Design method of negative permeability electromagnetic structure and application in wireless power transmission

Abstract

The application discloses a design method of a negative magnetic permeability electromagnetic structure and application in wireless power transmission, the negative magnetic permeability electromagnetic structure comprises a dielectric substrate, a resonance network and a resonance capacitor, the resonance network is composed of a first resonance ring, a second resonance ring and a third resonance ring printed on one side of the dielectric substrate, the resonance capacitor is composed of a capacitor C1 welded at both ends of an opening of the first resonance ring, a capacitor C2 welded at both ends of an opening of the second resonance ring and a capacitor C3 welded at both ends of an opening of the third resonance ring, and is used to improve the magnetic coupling effect between a transmitting coil and a receiving coil.The application solves the problem of system transmission coupling performance decline under the condition of long-distance wireless power transmission, improves the transmission distance and transmission efficiency of the wireless power transmission system, and the negative magnetic permeability electromagnetic structure is simple in preparation, low in cost and capable of meeting the demand of improving the efficiency of the wireless power transmission system.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission technology, specifically relating to a design method for a negative permeability electromagnetic structure and its application in wireless power transmission. Background Technology

[0002] As power transmission methods have evolved from tangible to intangible media, wireless power transmission technology is increasingly penetrating human production and daily life. Compared to traditional wired power supply, wireless power transmission technology is safer and more reliable. Resonant coupling wireless power transmission technology is widely used due to its high transmission power, minimal impact on the electromagnetic environment, and long transmission distance. However, this technology suffers from a critical coupling state; when the transmission distance exceeds this critical coupling distance, the coupling coefficient of the wireless power transmission system gradually weakens, leading to a rapid decline in transmission efficiency and deterioration in transmission performance, hindering the application of wireless power transmission technology. To address this issue, negative permeability electromagnetic structures offer a method to improve the transmission distance and efficiency of wireless power transmission systems. Negative permeability electromagnetic structures amplify evanescent waves and improve the coupling characteristics of resonant coils. They not only enable more energy from the transmitting coil to be focused on the receiving coil, improving the transmission efficiency and distance of wireless power transmission, but also offer advantages such as simple fabrication, low cost, and ease of industrial production. Therefore, designing negative permeability electromagnetic structures has profound significance for wireless power transmission. Summary of the Invention

[0003] The technical problem solved by this invention is to provide a design method for a negative permeability electromagnetic structure and its application in wireless power transmission. This effectively solves the problem of reduced transmission efficiency of wireless power transmission systems due to weakened magnetic coupling when transmitting energy over long distances. The purpose is to effectively improve the transmission efficiency and transmission distance of wireless power transmission systems.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a design method for a negative permeability electromagnetic structure, characterized in that: the negative permeability electromagnetic structure includes a dielectric substrate and a resonant network and a resonant capacitor disposed on the dielectric substrate. The resonant network is printed on one side of the dielectric substrate and consists of a first resonant ring, a second resonant ring, and a third resonant ring. The material of the resonant network is metallic copper. The first resonant ring is disposed around the second resonant ring, and the second resonant ring is disposed around the third resonant ring. The copper ring of the first resonant ring has a width of 4.8 mm, a thickness of 0.035 mm, an outer radius of 44 mm, and an opening width of 2 mm. The second resonant ring and the first resonant ring are positioned... The spacing is 1.4mm. The second resonant ring has a copper ring width of 4.8mm, a thickness of 0.035mm, and an opening width of 2mm. The third resonant ring consists of a circular copper ring and a square copper sheet. The circular copper ring has a width of 4.8mm, a thickness of 0.035mm, and an opening width of 2.4mm. The square copper sheet has a side length of 28mm and a thickness of 0.035mm. The spacing between the circular copper ring and the second resonant ring is 1.6mm. One end of the opening of the circular copper ring is connected to the square copper sheet. The resonant capacitor C1 is welded to both ends of the opening of the first resonant ring, the resonant capacitor C2 is welded to both ends of the opening of the second resonant ring, and the resonant capacitor C3 is welded to both ends of the opening of the third resonant ring.

[0005] Further specified, the dielectric substrate is square, and the material of the dielectric substrate is FR4 with a dielectric constant ε. r =4.4, thickness h=1.6mm, side length is 90mm.

[0006] Further defining the specific design process of the resonant network, the following steps are taken: Assume the plane containing the dielectric substrate is perpendicular to the horizontal plane. Using the geometric center point of the dielectric substrate as the origin, define the x-axis of the dielectric substrate as parallel to the horizontal plane and the y-axis as perpendicular to the horizontal plane, establishing a rectangular coordinate system. Facing the plane of the dielectric substrate, define the direction to the right of the center point of the dielectric substrate as the positive x-axis direction and the upward direction of the center point of the dielectric substrate as the positive y-axis direction. Set the unit length of the rectangular coordinate system to 1 mm. The center point of the first resonant ring coincides with the origin. The opening of the first resonant ring is set in the negative direction of the y-axis and is symmetrical about the y-axis. Specifically, with point O1 (0, -41.6) as the center point, along the x-axis direction, set a rectangle with a length of 2 mm and the same width as the copper ring. The second resonant ring has a rectangular opening; the center point of the second resonant ring coincides with the origin, and the opening of the second resonant ring is set in the positive direction of the y-axis and is symmetrical about the y-axis. Specifically, a rectangular opening with a length of 2mm and the same width as the copper ring is set along the x-axis with point O2(0, 35.4) as the center point; the center point of the circular copper ring of the third resonant ring coincides with the origin, and the opening of the circular copper ring of the third resonant ring is set in the fourth quadrant of the rectangular coordinate system. A rectangular opening with a length of 2.4mm and the same width as the copper ring is set along the y-axis with point O3(28.6, -3.6) as the center point. The upper end of the circular copper ring opening is connected to the right midpoint A(14, 0) of the square copper piece by a connecting line with a width of 4.8mm.

[0007] Furthermore, the resonant capacitors C1, C2, and C3 are all high-frequency surface-mount capacitors, and their capacitance values ​​are all 497pF.

[0008] The application of the negative permeability electromagnetic structure described in this invention in wireless power transmission is characterized by the following: the negative permeability electromagnetic structure is used to assemble a wireless power transmission system. Specifically, two identical negative permeability electromagnetic structures, namely negative permeability electromagnetic structure one and negative permeability electromagnetic structure two, are placed sequentially between a transmitting coil and a receiving coil that are parallel and coaxially positioned. Both negative permeability electromagnetic structures one and two are placed coaxially and parallel to the transmitting and receiving coils. The positions of the two negative permeability electromagnetic structures are determined as follows: let the transmission distance between the transmitting and receiving coils be d, and let the distance between negative permeability electromagnetic structure one (closer to the transmitting coil) and the transmitting coil be d. t The distance between the negative permeability electromagnetic structure two near the receiving coil and the receiving coil is d. r The transmitting and receiving coils are identical planar circular helical coils with a maximum radius of r. The value of d is defined as [1.5r, 4.5r]. t and d rThe values ​​of are all in the range [0, d / 2]. Within the range [1.5r, 4.5r], d is gradually increased from 1.5r to 4.5r in steps of 3r / 100. Calculate d when two negative permeability electromagnetic structures are placed in a wireless power transmission system. r =d / 3 and d t The S-parameter value of the wireless power transmission system at position d / 3 is used to calculate the transmission efficiency of the entire wireless power transmission system, which is the first column of the calculation results. Then, d is increased from 1.5r to 4.5r in steps of 3r / 100, and the transmission efficiency of the wireless power transmission system at different transmission distances is calculated without adding a negative permeability electromagnetic structure, which is the second column of the calculation results. The two columns of calculation results are grouped together according to the principle of the same transmission distance, resulting in 100 sets of data. Each set of data includes the transmission efficiency of the wireless power transmission system with and without a negative permeability electromagnetic structure at the same transmission distance. Comparing each set of data, the transmission distance corresponding to the data with the largest increase in transmission efficiency after adding the negative permeability electromagnetic structure is obtained, denoted as D. When calculating the transmission distance as D, d is increased in steps of D / 200 within the range [0, D / 2]. t Calculate d by incrementing d from 0 to D / 2. t The value of d corresponding to the maximum transmission efficiency of the wireless power transmission system when taking different values. r The value, and the specific solution process is as follows: When the transmission distance is D, when d t When d is a value within the range of values, make d r Within the range [0, D / 2], calculate d by incrementing the value from 0 to D / 2 in steps of D / 200. r By taking different values ​​for the S-parameters of the entire wireless power transmission system, and using these S-parameter values ​​to calculate the transmission efficiency of the wireless power transmission system, the maximum transmission efficiency corresponding to d is determined. r and d t Recorded as d ri and d ti Based on the above calculations, 100 sets of data are finally obtained, i.e., d. ri and d ti Given i = 1, 2, 3...100, compare the transmission efficiency of the wireless power transmission system corresponding to these 100 sets of data, and obtain the d values ​​corresponding to the two negative permeability electromagnetic structures when the wireless power transmission system performs optimally. t and d r value.

[0009] Compared to traditional wireless power transmission systems, this invention offers the following advantages and benefits: It provides a feasible wireless power transmission method to improve the transmission characteristics of wireless power transmission systems. By loading a negative permeability electromagnetic structure, the distribution of the 13.56MHz alternating magnetic field radiated by the transmitting coil of the wireless power transmission system is altered and the magnetic field is focused. This allows the receiving coil of the wireless power transmission system to receive more magnetic field energy radiated by the transmitting coil over long distances, thereby increasing the magnetic field strength of the receiving coil, enhancing the magnetic coupling between the two coils, and significantly improving the system's transmission efficiency and transmission distance. The negative permeability electromagnetic structure of this invention can be manufactured using PCB printing technology, resulting in a small size, thin thickness, simple process, low cost, and suitability for industrial production. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the negative permeability electromagnetic structure of the present invention;

[0011] Figure 2 This is a graph showing the S-parameters of the negative permeability electromagnetic structure of this invention.

[0012] Figure 3 These are the real and imaginary permeability curves of the negative permeability electromagnetic structure of this invention.

[0013] Figure 4 This is the equivalent circuit diagram of the negative permeability electromagnetic structure of the present invention;

[0014] Figure 5 This is a schematic diagram of the electromagnetic structure with two negative permeabilities of the present invention in a wireless power transmission system;

[0015] Figure 6 This is a comparative analysis chart of the transmission efficiency data of the present invention and existing conventional systems at different transmission distances;

[0016] Figure 7 This is a data graph showing the transmission efficiency of the system when the two negative permeability electromagnetic structures of this invention are located at different positions.

[0017] In the diagram: 101, First resonant ring; 102, Second resonant ring; 103, Third resonant ring; 104, Dielectric substrate; C1, Resonant capacitor C1; C2, Resonant capacitor C2; C3, Resonant capacitor C3; 1, Negative permeability electromagnetic structure one; 2, Negative permeability electromagnetic structure two; 3, Transmitting coil; 4, Receiving coil. Detailed Implementation

[0018] To make the content and advantages of the technical solution of the present invention clearer, the following describes in further detail, with reference to the accompanying drawings, a method for designing a negative permeability electromagnetic structure for wireless power transmission.

[0019] The core of this invention is the design of a negative permeability electromagnetic structure. Designing such a structure requires calculating the dimensions of the dielectric substrate, the equivalent permeability of the structure, and its performance in improving the transmission efficiency of the wireless power transmission system. This allows for faster and more accurate identification of a suitable negative permeability electromagnetic structure for a specific frequency in simulation experiments. Because the electromagnetic structure has a high subwavelength scale, theoretical calculations are necessary during its design.

[0020] The dimensions of the dielectric substrate are L×L, and the ratio of the wavelength to the side length of the dielectric substrate should satisfy the following:

[0021]

[0022] In the formula, λ is the wavelength of the negative permeability electromagnetic structure, c is the speed of light, f is the resonant frequency of the negative permeability electromagnetic structure, and L is the side length of the dielectric substrate.

[0023] The equivalent permeability of a negative permeability electromagnetic structure is:

[0024]

[0025]

[0026] μ=nz (4)

[0027] In the formula, n is the refractive index of the negative permeability electromagnetic structure, k = 1 / λ is the wave number, d is the equivalent thickness of the negative permeability electromagnetic structure, and S 11 S 21 The reflection and projection parameters of the negative permeability electromagnetic structure are obtained through HFSS electromagnetic simulation software. z is the wave impedance of the negative permeability electromagnetic structure, and μ is the equivalent permeability of the negative permeability electromagnetic structure.

[0028] Once the dimensions of the negative permeability electromagnetic structure are determined, it is applied to a wireless power transfer system. Both the transmitting and receiving coils are driven by lumped ports, enabling energy transfer from the transmitting coil to the receiving coil. When the negative permeability electromagnetic structure is used in a wireless power transfer system, the system's transmission efficiency is:

[0029]

[0030] In the formula, η is the transmission efficiency of the wireless power transmission system, and S 11 S 21 The reflection and projection parameters of the negative permeability electromagnetic structure were obtained using HFSS electromagnetic simulation software.

[0031] like Figure 1As shown, a design method for a negative permeability electromagnetic structure for wireless power transmission is disclosed. The negative permeability electromagnetic structure consists of a dielectric substrate, a resonant network, and a resonant capacitor. The dielectric substrate 104 is square and made of FR4 with a dielectric constant ε. r=4.4, thickness h = 1.6mm, side length 90mm; the resonant network is printed on one side of the dielectric substrate 104; the design and dimensions of the resonant network meet the following requirements: the resonant network consists of a first resonant ring 101, a second resonant ring 102, and a third resonant ring 103, and the material of the resonant network is metallic copper; the first resonant ring 101 is disposed around the second resonant ring 102, and the second resonant ring 102 is disposed around the third resonant ring 103; the copper ring of the first resonant ring 101 has a width of 4.8mm, a thickness of 0.035mm, an outer radius of 44mm, and an opening width of 2mm; the distance between the second resonant ring 102 and the first resonant ring 101 is 1.4m. The second resonant ring 102 has a copper ring width of 4.8 mm, a thickness of 0.035 mm, and an opening width of 2 mm. The third resonant ring 103 consists of a circular copper ring and a square copper sheet. The circular copper ring has a width of 4.8 mm, a thickness of 0.035 mm, and an opening width of 2.4 mm. The square copper sheet has a side length of 28 mm and a thickness of 0.035 mm. The distance between the circular copper ring and the second resonant ring 102 is 1.6 mm. One end of the opening of the circular copper ring is connected to the square copper sheet. Assuming the plane of the dielectric substrate 104 is perpendicular to the horizontal plane, and taking the geometric center point of the dielectric substrate 104 as the origin, the x-axis on the dielectric substrate 104 is defined as parallel to the horizontal plane. The y-axis on the dielectric substrate 104 is perpendicular to the horizontal plane, establishing a rectangular coordinate system. Facing the plane of the dielectric substrate 104, the direction to the right of the center point of the dielectric substrate 104 is set as the positive x-axis, and the direction upward from the center point of the dielectric substrate 104 is set as the positive y-axis. The unit length of the rectangular coordinate system is set to 1 mm. The center point of the first resonant ring 101 coincides with the origin. The opening of the first resonant ring 101 is set in the negative direction of the y-axis and is symmetrical about the y-axis. Specifically, a rectangular opening with a length of 2 mm and the same width as the copper ring is set along the x-axis with point O1 (0, -41.6) as the center point. The center point of the second resonant ring 102 coincides with the origin. The opening of 02 is set in the positive direction of the y-axis and is symmetrical about the y-axis. Specifically, a rectangular opening with a length of 2mm and the same width as the copper ring is set along the x-axis with point O2(0, 35.4) as the center point. The center point of the circular copper ring of the third resonant ring 103, the center point of the square copper sheet, and the origin coincide. The opening of the circular copper ring of the third resonant ring 103 is set in the fourth quadrant of the rectangular coordinate system. A rectangular opening with a length of 2.4mm and the same width as the copper ring is set along the y-axis with point O3(28.6, -3.6) as the center point. The upper end of the opening of the circular copper ring is connected to the right midpoint A(14, 0) of the square copper sheet by a connecting line with a width of 4.8mm; the resonant capacitors include resonant capacitor C1, resonant capacitor C2, and resonant capacitor C3; all three resonant capacitors C1, C2, and C3 are high-frequency surface-mount capacitors, and each has a capacitance of 497pF; resonant capacitor C1 is welded to both ends of the opening of the first resonant ring, resonant capacitor C2 is welded to both ends of the opening of the second resonant ring, and resonant capacitor C3 is welded to both ends of the opening of the third resonant ring.

[0032] Figure 2 This is a graph showing the S-parameters of the negative permeability electromagnetic structure-1. As can be seen from the graph, the S-parameters of the negative permeability electromagnetic structure-1... 11 and S 21 Resonance occurs at a frequency of 13.56MHz.

[0033] Figure 3 The graph shows the real and imaginary part curves of the equivalent permeability of the negative permeability electromagnetic structure. As can be seen from the graph, the real part of the equivalent permeability of the negative permeability electromagnetic structure resonates at 13.56MHz. The permeability after the resonant frequency point is negative, exhibiting negative permeability characteristics. This negative permeability characteristic causes a magnetic focusing effect when the alternating magnetic field generated by the transmitting coil 3 of the wireless power transmission system passes through the electromagnetic structure, thereby achieving artificial control of the magnetic field. More evanescent waves are focused at the receiving coil 4 of the wireless power transmission system, thus improving the efficiency of the wireless power transmission system.

[0034] Figure 4 This is the equivalent circuit diagram of a negative permeability electromagnetic structure. Due to the influence of a magnetic field, resonance occurs. The negative permeability electromagnetic structure can be equivalently represented as an RLC resonant circuit including a resonant network, a resonant capacitor, and a dielectric substrate 104. In the diagram, L1, L2, and L3 are the inductances of the first resonant ring 101, the second resonant ring 102, and the third resonant ring 103 of the resonant network, respectively. R1, R2, and R3 are the internal resistances of the first resonant ring 101, the second resonant ring 102, and the third resonant ring 103 of the resonant network. C 11 C 22 and C 33 The parasitic capacitances of the first resonant ring 101, the second resonant ring 102, and the third resonant ring 103 of the resonant network are shown. Resonant capacitors C1, C2, and C3 are all high-frequency surface-mount resonant capacitors. gap12 C is the gap capacitance between the first resonant ring 101 and the second resonant ring 102. gap13 C is the gap capacitance between the first resonant ring 101 and the third resonant ring 103. gap23 It is the gap capacitance between the second resonant ring 102 and the third resonant ring 103.

[0035] Figure 5This is a schematic diagram illustrating the application of two identical negative permeability electromagnetic structures in a wireless power transmission system. The transmitting coil 3, negative permeability electromagnetic structure one 1, negative permeability electromagnetic structure two 2, and receiving coil 4 are arranged parallel to each other and coaxially. The transmission distance between the transmitting coil 3 and the receiving coil 4 is d, and the distance between the negative permeability electromagnetic structure one 1 (closer to the transmitting coil 3) and the transmitting coil 3 is also d. t The distance between the negative permeability electromagnetic structure 2 near the receiving coil 4 and the receiving coil 4 is d. r The transmitting coil 3 and the receiving coil 4 have identical structures, both being planar circular spiral coils made of 3 turns of copper wire with a diameter of 3 mm. The maximum radius r of both coils is 42 mm, and there is no direct electrical connection between the transmitting coil 3 and the receiving coil 4. The negative permeability electromagnetic structure 1 and the negative permeability electromagnetic structure 2 have identical structures.

[0036] The method for determining the positions of the two negative permeability electromagnetic structures is as follows: Let the transmission distance between the transmitting coil 3 and the receiving coil 4 be d, and the distance between the negative permeability electromagnetic structure -1 near the transmitting coil 3 and the transmitting coil 3 be d. t The distance between the negative permeability electromagnetic structure 2 near the receiving coil 4 and the receiving coil 4 is d. r The transmitting coil 3 and the receiving coil 4 are identical planar circular helical coils with a maximum radius of r. The value of d is defined as [1.5r, 4.5r]. t and d r The values ​​of are all in the range [0, d / 2]. Within the range [1.5r, 4.5r], d is gradually increased from 1.5r to 4.5r in steps of 3r / 100. Calculate d when two negative permeability electromagnetic structures are placed in a wireless power transmission system. r =d / 3 and d t The S-parameter value of the system at position d / 3 is used to calculate the transmission efficiency of the entire wireless power transmission system, which is the first column of the calculation results. Then, d is increased from 1.5r to 4.5r in steps of 3r / 100, and the transmission efficiency of the wireless power transmission system at different transmission distances is calculated without adding a negative permeability electromagnetic structure, which is the second column of the calculation results. These two columns of calculation results are grouped together according to the same transmission distance, resulting in 100 sets of data. Each set of data includes the transmission efficiency of the wireless power transmission system with and without a negative permeability electromagnetic structure at the same transmission distance. Comparing each set of data, the transmission distance corresponding to the data with the largest increase in transmission efficiency after adding the negative permeability electromagnetic structure is obtained, denoted as D. Further, when calculating the transmission distance as D, d is increased in steps of D / 200 within the range [0, D / 2]. tCalculate d by incrementing d from 0 to D / 2. t The value of d corresponding to the maximum transmission efficiency of the wireless power transmission system when taking different values. r The value, and the specific solution process is as follows: When the transmission distance is D, when d t When d is a value within the range of values, make d r Within the range [0, D / 2], calculate d by incrementing the value from 0 to D / 2 in steps of D / 200. r By taking different values ​​for the S-parameters of the entire wireless power transmission system, and using the S-parameters to calculate the transmission efficiency of the wireless power transmission system, the maximum transmission efficiency corresponding to d is determined. r and d t Recorded as d ri and d ti Based on the above calculations, 100 sets of data can be obtained, i.e., d. ri and d ti For i = 1, 2, 3...100, by comparing the transmission efficiency of the wireless power transmission system corresponding to these 100 sets of data, we can obtain the d values ​​corresponding to the two negative permeability electromagnetic structures when the wireless power transmission system performs optimally. t and d r value.

[0037] Figure 6 It refers to the addition of d at different transmission distances d in the wireless power transmission system. r =d / 3, d t The transmission efficiency diagram of two identical negative permeability electromagnetic structures at position d / 3 shows that, compared with existing traditional wireless power transmission systems, this invention not only significantly improves the transmission efficiency of the wireless power transmission system, but also increases the transmission distance of the wireless power transmission system.

[0038] Figure 7 This is a graph showing the transmission efficiency of two identical negative permeability electromagnetic structures located at different positions in a wireless power transmission system when the transmission distance d is 120mm. The graph shows that when the two negative permeability electromagnetic structures are located at d... r =30mm, d t When the distance is 50mm, compared with the existing conventional wireless power transmission system, the transmission efficiency of the wireless power transmission system of the present invention is increased from 14.7% to 85.6%, at which point the transmission efficiency performance of the wireless power transmission system is optimal.

[0039] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A design method for electromagnetic structures with negative permeability, characterized in that: The negative permeability electromagnetic structure includes a dielectric substrate and a resonant network and a resonant capacitor disposed on the dielectric substrate. The resonant network is printed on one side of the dielectric substrate and consists of a first resonant ring, a second resonant ring, and a third resonant ring. The material of the resonant network is metallic copper. The first resonant ring is disposed around the second resonant ring, and the second resonant ring is disposed around the third resonant ring. The copper ring of the first resonant ring has a width of 4.8 mm, a thickness of 0.035 mm, an outer radius of 44 mm, and an opening width of 2 mm. The distance between the second resonant ring and the first resonant ring is 1.4 mm. The copper ring of the second resonant ring has a width of 4 mm. The first resonant ring has a diameter of 4.8 mm, a thickness of 0.035 mm, and an opening width of 2 mm. The second resonant ring is composed of a circular copper ring and a square copper sheet. The circular copper ring has a width of 4.8 mm, a thickness of 0.035 mm, and an opening width of 2.4 mm. The square copper sheet has a side length of 28 mm and a thickness of 0.035 mm. The distance between the circular copper ring and the second resonant ring is 1.6 mm. One end of the opening of the circular copper ring is connected to the square copper sheet. The resonant capacitor C1 is welded to both ends of the opening of the first resonant ring, the resonant capacitor C2 is welded to both ends of the opening of the second resonant ring, and the resonant capacitor C3 is welded to both ends of the opening of the third resonant ring.

2. The design method for a negative permeability electromagnetic structure according to claim 1, characterized in that: The dielectric substrate is square, and the material of the dielectric substrate is FR4 with a dielectric constant of [missing value]. ε r =4.4, thickness h =1.6mm, side length is 90mm.

3. The design method for a negative permeability electromagnetic structure according to claim 1, characterized in that: The specific design process of the resonant network is as follows: Assume the plane containing the dielectric substrate is perpendicular to the horizontal plane, and define the plane on the dielectric substrate as the origin. x The axis is parallel to the horizontal plane and on the dielectric substrate. y Establish a rectangular coordinate system with the axis perpendicular to the horizontal plane; Facing the plane of the dielectric substrate, the direction to the right of the center point of the dielectric substrate is set as x The positive axis direction, with the center point of the dielectric substrate pointing upwards, is set as follows: y In the positive direction of the axis, let the unit length of the rectangular coordinate system be 1mm; the center point of the first resonant ring coincides with the origin, and the opening of the first resonant ring is set at... y The negative direction of the axis and about y Axisymmetric, specifically: with point O1 (0, -41.6) as the center point along... x In the axial direction, a rectangular opening with a length of 2mm and the same width as the copper ring is provided; the center point of the second resonant ring coincides with the origin, and the opening of the second resonant ring is set at... y The positive direction of the axis and about y Axisymmetric, specifically: with point O2 (0, 35.4) as the center point along... x Along the axial direction, a rectangular opening with a length of 2mm and the same width as the copper ring is set; the center point of the circular copper ring of the third resonant ring, the center point of the square copper sheet, and the origin coincide; the opening of the circular copper ring of the third resonant ring is set in the fourth quadrant of the rectangular coordinate system, with point O3 (28.6, -3.6) as the center point along... y A rectangular opening with a length of 2.4 mm and the same width as the copper ring is set in the axial direction. The upper end of the circular copper ring opening is connected to the right midpoint A (14, 0) of the square copper sheet by a connecting line with a width of 4.8 mm.

4. The design method for a negative permeability electromagnetic structure according to claim 1, characterized in that: The resonant capacitors C1, C2, and C3 are all high-frequency surface-mount capacitors, and their capacitance values ​​are all 497pF.

5. The application of the negative permeability electromagnetic structure according to any one of claims 1-4 in wireless power transmission, characterized in that: The negative permeability electromagnetic structure is used to assemble a wireless power transmission system. The specific process is as follows: Two identical negative permeability electromagnetic structures, namely negative permeability electromagnetic structure one and negative permeability electromagnetic structure two, are placed sequentially between a transmitting coil and a receiving coil that are parallel and coaxially positioned opposite each other. Both negative permeability electromagnetic structures one and two are placed coaxially and parallel to the transmitting and receiving coils. The positions of the two negative permeability electromagnetic structures are determined as follows: Let the transmission distance between the transmitting and receiving coils be... d The distance between the negative permeability electromagnetic structure near the transmitting coil and the transmitting coil is... d t The distance between the negative permeability electromagnetic structure two near the receiving coil and the receiving coil is... d r The transmitting and receiving coils are identical planar circular helical coils, with a maximum radius of [missing information]. r ,definition d The value range is [1.5]. r 4.5 r ], d t and d r The range of values ​​for all values ​​is [0, ...]. d / 2]; in [1.5 r 4.5 r Within the range of values ​​of ], make d According to 3 r The step size is 1.5 / 100. r Gradually increasing to 4.5 r Calculate when two negative permeability electromagnetic structures are placed in a wireless power transmission system. d r = d / 3 and d t = d / 3 Location-based wireless power transfer system S Parameter values, using S The parameter values ​​are used to calculate the transmission efficiency of the entire wireless power transmission system, which is the first column of the calculation results. Then again d According to 3 r The step size is 1.5 / 100. r Gradually increasing to 4.5 r The transmission efficiency of the wireless power transmission system at different transmission distances without the addition of a negative permeability electromagnetic structure is calculated as the second column of the results. These two columns of results are grouped together according to the same transmission distance, resulting in 100 sets of data. Each set contains the transmission efficiency of the wireless power transmission system with and without the negative permeability electromagnetic structure at the same transmission distance. By comparing each set of data, the transmission distance corresponding to the data with the largest increase in transmission efficiency after adding the negative permeability electromagnetic structure is obtained, denoted as . D ; Calculate the transmission distance as D At that time, in [0, D Within the range of values ​​of / 2], according to D A step size of / 200 makes d t Gradually increasing from 0 to D / 2, calculate d t The wireless power transmission system achieves maximum transmission efficiency when different values ​​are selected. d r The value, and the specific solution process are as follows: At a transmission distance of... D At that time, d t When the value is a certain value within the range, make d r In [0, D Within the range of values ​​of / 2], according to D The step size of / 200 gradually increases from 0 to... D / 2, calculate d r The entire wireless power transmission system when taking different values S Parameter values, using S The parameter values ​​are used to calculate the transmission efficiency of the wireless power transmission system, and the value corresponding to the maximum transmission efficiency of the wireless power transmission system is then calculated. d r and d t Recorded as d ri and d ti Based on the above calculations, a total of 100 sets of data were obtained, namely... d ri and d ti Given i = 1, 2, 3...100, compare the transmission efficiency of the wireless power transmission system corresponding to these 100 sets of data, and obtain the corresponding values ​​of the two negative permeability electromagnetic structures when the wireless power transmission system performs optimally. d t and d r value.

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