaterial unit 13 is 0.5 mm.

[0029] In this embodiment, each electromagnetic metamaterial unit further includes: a dielectric substrate 111; the metal wires of each electromagnetic metamaterial unit include: a first metal wire 1121 and a second metal wire, wherein the first metal wire 1121 and the second metal wire are respectively attached to two sides of the dielectric substrate 111; the first metal wire 1121 and the second metal wire are arranged in reverse symmetry, and the line width of the first metal wire 1121 and the second metal wire is the same; the first metal wire 1121 is used to phase delay the incident electromagnetic wave signal, and the second metal wire is used to generate a closed magnetic field loop based on the phase-delayed electromagnetic wave signal.

[0030] Specifically, the first metal wire 1121 and the second metal wire are obtained by etching the metal strips 112 attached to both sides of the dielectric substrate 111. Furthermore, the center area of ​​the metal strips 112 is etched to obtain the first metal wire 1121 and the second metal wire, respectively.

[0031] Figure 2 A schematic diagram of the structure of the metal strip 112 provided in an embodiment of the present invention is shown in FIG. Figure 2 As shown, the metal strips 112 are attached to the two surfaces of the dielectric substrate 111 respectively, and then the central area of ​​the metal strips 112 is etched to etch the metal lines on the dielectric substrate 111. The two metal lines are arranged symmetrically in opposite directions, which can achieve stronger electromagnetic wave control capabilities in a wider range of electromagnetic wave signal frequency bands.

[0032] Specifically, such as Figure 2 As shown, the first metal wire 1121 is W-shaped, and the second metal wire is an inverted M-shaped shape that is symmetrical to the W-shape. When an electromagnetic wave signal is irradiated on the first metal wire 1121, the first metal wire 1121 couples with the electromagnetic wave signal, and charges are accumulated at the inflection points and endpoints of the W-shaped first metal wire 1121, thereby forming local electric field energy storage and release, achieving phase delay of the electromagnetic wave signal; the first metal wire 1121 and the second metal wire form a closed loop. When the phase-delayed electromagnetic wave signal passes through the dielectric substrate 111 and reaches the second metal wire, the closed loop generates an alternating current, thereby obtaining a closed magnetic field loop, achieving a magnetic dipole resonance response.

[0033] Furthermore, the thickness of the metal strip 112 and the metal wire is 0.035 mm, the width of the metal strip 112 is 6 mm, the height of the metal strip 112 is 10 mm, the distance between the two bottom endpoints of the W shape of the first metal wire 1121 is 2 mm, and the overall height of W is 6 mm.

[0034] In this embodiment, the dielectric substrate 111 is an alumina ceramic plate, the dielectric constant of the dielectric substrate 111 is 9.8, and the thickness of the dielectric substrate 111 is 0.3 mm.

[0035] In this embodiment, the first metal wire 1121 and the second metal wire are copper metal wires.

[0036] In this embodiment, the width of the W-shaped bottom of the first W-shaped metal line 1121 and the inverted W-shaped second metal line is determined by the actual phase value to be adjusted. Specifically, the precise selection of the W-shaped bottom width and the thickness of the W-shaped metal line further enhances the phase adjustment capability of electromagnetic waves, resulting in better performance and greater adaptability in multiple frequency bands.

[0037] Figure 3 : is a structural block diagram of the coal mine underground communication system provided by the embodiment of the present invention, such as Figure 3 As shown, the second aspect of this embodiment provides a coal mine underground communication system, which includes: an underground communication transmitting base station, an underground communication receiving base station and an electromagnetic metamaterial structure plate 1; the electromagnetic metamaterial structure plate 1 is arranged between the underground communication transmitting base station and the underground communication receiving base station, and the underground communication transmitting base station is used to transmit a first electromagnetic wave signal; the electromagnetic metamaterial structure plate 1 is used to focus the first electromagnetic wave signal transmitted by the underground communication transmitting base station; the focused first electromagnetic wave signal is received by the underground communication receiving base station.

[0038] Furthermore, the system also includes: a downhole communication terminal, and the electromagnetic metamaterial structure plate 1 is also provided between the downhole communication receiving base station and the downhole communication terminal; the communication frequency domain of the downhole communication terminal is the same as the communication frequency domain of the downhole communication receiving base station; the downhole communication receiving base station is used to transmit a second electromagnetic wave signal; the electromagnetic metamaterial structure plate 1 is used to focus the second electromagnetic wave signal transmitted by the downhole communication receiving base station; the focused second electromagnetic wave signal is received by multiple downhole communication terminals.

[0039] In this embodiment, the electromagnetic metamaterial structure plate 1 in the coal mine underground communication system is specifically: It includes: multiple electromagnetic metamaterial units arranged in an array, each electromagnetic metamaterial unit has a metal wire for phase delaying the electromagnetic wave signal; the line width of the metal wires of the multiple electromagnetic metamaterial units arranged in an array gradually changes from the center of the array to the periphery of the array; the multiple electromagnetic metamaterial units arranged in an array are used to perform phase gradient control on the electromagnetic wave signal.

[0040] Specifically, the electromagnetic metamaterial structure plate 1 comprises at least three types of electromagnetic metamaterial units with different metal line widths. The electromagnetic metamaterial units are arranged hierarchically according to the different metal line widths to achieve macroscopic phase gradient control of the electromagnetic wave signal by the entire electromagnetic metamaterial structure. Furthermore, in this embodiment, multiple electromagnetic metamaterial units are arranged in an 11*8 unit matrix, and the arrangement gradually changes from the center of the matrix to the periphery of the matrix according to the metal line width of the electromagnetic metamaterial unit to form a macroscopic phase gradient. Each of the electromagnetic metamaterial units is used to perform phase compensation on the electromagnetic wave signal passing through the corresponding position, thereby achieving signal enhancement.

[0041] In this embodiment, the multiple array-arranged electromagnetic metamaterial units include: the multiple array-arranged electromagnetic metamaterial units include at least one first electromagnetic metamaterial unit 11, at least one second electromagnetic metamaterial unit 12, and at least one third electromagnetic metamaterial unit 13; the line width of the metal wire of the first electromagnetic metamaterial unit 11 is greater than the line width of the metal wire of the second electromagnetic metamaterial unit 12, and the line width of the metal wire of the second electromagnetic metamaterial unit 12 is greater than the line width of the metal wire of the third electromagnetic metamaterial unit 13; at least one third electromagnetic metamaterial unit 13 is distributed in the center of the array, at least one second electromagnetic metamaterial unit 12 is distributed on the outside of at least one third electromagnetic metamaterial, and at least one first electromagnetic metamaterial unit 11 is distributed on the outside of at least one second electromagnetic metamaterial unit 12.

[0042] Specifically, the line width of the metal wire of the first electromagnetic metamaterial unit 11 is 1.5 mm, the line width of the metal wire of the second electromagnetic metamaterial unit 12 is 1.0 mm, and the line width of the metal wire of the third electromagnetic metamaterial unit 13 is 0.5 mm.

[0043] In this embodiment, each electromagnetic metamaterial unit further includes: a dielectric substrate 111; the metal wires of each electromagnetic metamaterial unit include: a first metal wire 1121 and a second metal wire, wherein the first metal wire 1121 and the second metal wire are respectively attached to two sides of the dielectric substrate 111; the first metal wire 1121 and the second metal wire are arranged in reverse symmetry, and the line width of the first metal wire 1121 and the second metal wire is the same; the first metal wire 1121 is used to phase delay the incident electromagnetic wave signal, and the second metal wire is used to generate a closed magnetic field loop based on the phase-delayed electromagnetic wave signal.

[0044] Specifically, the first metal wire 1121 and the second metal wire are obtained by etching the metal strips 112 attached to both sides of the dielectric substrate 111. Furthermore, the center area of ​​the metal strips 112 is etched to obtain the first metal wire 1121 and the second metal wire, respectively.

[0045] Figure 2 A schematic diagram of the structure of the metal strip 112 provided in an embodiment of the present invention is shown in FIG. Figure 2 As shown, the metal strips 112 are attached to the two surfaces of the dielectric substrate 111 respectively, and then the central area of ​​the metal strips 112 is etched to etch the metal lines on the dielectric substrate 111. The two metal lines are arranged symmetrically in opposite directions, which can achieve stronger electromagnetic wave control capabilities in a wider range of electromagnetic wave signal frequency bands.

[0046] Specifically, such as Figure 2 As shown, the first metal wire 1121 is W-shaped, and the second metal wire is an inverted M-shaped shape that is symmetrical to the W-shape. When an electromagnetic wave signal is irradiated on the first metal wire 1121, the first metal wire 1121 couples with the electromagnetic wave signal, and charges are accumulated at the inflection points and endpoints of the W-shaped first metal wire 1121, thereby forming local electric field energy storage and release, achieving phase delay of the electromagnetic wave signal; the first metal wire 1121 and the second metal wire form a closed loop. When the phase-delayed electromagnetic wave signal passes through the dielectric substrate 111 and reaches the second metal wire, the closed loop generates an alternating current, thereby obtaining a closed magnetic field loop, achieving a magnetic dipole resonance response.

[0047] Furthermore, the thickness of the metal strip 112 and the metal wire is 0.035 mm, the width of the metal strip 112 is 6 mm, the height of the metal strip 112 is 10 mm, the distance between the two bottom endpoints of the W shape of the first metal wire 1121 is 2 mm, and the overall height of W is 6 mm.

[0048] In this embodiment, the dielectric substrate 111 is an alumina ceramic plate, the dielectric constant of the dielectric substrate 111 is 9.8, and the thickness of the dielectric substrate 111 is 0.3 mm.

[0049] In this embodiment, the first metal wire 1121 and the second metal wire are copper metal wires.

[0050] In this embodiment, the width of the W-shaped bottom of the first W-shaped metal line 1121 and the inverted W-shaped second metal line is determined by the actual phase value to be adjusted. Specifically, the precise selection of the W-shaped bottom width and the thickness of the W-shaped metal line further enhances the phase adjustment capability of electromagnetic waves, resulting in better performance and greater adaptability in multiple frequency bands.

[0051] Specifically, in the application scenario of the existing coal mine underground communication system, the coal mine underground communication transmitting base station transmits a communication signal directed to the coal mine underground communication receiving base station. However, due to the complex environment of the coal mine underground, interference such as multipath effect will be generated, and the signal received by the coal mine underground communication receiving base station is seriously interfered with. Figure 4 FIG. 1 is a schematic diagram of an embodiment of the present invention providing a communication diagram of electromagnetic wave signals in a coal mine. Figure 4 As shown, the system includes an underground communication transmitting base station, an electromagnetic metamaterial structure plate 1, and an underground communication receiving base station. The underground communication transmitting base station is used to transmit underground wireless communication signals (electromagnetic wave signals); the electromagnetic metamaterial structure plate 1 is used to focus the wireless communication signals; and the underground communication receiving base station is used to receive wireless communication signals underground in the coal mine. In this embodiment, by introducing three W-shaped metal wires with line widths of 0.5mm, 1mm, and 1.5mm, and arranging them in a periodic manner in an 11×8 unit matrix, a spatial phase gradient can be generated on a macroscopic scale. The introduction of the electromagnetic metamaterial structure plate 1 is primarily to perform a first operation on the wireless communication signal, thereby increasing coverage distance and improving communication quality, such as phase adjustment or signal enhancement.

[0052] Specifically, this embodiment provides a W-shaped electromagnetic metamaterial structure: the structural dimensions are as follows: a metal strip 112 with a width b of 6 mm and a W-shaped metal wire are placed in an anti-symmetrical manner on both sides of a dielectric plate with a width a=8 mm, a height L=10 mm, and a thickness d=0.3 mm. The height h of the W-shaped metal wire is 6 mm, the line width t is 1 mm, the bottom width of the W-shaped metal wire is s=2 mm, and the thickness of the W-shaped metal wire is 0.035 mm. The dielectric constant of the alumina ceramic dielectric plate is 9.8, and the material of the metal strip 112 is copper. The anti-symmetrical arrangement of the W-shaped metal wire can achieve stronger electromagnetic wave control capabilities in a wider frequency band. The W-shaped electromagnetic metamaterial can produce more complex resonance phenomena within a specific frequency range, thereby improving the propagation and control effects of electromagnetic waves.

[0053] The width and height of the metal strips 112 in the W-shaped electromagnetic metamaterial structure of this application have been precisely calculated and optimized to effectively enhance the metamaterial's electromagnetic response, particularly exhibiting excellent electromagnetic wave transmittance and reflection characteristics at high frequencies. Adjusting the line width t of the W-shaped metal strips effectively alters the metamaterial's electromagnetic wave transmission characteristics, thereby adjusting its phase response.

[0054] In addition, the precise selection of the W-shaped bottom width and the thickness of the W-shaped metal wire further enhances the phase adjustment capability of electromagnetic waves. This structure performs better in multiple frequency bands and has stronger adaptability.

[0055] Each electromagnetic metamaterial unit is able to correct the phase of the electromagnetic wave at its location.

[0056] In this embodiment, the electromagnetic metamaterial structure is analyzed according to the vertical and parallel incident directions of the electromagnetic wave. The electromagnetic wave is analyzed vertically incident on the dielectric substrate 111. Figure 5 is a graph of the S-parameter amplitude (dB) of a vertically incident electromagnetic wave provided by an embodiment of the present invention, Figure 6 is a magnetic permeability parameter diagram of a vertically incident electromagnetic wave provided by an embodiment of the present invention, Figure 7 is a diagram of dielectric constant parameters for vertical incidence of electromagnetic waves provided by an embodiment of the present invention, such as Figure 5 、 Figure 6 and Figure 7 As shown in the figure, the equivalent dielectric constant and equivalent permeability of the structure are both negative in the 17.52~17.92GHz band, and a left-hand passband appears. When the electromagnetic wave is incident parallel to the Figure 8 is a graph of the S-parameter amplitude (dB) of parallel incident electromagnetic waves provided by an embodiment of the present invention, Figure 9 is a magnetic permeability parameter diagram of parallel incident electromagnetic waves provided by an embodiment of the present invention, Figure 10 is a dielectric constant parameter diagram of parallel incident electromagnetic waves provided by an embodiment of the present invention, such as Figure 8 、 Figure 9 as well as Figure 10 As shown in Figure 3, the equivalent dielectric constant and equivalent permeability of the structure are both negative in the frequency band of 15.62~15.78GHz, showing a left-handed characteristic.

[0057] Under both incident conditions, the electromagnetic metamaterial structure composed of two anti-symmetrical W-shaped metal wires on the front and back of the dielectric substrate 111 can couple to produce magnetic resonance under the influence of the electromagnetic wave's magnetic field component, thereby achieving negative magnetic permeability. However, the magnetic resonance coupling principles under the two conditions are different. When the electromagnetic wave is incident perpendicularly on the dielectric substrate 111, the W-shaped metal wires on both sides of the dielectric substrate 111 couple with each other, forming magnetic resonance and generating negative magnetic permeability. When the electromagnetic wave is incident parallel to the dielectric substrate 111, the anti-symmetrical placement of the W-shaped metal wires on both sides of the dielectric substrate 111 forms a ring circuit, generating magnetic resonance and achieving negative magnetic permeability. In both cases, the negative dielectric constant is generated by the plasmon effect of the W-shaped metal wires themselves, thus achieving a two-dimensional double negative characteristic.

[0058] In summary, the present invention proposes using electromagnetic metamaterial units as the basic building blocks of an electromagnetic metamaterial structural plate 1. By varying the geometric parameters of these units, the phase of wireless transmission signals can be adjusted. By rationally arranging electromagnetic metamaterial units with varying structural parameters to form an electromagnetic metamaterial structural plate 1, the electromagnetic metamaterial structural plate 1 is utilized to focus underground coal mine communication signals, thereby increasing the gain of wireless communication signals. This electromagnetic metamaterial structural plate 1 effectively improves the reliability of wireless communication in underground coal mines.

[0059] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0060] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0061] The above describes in detail the optional embodiments of the present invention in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, a variety of simple variations can be made to the technical solutions of the embodiments of the present invention, and these simple variations all fall within the scope of protection of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction, and as long as the combination does not violate the concept of the embodiments of the present invention, it should also be regarded as the content disclosed in the embodiments of the present invention.

Claims

1. An electromagnetic metamaterial structure plate, characterized in that: include: A plurality of electromagnetic metamaterial units arranged in an array, each electromagnetic metamaterial unit having a metal wire for phase-delaying an electromagnetic wave signal; The line width of the metal wires of the electromagnetic metamaterial units arranged in a plurality of arrays changes gradually from the center of the array to the periphery of the array; Multiple arrayed electromagnetic metamaterial units are used to perform phase gradient control on electromagnetic wave signals.

2. The electromagnetic metamaterial structure plate according to claim 1, characterized in that: The plurality of arrayed electromagnetic metamaterial units include at least one first electromagnetic metamaterial unit, at least one second electromagnetic metamaterial unit, and at least one third electromagnetic metamaterial unit; The line width of the metal line of the first electromagnetic metamaterial unit is greater than the line width of the metal line of the second electromagnetic metamaterial unit, and the line width of the metal line of the second electromagnetic metamaterial unit is greater than the line width of the metal line of the third electromagnetic metamaterial unit; At least one third electromagnetic metamaterial unit is distributed in the center of the array, at least one second electromagnetic metamaterial unit is distributed outside the at least one third electromagnetic metamaterial unit, and at least one first electromagnetic metamaterial unit is distributed outside the at least one second electromagnetic metamaterial unit.

3. The electromagnetic metamaterial structure plate according to claim 1, characterized in that: Each electromagnetic metamaterial unit includes: a dielectric substrate; The metal wires of each electromagnetic metamaterial unit include: a first metal wire and a second metal wire, wherein the first metal wire and the second metal wire are respectively attached to two sides of the dielectric substrate; The first metal line and the second metal line are arranged in reverse symmetry, and the line widths of the first metal line and the second metal line are the same; The first metal wire is used to phase-delay an incident electromagnetic wave signal, and the second metal wire is used to generate a closed magnetic field loop based on the phase-delayed electromagnetic wave signal.

4. The electromagnetic metamaterial structure plate according to claim 3, characterized in that: The dielectric substrate is an alumina ceramic plate, and the dielectric constant of the dielectric substrate is 9.

8.

5. The electromagnetic metamaterial structure plate according to claim 3, characterized in that: The first metal wire and the second metal wire are copper metal wires.

6. The electromagnetic metamaterial structure plate according to claim 3, characterized in that: Each electromagnetic metamaterial unit also includes two metal strips, which are attached to two sides of the dielectric substrate respectively; The first metal line and the second metal line are respectively located in the center areas of the two metal strips and are formed after etching the center areas of the two metal strips.

7. The electromagnetic metamaterial structure plate according to claim 3, characterized in that: The first metal line is W-shaped, and the second metal line is inverted W-shaped; When an electromagnetic wave signal is irradiated on the first metal wire, the first metal wire couples with the electromagnetic wave signal, and charges are accumulated at the inflection points and end points of the W-shaped first metal wire, thereby forming local electric field energy storage and release, thereby achieving phase delay of the electromagnetic wave signal; The first metal wire and the second metal wire form a closed loop. When the phase-delayed electromagnetic wave signal passes through the dielectric substrate and reaches the second metal wire, the closed loop generates an alternating current to obtain a closed magnetic field loop, thereby achieving a magnetic dipole resonance response.

8. The electromagnetic metamaterial structure plate according to claim 7, characterized in that: The bottom widths of the W-shaped first metal line and the inverted W-shaped second metal line are determined by the phase value that needs to be adjusted.

9. A coal mine underground communication system, characterized in that: include: An underground communication transmitting base station, an underground communication receiving base station, and an electromagnetic metamaterial structure plate according to any one of claims 1 to 8; The electromagnetic metamaterial structure plate is arranged between the downhole communication transmitting base station and the downhole communication receiving base station; The downhole communication transmitting base station is used to transmit a first electromagnetic wave signal; The electromagnetic metamaterial structure plate is used to focus the first electromagnetic wave signal transmitted by the downhole communication transmitting base station; The focused first electromagnetic wave signal is received by the downhole communication receiving base station.

10. The underground coal mine communication system according to claim 9, characterized in that: The system further comprises: a downhole communication terminal, wherein the electromagnetic metamaterial structure plate is further provided between the downhole communication receiving base station and the downhole communication terminal; The communication frequency domain of the downhole communication terminal is the same as the communication frequency domain of the downhole communication receiving base station; The underground communication receiving base station is used to transmit a second electromagnetic wave signal; The electromagnetic metamaterial structure plate is used to focus the second electromagnetic wave signal transmitted by the downhole communication receiving base station; The focused second electromagnetic wave signal is received by multiple downhole communication terminals.

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