Dual-frequency electromagnetic metasurface unit, array and method for enhancing underground signal coverage

Abstract

The invention relates to a dual-frequency electromagnetic metasurface unit, array and method for enhancing underground signal coverage, and the metasurface unit comprises a dielectric layer which comprises a first dielectric layer and a second dielectric layer; the surface of the first dielectric layer is provided with a metal resonance layer, and a metal isolation layer is arranged between the two dielectric layers; feeder lines are arranged at the bottoms of the two dielectric layers; a first resonance piece of the metal resonance layer is located in the middle of the surface of the first dielectric layer, and a first metal column penetrating through the first resonance piece and the first dielectric layer is arranged in the middle of the first resonance piece; the second resonance piece and the third resonance piece are respectively positioned on two adjacent side parts of the surface of the first dielectric layer and are connected with the first resonance piece through a diode; one end of the second resonance piece and one end of the third resonance piece are respectively provided with metal columns. One end of the feeder line is connected with the metal column. According to the dual-frequency electromagnetic metasurface unit, array and method for enhancing underground signal coverage, energy loss and radiation loss can be reduced, and the dual-frequency electromagnetic metasurface unit, array and method have efficient electromagnetic wave reflection capacity in a low frequency range.

Description

Technical Field

[0001] The present application relates to the field of electronic countermeasure interference technology, and in particular to a dual-frequency electromagnetic metasurface unit, array and method for enhancing downhole signal coverage. Background Art

[0002] With the development of wireless communication technology, users' demand for signal transmission is gradually tending towards high speed, low latency and high reliability. However, due to the path loss of electromagnetic waves in the millimeter wave band during transmission and the easy obstruction by obstacles in complex electromagnetic environments, many non-line-of-sight signal blind spots appear, thus limiting the signal transmission of base stations. Especially in the coal mining industry, due to the long length and many branches of mine tunnels, the transmission of electromagnetic signals will be seriously affected, and the mining equipment in the tunnels will also generate electromagnetic interference, further affecting the transmission of electromagnetic signals.

[0003] In the prior art, the signal coverage area is usually increased by deploying small base stations, but this method is too expensive and the underground power supply system is prone to instability, resulting in frequent power outages in the base station, affecting the continuity of communication.

[0004] At present, there are some passive metasurfaces that can reflect, transmit and scatter electromagnetic waves, thereby increasing the transmission rate of electromagnetic signals and reducing transmission delays to a certain extent. However, since the functions of passive metasurfaces are fixed after processing and forming, they are not tunable, and cannot dynamically control electromagnetic waves, and cannot achieve arbitrary angle reflection of electromagnetic waves. In addition, crosstalk is easily generated between working frequency points, and the beam control range is also limited by design, which limits the efficiency and performance of this method in practical applications.

[0005] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0007] The purpose of the embodiments of the present disclosure is to provide a dual-frequency electromagnetic metasurface unit, array and method for enhancing downhole signal coverage, thereby overcoming one or more problems caused by the limitations and defects of related technologies at least to a certain extent.

[0008] In a first aspect, the present application provides a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage, comprising:

[0009] The dielectric layer comprises a first dielectric layer and a second dielectric layer; the surface of the first dielectric layer has a metal resonance layer; a metal isolation layer is provided between the first dielectric layer and the second dielectric layer; and a feed line is provided at the bottom of the second dielectric layer;

[0010] The metal resonance layer comprises a first resonance plate, a second resonance plate, a third resonance plate, a first diode and a second diode; the first resonance plate is located in the middle of the surface of the first dielectric layer, and the middle of the first resonance plate has a first metal column that passes through the first resonance plate and the first dielectric layer; the second resonance plate and the third resonance plate are respectively located on adjacent two sides of the surface of the first dielectric layer, and are respectively connected to the first resonance plate through the first diode and the second diode; one end of the second resonance plate has a second metal column that passes through the second resonance plate, the first dielectric layer, the metal isolation layer and the second dielectric layer; one end of the third resonance plate has a third metal column that passes through the third resonance plate, the first dielectric layer, the metal isolation layer and the second dielectric layer;

[0011] One end of the feed line is connected to the second metal column and the third metal column.

[0012] In a possible implementation, the first resonant plate has a first protrusion on a side close to the second resonant plate, the first resonant plate has a second protrusion on a side close to the third resonant plate, the second resonant plate has a third protrusion on a side close to the first resonant plate, and the third resonant plate has a fourth protrusion on a side close to the first resonant plate; the first protrusion is connected to the third protrusion via a first diode, and the first protrusion is connected to the fourth protrusion via a second diode.

[0013] In a possible implementation, the first resonant plate is quasi-rectangular, has a rectangular protrusion on a side away from the second resonant plate, and has a rectangular recess on a side away from the third resonant plate; the second resonant plate and the third resonant plate are quasi-rectangular.

[0014] In a possible implementation, the sizes of the first resonant plate, the second resonant plate, and the third resonant plate, and the intervals between the first resonant plate, the second resonant plate, and the third resonant plate are determined by analyzing the influence of the sizes and the intervals on the phase and amplitude of the electromagnetic wave; the thicknesses of the metal resonant layer and the metal isolation layer, and the size of the dielectric layer are determined by analyzing the influence of the thicknesses on the phase and amplitude of the electromagnetic wave.

[0015] In a possible implementation manner, the dielectric layer is an impregnated product material of a composite of tetrafluoroethylene and glass cloth; the metal resonance layer, the metal isolation layer, the first metal column, the second metal column and the third metal column are made of copper.

[0016] In a possible implementation, the other end of the feeder is used to connect to the positive electrode of the DC bias network, and the positive electrode of the DC bias network is connected to the second metal column and the positive electrode of the first diode through the feeder, and the positive electrode of the DC bias network is connected to the third metal column and the positive electrode of the second diode through the feeder; the cathodes of the first diode and the second diode are connected to the metal isolation layer through the first metal column, and the metal isolation layer is used to connect to the cathode of the DC bias network.

[0017] In a second aspect, the present application provides a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage, which is composed of the above-mentioned dual-frequency electromagnetic metasurface units for enhancing downhole signal coverage, and the array includes:

[0018] An array frame, comprising a plurality of fixing slots and an outer frame, wherein the outer frame is located outside the plurality of fixing slots and has a plurality of wiring interfaces;

[0019] A dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage is fixed in the fixing groove, and a feeder at the bottom is connected to the cable interface.

[0020] In a possible implementation, the dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage further includes: a digital logic control board, and the digital logic control board is connected to the metal resonance layer through the feeder line.

[0021] In a third aspect, the present application provides a method for manufacturing a dual-frequency electromagnetic metasurface for enhancing downhole signal coverage, which is used to manufacture the dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage, and the method comprises:

[0022] Obtaining dual-frequency electromagnetic metasurface unit parameters for enhanced downhole signal coverage;

[0023] According to the dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage, the preset array phase distribution at different incident angles and reflection angles is calculated to obtain the specific arrangement of the basic units in the preset array;

[0024] The preset array was simulated over the 1.8-3.8 GHz frequency band and the far-field energy was monitored at 2.1 GHz and 3.5 GHz.

[0025] In a possible implementation, the dual-frequency electromagnetic metasurface unit for establishing enhanced downhole signal coverage includes:

[0026] Establish a basic dual-frequency electromagnetic metasurface unit model for enhanced downhole signal coverage;

[0027] In the frequency band range of 1.8-3.8 GHz, the size of the metal resonance layer model and the working state of the diode model are simulated, and the influence of different sizes and different working states of the diodes on the phase and amplitude of the electromagnetic wave are analyzed to obtain a first simulation result;

[0028] In the frequency band range of 1.8-3.8 GHz, the sizes of different dielectric layer models are simulated, and the influence of the different dielectric layer sizes on the phase and amplitude of the electromagnetic wave is analyzed to obtain a second simulation result;

[0029] According to the first simulation result and the second simulation result, the dual-frequency electromagnetic metasurface unit parameters for optimal enhanced downhole signal coverage with the highest electromagnetic wave amplitude and the electromagnetic wave phase difference closest to 180° within the frequency band of 2.1 GHz and 3.5 GHz are obtained.

[0030] The technical solution provided by this application may have the following beneficial effects:

[0031] Through the above-mentioned technical scheme, the present application can optimize the structure of the metasurface unit and add diodes to achieve dynamic beam control, reduce energy loss and radiation loss, and have efficient electromagnetic wave reflection capabilities in a lower frequency range. In addition, low-frequency signals can better pass through buildings and obstructions, further enhancing the signal's penetration ability and adaptability.

[0032] The propagation direction of electromagnetic waves can be arbitrarily controlled by using metasurfaces, thus overcoming the shortcoming that traditional electromagnetic signals can only passively adapt to the wireless environment and avoiding the crosstalk problem between working frequencies. At the same time, it can achieve beam control at a larger angle at two frequencies. The incident angle of the electromagnetic wave can be adjusted according to the specific application scenario, which is more in line with engineering applications, thereby enhancing signal coverage in mines.

[0033] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0035] Figure 1A schematic diagram showing the structure of a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0036] Figure 2 A perspective schematic diagram showing a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0037] Figure 3 A schematic diagram showing the overall dimensions of a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0038] Figure 4 A schematic diagram showing the dimensions of the connection between the first metal layer and the second metal layer of a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0039] Figure 5 A schematic diagram showing the dimensions of the connection between the first metal layer and the third metal layer of a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0040] Figure 6 A schematic diagram showing the dimensions of a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0041] Figure 7 A structural diagram showing a dual-frequency electromagnetic metasurface array surface for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0042] Figure 8 A schematic diagram showing a bottom surface feeder of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0043] Fig. 9 A schematic diagram showing a process of manufacturing a dual-frequency electromagnetic metasurface for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0044] Fig.10 A schematic flow chart showing a method for determining parameters of a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0045] Fig.11 A schematic diagram showing a comparison of phase and amplitude distribution of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure;

[0046] Fig.12 A phase encoding comparison diagram at 2.1 GHz of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure is shown;

[0047] Fig.13A phase encoding comparison diagram at 3.5 GHz of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure is shown;

[0048] Fig.14 A 2.1 GHz three-dimensional long-range scattering comparison diagram of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure is shown;

[0049] Fig.15 A 3.5 GHz three-dimensional long-range scattering comparison diagram of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure is shown;

[0050] Fig.16 A 2.1 GHz one-dimensional scattering direction comparison diagram of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure is shown;

[0051] Fig.17 A 3.5 GHz one-dimensional scattering direction comparison diagram of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure is shown;

[0052] Fig.18 A comparison diagram of branch tunnel models of a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage in an exemplary embodiment of the present disclosure is shown.

[0053] Reference numerals:

[0054] 100. A dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage, 110. A metal resonance layer, 111. A first resonance plate, 112. A first through hole, 113. A second resonance plate, 1131. A second through hole, 114. A third resonance plate, 1141. A third through hole, 120. A diode, 121. A first diode, 122. A second diode, 130. A first dielectric layer, 131. A fourth through hole, 132. A fifth through hole, 133. A sixth through hole, 140. A metal isolation layer, 141. A seventh through hole, 142. A eighth through hole, 150. A second dielectric layer, 151. A ninth through hole, 152. A tenth through hole, 160. A feeder, 170. A first metal column, 180. A second metal column, 190. A third metal column;

[0055] 200. Dual-frequency electromagnetic metasurface array for enhanced downhole signal coverage. 210. Wiring interface. DETAILED DESCRIPTION

[0056] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0057] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0058] In this exemplary embodiment, a dual-frequency electromagnetic metasurface unit 100 for enhancing downhole signal coverage is first provided. Figure 1-8 As shown in FIG. 1 , the unit is composed of a metal resonant layer 110, a first dielectric layer 130, a metal isolation layer 140, a second dielectric layer 150 and a feed line 160 from top to bottom, and may include:

[0059] The dielectric layer includes a first dielectric layer 130 and a second dielectric layer 150 ; the surface of the first dielectric layer 130 has a metal resonance layer 110 ; a metal isolation layer 140 is provided between the first dielectric layer 130 and the second dielectric layer; and a feed line 160 is provided at the bottom of the second dielectric layer.

[0060] Optionally, the dielectric layer is made of a composite impregnated material of tetrafluoroethylene and glass cloth, with a relative dielectric constant of 2.65 and a dielectric loss factor of 0.001.

[0061] It should be noted that the metal isolation layer 140 can also serve as a ground layer.

[0062] The metal resonant layer 110 includes a first resonant plate 111, a second resonant plate 113, a third resonant plate 114, a first diode 121 and a second diode 122; the first resonant plate 111 is located in the middle of the surface of the first dielectric layer 130, and the middle of the first resonant plate 111 has a first metal column 170 that penetrates the first resonant plate 111 and the first dielectric layer 130; the second resonant plate 113 and the third resonant plate 114 are respectively located on the adjacent two sides of the surface of the first dielectric layer 130, and are respectively connected through the first diode 121 and the second diode 122 The first resonant plate 111 is connected; one end of the second resonant plate 113 has a second metal column 180 penetrating the second resonant plate 113, the first dielectric layer 130, the metal isolation layer 140 and the second dielectric layer 150; one end of the third resonant plate 114 has a third metal column 190 penetrating the third resonant plate 114, the first dielectric layer 130, the metal isolation layer 140 and the second dielectric layer 150; wherein, optionally, the metal resonant layer 110, the metal isolation layer 140 and the metal column are made of copper, and the diode is a PIN diode. The first diode 121 and the second diode 122 are respectively arranged in the X direction and the Y direction. One end of the feed line 160 is connected to the second metal column 180 and the third metal column 190.

[0063] The first resonant plate 111 has a first through hole 112 in the middle, the first dielectric layer 130 has a fourth through hole 131 in the middle, and the first through hole 112 is aligned with the fourth through hole 131; one end of the second resonant plate 113 has a second through hole 1131, the first dielectric layer 130 has a fifth through hole 132, the metal isolation layer 140 has a seventh through hole 141, the second dielectric layer 150 has a ninth through hole 151, and the second through hole 1131, the fifth through hole 132, the seventh through hole 141 and the ninth through hole 151 are aligned; one end of the third resonant plate 114 has a third through hole 1141, the first dielectric layer 130 has a sixth through hole 133, the metal isolation layer 140 has an eighth through hole 142, the second dielectric layer 150 has a tenth through hole 152, and the third through hole 1141, the sixth through hole 133, the eighth through hole 142 and the tenth through hole 152 are aligned.

[0064] Optionally, the second resonant plate 113 and the third resonant plate 114 above and on the left side of the metal resonant layer 110 use two identical rectangular metal strips, and introduce two metal copper columns with a radius of 0.2 mm at the upper right and lower left respectively, and at the same time, a metal through hole with a radius of 0.4 mm is etched at the same position of the middle metal isolation layer 140.

[0065] It should be noted that the working state of the diode is on or off, and the other end of the feeder 160 is used to connect to the positive electrode of the DC bias network. The positive electrode of the DC bias network is connected to the positive electrode of the first diode 121 through the feeder 160 and the second metal column 180, and the positive electrode of the DC bias network is connected to the positive electrode of the second diode 122 through the feeder 160 and the third metal column 190; the cathode of the first diode 121 and the second diode 122 is connected to the metal isolation layer 140 through the first metal column 170, and the metal isolation layer 140 is used to be connected to the cathode of the DC bias network, thereby controlling the working state of the PIN diode through the DC bias network.

[0066] Further, optionally, the first resonant plate 111 has a first protrusion on a side close to the second resonant plate 113, the first resonant plate 111 has a second protrusion on a side close to the third resonant plate 114, the second resonant plate 113 has a third protrusion on a side close to the first resonant plate 111, and the third resonant plate 114 has a fourth protrusion on a side close to the first resonant plate 111; the first protrusion is connected to the third protrusion via a first diode 121, and the first protrusion is connected to the fourth protrusion via a second diode 122.

[0067] In one embodiment, the first resonant plate 111 is quasi-rectangular, with a rectangular protrusion on the side away from the second resonant plate 113 and a rectangular depression on the side away from the third resonant plate 114, thereby changing the resonant response to the x-polarized wave and the y-polarized wave at different frequencies.

[0068] Through the above-mentioned unit, it is possible to independently manipulate the x-polarized waves and y-polarized waves at different frequencies, and through the special metal resonance layer 110 of the above-mentioned unit, phase modulation of orthogonal polarized waves at different frequencies can be achieved.

[0069] In one embodiment, the sizes of the first resonant plate 111, the second resonant plate 113 and the third resonant plate 114, and the intervals between the first resonant plate 111, the second resonant plate 113 and the third resonant plate 114 are determined by analyzing the influence of the sizes and the intervals on the phase and amplitude of the electromagnetic wave; the thicknesses of the metal resonant layer 110 and the metal isolation layer 140 and the size of the dielectric layer are determined by analyzing the influence of the thicknesses on the phase and amplitude of the electromagnetic wave.

[0070] It should be noted that if Fig.11As shown, by making the electromagnetic wave amplitude the highest and the electromagnetic wave phase difference closest to 180°, the optimal size of the metal resonance layer 110 and the dielectric layer of the dual-frequency electromagnetic metasurface unit 100 for enhancing downhole signal coverage is determined. Specifically, the amplitude and phase distribution diagram of the dual-frequency active metasurface unit when the simulated electromagnetic wave is vertically incident. We define the off state of the diode on the metasurface as "0", the on state of the diode as "1", and the numbers before and after the slash " / " represent the working states of the PIN diode in the y direction and the x direction respectively. By Fig.11 It can be seen that the reflectivity at the frequencies of 2.1 GHz and 3.5 GHz is above 0.85, and the phase difference of the switching of the four diode switch states is close to 180°. Regardless of the switching state of the PIN diode in the y direction, the switching of the PIN diode between "0" and "1" in the x direction can achieve a phase change of 180°. Similarly, regardless of the switching state of the PIN diode in the x direction, the switching of the PIN diode between "0" and "1" in the y direction can achieve a phase change of 180°, indicating that the designed active metasurface unit can independently operate at 2.1 GHz and 3.5 GHz.

[0071] Optional, such as Figure 3-6 As shown, the dimensions of the metal resonance layer 110, the metal isolation layer 140 and the dielectric layer of the dual-frequency electromagnetic metasurface unit 100 for enhancing downhole signal coverage are provided, and X1-19 are the dimensions of the metal resonance layer 110, the metal isolation layer 140 and the dielectric layer, wherein X1 is 46 mm, X2 is 24.6 mm, X3 is 34.8 mm, X4 is 1.3 mm, X5 is 22 mm, X6 is 3.6 mm, and X7 is 10 .4mm, X8 is 14mm, X9 is 4.3mm, X10 is 5.95mm, X11 is 35mm, X12 is 2mm, X13 is 0.25mm, X14 is 1.5mm, X15 is 0.85mm, X16 is 0.25mm, X17 is 1.5mm, X18 is 1.5mm, and X19 is 1mm. The thickness of the metal resonance layer 110 and the metal isolation layer 140 is 0.035mm.

[0072] This example embodiment also provides a dual-frequency electromagnetic metasurface array 200 for enhancing downhole signal coverage, see Figure 7-8 As shown, the array may include:

[0073] The array frame includes a plurality of fixing slots and an outer frame, wherein the outer frame is located outside the plurality of fixing slots and has a plurality of cable interfaces 210;

[0074] The dual-frequency electromagnetic metasurface unit 100 for enhancing downhole signal coverage is fixed in the fixing groove, and the feeder 160 at the bottom is connected to the cable interface 210 .

[0075] The number of the cable interfaces 210 corresponds to the number of fixed slots. For example, the fixed slots of the array frame are 10×10, accommodating a total of 100 units. Each unit has 2 diodes, for a total of 200 diodes. A total of 200 feed lines 160 are required, which are connected to 20 groups of cable interfaces 210 with 10 holes each, and control the diodes to switch between the on and off working states. The feed lines 160 can be DuPont lines.

[0076] In one embodiment, the dual-frequency electromagnetic metasurface array 200 for enhancing downhole signal coverage further includes: a digital logic control board connected to the metal resonance layer 110 via the feeder 160. The core of the digital logic control board is a 32-bit microcontroller based on the ARM Cortex-M core of STMicroelectronics.

[0077] Among them, the digital logic control board uses a shift register to output 225 independent control signals to drive the dual-frequency electromagnetic metasurface with enhanced downhole signal coverage to work at different frequencies.

[0078] This example embodiment also provides a method for manufacturing a dual-frequency electromagnetic metasurface for enhancing downhole signal coverage, which can be applied to a terminal device, such as a mobile phone, desktop computer, personal digital assistant, laptop computer, tablet computer, smart watch, etc. Figure 9-10 As shown in , the method may include the following steps:

[0079] Step S100: Acquire the parameters of the dual-frequency electromagnetic metasurface unit 100 for enhancing downhole signal coverage.

[0080] Step S200: According to the dual-frequency electromagnetic metasurface unit 100 for enhancing downhole signal coverage, the preset array phase distribution at different incident angles and reflection angles is calculated to obtain the specific arrangement of the basic units in the preset array.

[0081] It should be noted that if Figure 12-13 As shown, the preset array phase distribution at different incident angles and reflection angles is calculated using MATLAB computing software, thereby obtaining the specific arrangement of the basic units in the array.

[0082] Step S300: simulating a preset array within a frequency band of 1.8-3.8 GHz, and monitoring far-field energy at 2.1 GHz and 3.5 GHz.

[0083] It should be noted that if Figure 14-17 As shown, the preset array is simulated in the frequency band of 1.8-3.8 GHz using CST Microwave Studio software, and the far-field energy at 2.1 GHz and 3.5 GHz is monitored.

[0084] Depend on Figure 12-Figure 17 It can also be known that the deflection angle of the electromagnetic wave reaches the preset value, and the energy of the main lobe of the reflected wave is also concentrated in this direction.

[0085] Furthermore, the method for obtaining the parameters of the dual-frequency electromagnetic metasurface unit 100 for enhancing downhole signal coverage includes:

[0086] Step S110: Establish a basic dual-frequency electromagnetic metasurface unit 100 model for enhancing downhole signal coverage.

[0087] Step S120: within the frequency range of 1.8-3.8 GHz, simulate the size of the metal resonance layer 110 model and the working state of the diode model, analyze the influence of different sizes and different working states of the diode on the phase and amplitude of the electromagnetic wave, and obtain a first simulation result.

[0088] It should be noted that the model size of the metal resonance layer 110 and the working state of the diode model are simulated in the frequency range of 1.8-3.8 GHz by using CST Microwave Studio software to obtain the influence of the metal resonance layer 110 with different sizes and different diode working states on the phase and amplitude.

[0089] Step S130: within the frequency band of 1.8-3.8 GHz, simulate the sizes of different dielectric layer models, analyze the influence of the different dielectric layer sizes on the phase and amplitude of the electromagnetic wave, and obtain a second simulation result.

[0090] It should be noted that the simulation model of the thickness and length of the dielectric layer was simulated in the frequency band of 1.8-3.8 GHz by using CST Microwave Studio software to obtain the influence of different dielectric layer sizes on the phase and amplitude.

[0091] Step S140: According to the first simulation result and the second simulation result, obtain the dual-frequency electromagnetic metasurface unit parameters for optimal enhanced downhole signal coverage with the highest electromagnetic wave amplitude and the electromagnetic wave phase difference closest to 180° within the frequency band of 2.1 GHz and 3.5 GHz.

[0092] The dual-frequency active metasurface array of this application has the ability to fill in signal blind spots, such as Fig.18As shown in the figure, in order to verify the signal blind spot filling capability, a branch tunnel with a width of 5 meters and a height of 6 meters was established in the electromagnetic simulation software FEKO. The main tunnel is 120 meters long and the two branch tunnels are about 77 meters long. The material of the entire tunnel is defined as concrete, with a relative dielectric constant set to 4.3, a conductivity of 0.005S / m, and a magnetic permeability close to vacuum. At the beginning of the tunnel, a base station antenna radiating 2.1GHz and 3.5GHz wireless signals is deployed to radiate wireless signals to the main tunnel and hide the top of the tunnel to facilitate observation of the signal strength in the tunnel. A ray tracing model (SRT) is used to simulate the wireless propagation of electromagnetic waves. In the tunnel, we define the height of the base station antenna as 1.5mm, and the dual-frequency active metasurface is deployed in the center of the intersection of the branch tunnel. The signal strength in the tunnel under the base station only and the signal strength in the tunnel under the base station and DDCM are monitored respectively. Under the radiation of base station antennas with operating frequencies of 2.1GHz and 3.5GHz and an initial power of 100mW, the signal strengths at the intersection of the main lanes were -64.7dBm and -69.3dBm, respectively, and the signal strengths at the bottom of the lanes were -70.43dBm and -74.9dBm, respectively. However, due to the obstruction of the lane walls, the wireless signals are concentrated in the main lanes. Due to the obstruction of the lane walls, there are signal blind spots in non-line-of-sight locations such as the branch lanes on the left and right sides. The initial strength of the reflected signal can be obtained by multiplying the signal strength at the location where the metasurface is deployed in the center of the lane by the reflection efficiency of the metasurface. After the dual-frequency active metasurface is deployed in the center of the lane, the branch lanes are completely covered by wireless signals, and the signal strengths at the bottom of the branch lanes are approximately -90dBm and -93.6dBm, respectively, achieving full coverage of electromagnetic signals.

[0093] In the description of the present disclosure, 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", "clockwise", "counterclockwise" and the like 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 disclosure and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0094] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0095] In the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0096] In the present disclosure, unless otherwise expressly specified and limited, a first feature being “above” or “below” a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being “above”, “above”, and “above” a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0097] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0098] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage, characterized in that: include: The dielectric layer comprises a first dielectric layer and a second dielectric layer; The surface of the first dielectric layer has a metal resonance layer; A metal isolation layer is provided between the first dielectric layer and the second dielectric layer; a feed line is provided at the bottom of the second dielectric layer; The metal resonance layer comprises a first resonance plate, a second resonance plate, a third resonance plate, a first diode and a second diode; the first resonance plate is located in the middle of the surface of the first dielectric layer, and the middle of the first resonance plate has a first metal column that passes through the first resonance plate and the first dielectric layer; the second resonance plate and the third resonance plate are respectively located on adjacent two sides of the surface of the first dielectric layer, and are respectively connected to the first resonance plate through the first diode and the second diode; one end of the second resonance plate has a second metal column that passes through the second resonance plate, the first dielectric layer, the metal isolation layer and the second dielectric layer; one end of the third resonance plate has a third metal column that passes through the third resonance plate, the first dielectric layer, the metal isolation layer and the second dielectric layer; One end of the feed line is connected to the second metal column and the third metal column.

2. The dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage according to claim 1, characterized in that: The first resonant plate has a first protrusion on a side close to the second resonant plate, the first resonant plate has a second protrusion on a side close to the third resonant plate, the second resonant plate has a third protrusion on a side close to the first resonant plate, and the third resonant plate has a fourth protrusion on a side close to the first resonant plate; the first protrusion is connected to the third protrusion via a first diode, and the first protrusion is connected to the fourth protrusion via a second diode.

3. The dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage according to claim 2, characterized in that: The first resonant plate is quasi-rectangular, has a rectangular protrusion on a side away from the second resonant plate, and has a rectangular recess on a side away from the third resonant plate; the second resonant plate and the third resonant plate are quasi-rectangular.

4. The dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage according to claim 3, characterized in that: The sizes of the first resonant plate, the second resonant plate and the third resonant plate, and the intervals between the first resonant plate and the second resonant plate and the third resonant plate are determined by analyzing the influence of the sizes and the intervals on the phase and amplitude of the electromagnetic wave; the thickness of the metal resonant layer and the metal isolation layer and the size of the dielectric layer are determined by analyzing the influence of the thickness on the phase and amplitude of the electromagnetic wave.

5. The dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage according to claim 1, characterized in that: The dielectric layer is an impregnated composite material of tetrafluoroethylene and glass cloth; the metal resonance layer, the metal isolation layer, the first metal column, the second metal column and the third metal column are made of copper.

6. The dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage according to claim 2, characterized in that: The other end of the feeder is used to be connected to the positive electrode of the DC bias network, and the positive electrode of the DC bias network is connected to the second metal column and the positive electrode of the first diode through the feeder, and the positive electrode of the DC bias network is connected to the third metal column and the positive electrode of the second diode through the feeder; the cathode of the first diode and the second diode is connected to the metal isolation layer through the first metal column, and the metal isolation layer is used to be connected to the cathode of the DC bias network.

7. A dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage, characterized in that: The array is composed of a dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage as claimed in any one of claims 1 to 6, and the array includes: An array frame, comprising a plurality of fixing slots and an outer frame, wherein the outer frame is located outside the plurality of fixing slots and has a plurality of wiring interfaces; A dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage is fixed in the fixing groove, and a feeder at the bottom is connected to the cable interface.

8. The dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage according to claim 7, characterized in that: Also includes: The digital logic control board is connected to the metal resonance layer through the feed line.

9. A method for manufacturing a dual-frequency electromagnetic metasurface for enhancing downhole signal coverage, characterized in that: The method is used to manufacture a dual-frequency electromagnetic metasurface array for enhancing downhole signal coverage as claimed in any one of claims 7 to 8, and the method comprises: Obtaining dual-frequency electromagnetic metasurface unit parameters for enhanced downhole signal coverage; According to the dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage, the preset array phase distribution at different incident angles and reflection angles is calculated to obtain the specific arrangement of the basic units in the preset array; The preset array was simulated over the 1.8-3.8 GHz frequency band and the far-field energy was monitored at 2.1 GHz and 3.5 GHz.

10. The method for manufacturing a dual-frequency electromagnetic metasurface for enhancing downhole signal coverage according to claim 9, characterized in that: The dual-frequency electromagnetic metasurface unit for enhancing downhole signal coverage comprises: Establish a basic dual-frequency electromagnetic metasurface unit model for enhanced downhole signal coverage; In the frequency band range of 1.8-3.8 GHz, the size of the metal resonance layer model and the working state of the diode model are simulated, and the influence of different sizes and different working states of the diodes on the phase and amplitude of the electromagnetic wave are analyzed to obtain a first simulation result; In the frequency band range of 1.8-3.8 GHz, the sizes of different dielectric layer models are simulated, and the influence of the different dielectric layer sizes on the phase and amplitude of the electromagnetic wave is analyzed to obtain a second simulation result; According to the first simulation result and the second simulation result, the dual-frequency electromagnetic metasurface unit parameters for optimal enhanced downhole signal coverage with the highest electromagnetic wave amplitude and the electromagnetic wave phase difference closest to 180° within the frequency band of 2.1 GHz and 3.5 GHz are obtained.

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