Polarization insensitive wide-angle conversion unit and converter for wireless energy transmission

Abstract

The invention discloses a polarization insensitive wide-angle conversion unit for wireless energy transmission, which comprises a top dielectric plate and a bottom dielectric plate, and a metal shielding layer is arranged between the top dielectric plate and the bottom dielectric plate; an inner metal patch group and an outer metal patch group with via holes are etched on the top surface of the top layer dielectric plate, an inner metal patch group and an outer metal patch group are also etched on the bottom surface of the bottom layer dielectric plate, and the formed patch structure and the patch structure formed by the inner metal patch group and the outer metal patch group on the top surface of the top layer dielectric plate are chiral structures. The problem that performance is reduced due to polarization sensitive behaviors caused by oblique incidence is solved, no matter how the polarization angle and the incidence angle of an incident wave dynamically change, the conversion unit of the design can perform polarization matching between an electromagnetic wave receiving end and an electromagnetic wave transmitting end, and therefore under the condition that the polarization angle and the incidence angle of the incident wave are uncertain, the electromagnetic wave receiving end and the electromagnetic wave transmitting end can be matched. The transmission efficiency of energy transmission can still be ensured, and high PCR is kept.

Description

Technical Field

[0001] This invention relates to the field of microwave power transmission technology, specifically a polarization-insensitive wide-angle conversion unit and converter for wireless power transmission. Background Technology

[0002] Microwave wireless power transmission technology, as a novel wireless power transmission technology with long transmission distance and mobile power transmission characteristics, has attracted attention and research in many energy fields. In microwave wireless power transmission systems, energy is transmitted between transceivers in the form of microwaves. In order to better receive microwave energy, a converter is usually required between the transceivers to obtain a high conversion rate.

[0003] Currently, polarization converters have achieved high polarization conversion ratios (PCRs). For example, Chinese Patent Publication No. CN 210806017 U discloses a broadband reflective electromagnetic wave polarization converter based on a B-shaped metasurface. This converter comprises multiple metasurface structural units arranged periodically in the same plane. Each metasurface structural unit consists of a surface metal resonant structure, an intermediate dielectric substrate, and a bottom metal backplate. The surface metal resonant structure resembles a B-shape, consisting of two metal semi-circular rings with identical structural parameters plus a metal strip. The two metal semi-circular rings are arranged side-by-side with overlapping portions. The entire surface metal resonant structure is rotated 45 degrees counterclockwise relative to the vertical direction. This polarization converter enables vertically incident linearly polarized electromagnetic waves to generate cross-polarized waves through reflection. The operating bandwidth with a cross-polarization reflectivity greater than 0.9 can reach about 11 GHz. In the frequency range of 8.46~19.61 GHz, the polarization conversion efficiency of this polarization converter is as low as about 92%, achieving efficient polarization conversion.

[0004] Although high-efficiency converters have emerged in this field, most of them lack wide-angle and polarization-insensitive characteristics, making them unsuitable for complex microwave power transmission conditions. When the polarization angle (φ) and incident angle (θ) of the incident wave are uncertain, the transmission efficiency of the system cannot be guaranteed. Therefore, designing a low-profile, high-efficiency linear polarization converter is an urgent need in the field of microwave wireless power transmission. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, this invention proposes a polarization-insensitive wide-angle conversion unit and converter for wireless power transmission, which solves the polarization mismatch problem caused by changes in the receiver's attitude during microwave power transmission.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A polarization-insensitive wide-angle conversion unit for wireless power transmission includes a top dielectric substrate and a bottom dielectric substrate. A metal shielding layer is provided between the top dielectric substrate and the bottom dielectric substrate. The top dielectric substrate, the metal shielding layer, and the bottom dielectric substrate are all provided with vias and are connected into a whole by metal pillars passing through the vias. The top surface of the top dielectric substrate is etched with inner and outer metal patch groups with vias. The outer metal patch group includes multiple first strip-shaped metal patches distributed end-to-end around the edge of the top dielectric substrate. The first strip-shaped metal patches have identical first inscribed arc notches on both sides. The inner metal patch group is located inside the outer metal patch group and includes multiple second strip-shaped metal patches evenly distributed around the center of the top dielectric substrate at one end. The second strip-shaped metal patches have identical second inscribed arc notches on both sides. The number of first strip-shaped metal patches in the outer metal patch group is equal to the number of second strip-shaped metal patches in the inner metal patch group. Each first strip-shaped metal patch is perpendicular to its nearest second strip-shaped metal patch. The ratio of the inscribed radius of the first inscribed arc notch to the inscribed radius of the second inscribed arc notch is greater than 1 and the ratio is fixed. The bottom surface of the bottom substrate is also etched with inner and outer metal patch groups, and the patch structure formed therefrom is a chiral structure with the patch structure formed by the inner and outer metal patch groups on the top surface of the top substrate.

[0007] Furthermore, the inner metal patch group includes four second strip-shaped metal patches, which are distributed at a 90° angle to each other and have one end with a through hole facing inward around the center of the top layer dielectric plate; one end of the first strip-shaped metal patch has a through hole and the first strip-shaped metal patches are arranged end to end around the second strip-shaped metal patch, such that any second strip-shaped metal patch is perpendicular to the first strip-shaped metal patch opposite to its through hole; The structural parameters of the inner metal patch group on the bottom surface of the bottom substrate are the same as those of the second strip metal patch, and the structural parameters of the outer metal patch group are the same as those of the first strip metal patch. The metal shielding layer has four through holes corresponding to the four pairs of through holes facing the outer metal patch group at its edge, and the metal shielding layer also has four through holes corresponding to the four pairs of through holes facing the inner metal patch group at its center. Each through hole of the metal shielding layer is connected to a corresponding pair of metal patches by a metal post.

[0008] Furthermore, the inner radius of the first inscribed circular arc notch R 1 and the inscribed radius of the second inscribed circular arc notch R The ratio of 2 ranges from [3.7, 6], where the inscribed radius is... R The value of 1 ranges from 650 to 750 mm, and the inscribed radius is... RThe value of 2 ranges from 125 to 175 mm.

[0009] Furthermore, the ratio of the inner radius of the first inscribed circular arc notch to the inner radius of the second inscribed circular arc notch is 14:3.

[0010] Furthermore, the width of the second strip-shaped metal patch is the same as the width of the first strip-shaped metal patch.

[0011] Furthermore, the length of the first strip-shaped metal patch L 2 = 8 mm, width W 1 = 1 mm, the inscribed radius of the first inscribed circular notch. R 1 = 700 mm; the length of the outer metal patch L 2 = 2.8 mm, width W 2 = 1 mm, radius of the arc R 2 = 150 mm.

[0012] Furthermore, the through-hole diameter of the metal patches in the inner and outer metal patch groups... D 1 =0.8mm, the side length of the top and bottom dielectric substrates P =10mm, thickness h The value range is 0.7~0.8mm; the diameter of the via in the metal shielding layer. D 2 =1.2mm, the center distance between two adjacent vias at the edge of the metal shielding layer M 1 =8.2 mm, the center distance between two adjacent vias in the center of the metal shielding layer M 2 =1.4 mm.

[0013] Furthermore, both the top and bottom dielectric substrates are made of F4B dielectric material, which has a dielectric constant of 2.65 and a loss tangent of 0.002.

[0014] In another aspect, the present invention provides a converter comprising a metasurface on which the aforementioned conversion units are arranged in an array.

[0015] Furthermore, the array is 21 × 21.

[0016] This patent solves the problem of performance degradation caused by polarization sensitivity due to oblique incidence. Regardless of how the polarization angle and incident angle of the incident wave change dynamically, the conversion unit of this design can perform polarization matching between the electromagnetic wave receiving and transmitting ends, thereby ensuring the transmission efficiency of energy transfer and maintaining high PCR even when the polarization angle φ and incident angle θ of the incident wave are uncertain. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] Figure 2 This is a simulation result diagram of the polarization conversion ratio of the conversion unit in one embodiment of the present invention.

[0019] Figure 3 This is a current distribution diagram on the surface of the conversion unit in one embodiment of the present invention.

[0020] Figure 4 This is an IL distribution diagram of the conversion unit in one embodiment of the present invention within the polarization angle φ = 0 ~ 90°.

[0021] Figure 5 This is an IL distribution diagram of the conversion unit in one embodiment of the present invention within the polarization angle range of 0 to 60°.

[0022] Figure 6 This is a comparison diagram of the simulation diagram and the actual physical diagram of the converter in one embodiment of the present invention.

[0023] Figure 7 This is a schematic diagram of the test environment for the converter in one embodiment of the present invention.

[0024] Figure 8 This is a performance curve of the converter in measurement according to one embodiment of the present invention.

[0025] Figure 9 This is a physical construction diagram of a wireless power transmission system in one embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments disclosed in this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the disclosure of this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments disclosed in this application without creative effort are within the scope of protection of this application.

[0027] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application.

[0028] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0029] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0030] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0032] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0033] In existing technologies, the design of polarization converter unit patch structures often relies on adjusting structural parameters within a symmetrical or orthogonal framework to meet functional requirements (such as suppressing cross-polarization and increasing bandwidth). For example, this can be achieved by rotating patches, introducing multi-layer metal patches, or utilizing specific geometries (such as hexagonal or cross-shaped structures) to optimize electromagnetic wave modulation. However, these structures are typically designed for a single function (such as circular polarization conversion or beam scanning) or are limited by specific incident conditions (such as fixed polarization or incident angle), easily leading to performance trade-offs. For instance, when the polarization angle changes, the structural parameters of the antenna unit (such as microstrip line length and spacing) usually need to be optimized to adapt to different polarization angles. However, changes in structural parameters (such as microstrip line length and spacing) often reduce the effective bandwidth of the original design, thus affecting conversion efficiency. Furthermore, once the antenna unit is deployed, adjusting the structural parameters is not feasible. These reasons make it difficult for existing unit designs to simultaneously meet the requirements of wide-angle, polarization insensitivity, and high conversion efficiency.

[0034] To address the challenge of simultaneously achieving optimal performance across multiple aspects in existing technologies, this invention presents a polarization-insensitive wide-angle conversion unit for wireless power transmission. This unit is insensitive to polarization angles, exhibits strong adaptability to changes in polarization angles, and maintains high conversion efficiency without altering the unit's structural parameters. The unit design of this invention comprises a top dielectric substrate 1 and a bottom dielectric substrate 2, with a metal shielding layer 3 positioned between them. The top dielectric substrate 1, metal shielding layer 3, and bottom dielectric substrate 2 are all equipped with vias 4, and are connected as a single unit by metal pillars 5 passing through the vias 4. This conversion unit consists of three metal layers and two dielectric substrates with a thickness of h. The top metal layer is a metal pattern etched onto the top dielectric substrate 1, consisting of two inner and outer metal patch groups. Similarly, the bottom metal layer is a metal pattern etched onto the bottom dielectric substrate 2, consisting of another two inner and outer metal patch groups. The core of this solution lies in the fact that the overall patch distribution structure of the unit no longer follows the symmetry or rotational overlap characteristics of existing technologies, but innovatively adopts a chiral structure. The top surface of the top layer dielectric substrate 1 is etched with inner and outer metal patch groups with vias 4. The outer metal patch group includes multiple first strip-shaped metal patches 6 arranged end-to-end around the edge of the top layer dielectric substrate 1. The first strip-shaped metal patches 6 have identical first inscribed arc notches 61 on both sides. The inner metal patch group is located within the outer metal patch group and includes multiple second strip-shaped metal patches 7 evenly distributed around the center of the top layer dielectric substrate 1 at one end. The second strip-shaped metal patches 7 have identical second inscribed arc notches 71 on both sides. The number of first strip-shaped metal patches 6 in the outer metal patch group is equal to the number of second strip-shaped metal patches 7 in the inner metal patch group. Each first strip-shaped metal patch 6 is perpendicular to its nearest second strip-shaped metal patch 7. The ratio of the inscribed radius of the first inscribed arc notch 61 to the inscribed radius of the second inscribed arc notch 71 is greater than 1 and the ratio is fixed. The overall pattern formed by the patches on the top substrate 1 is asymmetrical, which lays the foundation for the chiral structure. The bottom surface of the bottom substrate 2 is also etched with inner and outer metal patch groups, and the patch structure formed therefrom is a chiral structure with the patch structure formed by the inner and outer metal patch groups on the top surface of the top substrate 1.

[0035] The edges of metal patches are prone to strong edge field concentration, which leads to two problems: first, the edge field can excite additional parasitic resonances, introducing unnecessary electromagnetic losses; second, the non-uniform distribution of the edge field can disrupt the continuity of the current path and reduce polarization conversion efficiency. Therefore, this design uses an inscribed circular arc notch structure on both sides of the metal patch to suppress edge field and reduce losses, and optimize impedance matching. The polarization conversion performance of the conversion unit is determined by the relative orientation of the top and bottom patch groups. The current path is connected by metal vias 4. In this design, due to the clockwise rotation relationship between the patches within the metal patch group, and the chiral structure formed by the top and bottom patch groups, the conventional mirror symmetry structure is broken, avoiding the limitations of symmetry structures such as sensitivity to polarization angle changes and bandwidth constraints. Transmission performance is related to the structural parameters of the unit. To optimize the cross-polarization transmission effect, the middle layer is a shielded metal ground with vias 4 as isolation holes. Furthermore, each pair of metal patches (the first strip metal patch 6 and its adjacent second strip metal patch 7) are rotated multiple times to form the complete structure of the dielectric layer. This ensures that the orthogonal components can be effectively and independently responded to regardless of the incident polarization direction, thus guaranteeing effective polarization adaptation without changing the structural parameters and ensuring conversion efficiency.

[0036] This solution solves the problem of performance degradation caused by polarization sensitivity due to oblique incidence. Regardless of how the polarization angle and incident angle of the incident wave change dynamically, the conversion unit of this design can perform polarization matching between the electromagnetic wave receiving and transmitting ends, thereby ensuring the transmission efficiency of energy transfer and maintaining high PCR even when the polarization angle φ and incident angle θ of the incident wave are uncertain.

[0037] like Figure 1 As shown, in a preferred embodiment, the metal patch group adopts a quadruple rotationally symmetrical orthogonal patch combination. The inner metal patch group includes four second strip-shaped metal patches 7. The second strip-shaped metal patches 7 are distributed at a 90° angle to each other, and the ends of each patch with a through hole 4 are all facing inward and surrounding the center of the top layer dielectric plate 1. One end of the first strip-shaped metal patch 6 is provided with a through hole 4, and the first strip-shaped metal patches 6 are arranged end to end around the second strip-shaped metal patches 7, such that any second strip-shaped metal patch 7 is perpendicular to the first strip-shaped metal patch 6 opposite to its through hole 4.

[0038] Accordingly, the structural parameters of the inner metal patch group on the bottom surface of the bottom substrate 2 are the same as those of the second strip metal patch 7, and the structural parameters of the outer metal patch group are the same as those of the first strip metal patch 6. That is, the distribution of the inner metal patch group on the bottom substrate 2 is obtained by rotating each of the second strip metal patches 7 of the top substrate 1 clockwise by 90 degrees around its own via 4, and the distribution of the outer metal patch group on the bottom substrate 2 is obtained by rotating each of the first strip metal patches 6 of the top substrate 1 clockwise by 90 degrees around its own via 4. The rotational characteristics of a single metal patch do not affect the overall chiral structure of the patch, so the metal patch group cannot be rotated around the center of the whole to obtain the bottom layer pattern; the same applies to the outer patch group.

[0039] Correspondingly, the metal shielding layer 3 has four vias 4 corresponding to the four pairs of metal patch groups facing outwards at its edge, and four vias 4 corresponding to the four pairs of metal patch groups facing inwards at its center. Each via 4 of the metal shielding layer 3 is connected to a corresponding pair of metal patches by a metal post 5. The top metal patch and the bottom metal patch are connected in pairs through the metal vias 4. These paired orthogonal metal patches form a closed magneto-electric coupling current path. At the same time, the shielding layer suppresses same-polarity transmission, achieving a 90° conversion of any polarization incident electromagnetic response.

[0040] The choice of a quadruple rotationally symmetric orthogonal patch combination in the above embodiments takes into account the complexity of spatial arrangement, the difficulty of equivalent circuit analysis, and the difficulty of processing and manufacturing. Experiments have verified that the quadruple structure can guarantee the comprehensive requirements of wide angle, polarization insensitivity and high conversion efficiency.

[0041] In one specific embodiment, based on the chiral layout of four-fold rotation, further optimization with specific geometric parameters can be performed to maximize conversion efficiency while maintaining polarization insensitivity. To address the problem of strong edge field concentration in electromagnetic waves of the conventional band, the inner radius of the first inscribed circular arc notch 61... R The inner radius of 1 and the second inner arc notch 71 R The ratio of 2 is fixed within the range [3.7, 6]; where the inscribed radius is... R The value of 1 ranges from 650 to 750 mm, and the inscribed radius is... R The value of 2 ranges from 125 to 175 mm, which can effectively suppress edge field loss and optimize impedance matching. A specific parameter ratio can be set to 14:3.

[0042] In verifying the performance of the conversion unit of this scheme, we selected a set of specific preferred structural parameters. The substrate uses F4B dielectric material, which has relatively stable electrical parameters, with a dielectric constant of 2.65 and a loss tangent of 0.002. To balance the electric field distribution, the widths of the metal patches are all consistent; that is, the width of the second strip metal patch 7 is the same as the width of the first strip metal patch 6. The length of the first strip metal patch 6... L 2 = 8 mm, width W 1 = 1 mm, the inscribed radius of the first inscribed circular arc notch 61 R 1 = 700 mm; the length of the outer metal patch L 2 = 2.8 mm, width W 2 = 1 mm, radius of the arc R 2 = 150 mm. The diameter of the through-hole 4 of the metal patch in the inner and outer metal patch assemblies. D 1 =0.8mm, the side length of the top dielectric substrate 1 and the bottom dielectric substrate 2 P =10mm, thickness h The value range is 0.7~0.8mm (preferably 0.75mm); the diameter of the via 4 in the metal shielding layer 3 D 2 =1.2mm, the center distance between two adjacent vias 4 at the edge of the metal shielding layer 3 M 1 =8.2 mm, the center distance between two adjacent vias 4 in the center of the metal shielding layer 3 M 2 =1.4 mm.

[0043] In the electromagnetic simulation software CST Studio Suite 2021, the conversion unit of the above embodiment was simulated and verified using periodic boundary conditions and Floquent ports. Its corresponding transmission and reflection parameters were obtained, and the corresponding polarization conversion ratio was calculated. The simulation results are as follows: Figure 2 As shown in Figure 2(a), the x-polarized incident wave is effectively converted into a y-polarized transmitted wave at 5.8 GHz, achieving the goal of cross-polarization conversion well. Figure 2(b) shows the simulation results of the conversion unit and the insertion loss (IL). The results show that the design can achieve a PCR of up to 97% at 5.8 GHz, and the IL also reaches -0.6 dB at this point, demonstrating good cross-polarization conversion performance.

[0044] In addition, to observe the conversion effect of the conversion unit of the above embodiment on electromagnetic waves, the current on the surface of the unit was extracted and plotted. At 5.8 GHz, when φ is 0° and 30° respectively, the surface current distribution of the top and bottom layers is as follows. Figure 3 As shown. The electric field on the top metal patch can be decomposed into two orthogonal components, Eix = Eicosφ and Eiy = Eisinφ. Generally, the greater the electric field strength, the stronger the surface current. Therefore, it is observed that when φ is 0° and 30°, the current on the horizontal patch is stronger than the current on the vertical patch, as shown. Figure 3 As shown in (a) and 3(c), the electromagnetic wave rotates 90° as it passes through the conversion unit. Therefore, we can observe that the current on the vertical patch is stronger than the current on the horizontal patch. This means that the incident wave has undergone a cross-polarization transition as it passes through the conversion unit, as shown in (a) and (c). Figure 3 (b) and Figure 3 As shown in (d). Therefore, based on the changes in surface current and spatial electric field, it can be confirmed that the conversion unit of the above embodiment has the function of cross-polarization conversion.

[0045] Furthermore, to discuss the polarization insensitivity and wide-angle characteristics of this design, linear polarization incident simulations were performed at different polarization angles and different incident angles. The simulation results are shown in Figures 4 and 5. In the case of polarization angles φ = 0 ~ 90°, Figures 4(a) and (b) show that the conversion element and IL remain almost unchanged. In the case of oblique incident waves, as the incident angle θ = 0 ~ 60° gradually increases, the conversion element and IL in Figures 5(a) and (b) decrease accordingly. However, in the incident angle range of -30 ~ 30°, the degradation of polarization conversion performance is not significant, indicating that the conversion performance is relatively stable under these conditions.

[0046] Therefore, it can be seen that the conversion unit of this scheme can form a unique current path and electromagnetic response mechanism when cross-polarization occurs at the transmitting and receiving ends, realizing the conversion of electromagnetic wave polarization state and the control of electromagnetic field. This conversion unit has a simple structure, low profile, high cross-polarization conversion efficiency, and can achieve high polarization conversion rate (PCR>90%), polarization insensitivity, and wide-angle stability (θ≤30°).

[0047] To achieve electromagnetic wave polarization state switching when cross-polarization occurs between the transceiver and receiver, it is essential to employ a highly efficient linear cross-polarization converter for electromagnetic field control. Based on the conversion unit of this invention, this invention also proposes a converter whose main core structure consists of arranging the aforementioned conversion units in an array on a metasurface, and fabricating a test specimen in a 21 × 21 array for experimental analysis.

[0048] Figure 6The diagram shows a comparison between the simulation and actual physical diagram of the converter. To verify the reflection and transmission coefficients of the test piece, two linearly polarized antennas were used as the transmitter and receiver, respectively, and the antenna parameters were recorded using a vector network analyzer. Furthermore, a large amount of absorbing material was used during the measurement to reduce the influence of the environment on the test results. The test environment included... Figure 7 As shown.

[0049] To measure the reflection coefficients (Rxx and Ryx), antennas were placed adjacent to each other with their polarization directions set to the same or orthogonal. Transmission coefficients (Txx and Tyx) were obtained under co-polarization and cross-polarization conditions when the antennas were located on opposite sides of the sample. PCR and IL were calculated to be 95% and -0.9 dB, respectively. PCR values ​​were measured at φ of 0°, 15°, 30°, and 45° as follows: Figure 8 As shown in (a). The comparison shows that the simulation and measurement results are generally consistent; the PCR is insensitive to changes in polarization angle, maintaining a value above 92.1% at 5.8 GHz. Meanwhile, when θ is also 0°, 15°, 30°, and 45°, Figure 8 (b) describes how the PCR gradually decreases with increasing θ. When the incident angle is in the range of 0° to 30°, the PCR remains above 90.4% at 5.8 GHz, indicating that the proposed converter has stable performance.

[0050] To verify the polarization conversion function of the design sample under wireless power transmission conditions, a wireless power transmission system was built, such as... Figure 9 As shown, in a microwave power transfer (MPT) system, two horn antennas serve as the power transmitter and receiver, respectively. Furthermore, the collected power is recorded by a power meter. Typically, when there is cross-polarization between the transmitter and receiver, the power output from the transmitter is almost impossible to collect effectively by the receiver. To address this issue and improve the power transfer efficiency (PTE) between the two ends, we embedded a designed converter sample at the transmitter, ensuring that the polarization direction of the generated electromagnetic wave is aligned with that of the receiving horn antenna. Here, the received microwave power at 5.8 GHz was measured under three different conditions. The power meter recorded a collected power of 226.5 mW under common polarization between the two antennas. However, when the polarization is mismatched (under cross-polarization conditions), the received power is close to 0. When the prepared converter sample is embedded in the receiver under cross-polarization conditions, the measured power reaches 219.7 mW, approximately 97.0% of the received power under common polarization conditions. The results demonstrate that the designed converter can be applied to polarization conversion in MPT systems and contributes to microwave power transfer.

[0051] This invention's converter, a polarization-insensitive wide-angle cross-polarization converter, solves the polarization mismatch problem caused by receiver attitude changes in microwave power transmission (MPT). As seen in the above experiments, it achieves a 95% polarization conversion rate (PCR) and -0.9 dB insertion loss (IL) at 5.8 GHz. Its four sets of rotationally symmetric orthogonal patch structures ensure polarization insensitivity, maintaining an extremely high conversion rate. The simulation and test results show that this converter maintains good polarization conversion characteristics at any polarization angle, maintaining a stable polarization conversion rate >90% within a 30° incident angle, overcoming the limitations of traditional polarization converters that are sensitive to the direction of arrival and polarization angle. MPT experimental results under transceiver polarization cross conditions show that at a transmission distance of 1.2 meters, the received power is close to 0 mW without the converter; when the converter of this invention is loaded at the receiver, the received power reaches 219.7 mW, demonstrating excellent microwave energy reception performance.

[0052] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A polarization-insensitive wide-angle conversion unit for wireless power transfer, characterized in that, It includes a top dielectric board and a bottom dielectric board, with a metal shielding layer between the top dielectric board and the bottom dielectric board. The top dielectric board, the metal shielding layer and the bottom dielectric board are all provided with vias and are connected into a whole by metal pillars passing through the vias. The top surface of the top dielectric substrate is etched with inner and outer metal patch groups with vias. The outer metal patch group includes multiple first strip-shaped metal patches distributed end-to-end around the edge of the top dielectric substrate. The first strip-shaped metal patches have identical first inscribed arc notches on both sides. The inner metal patch group is located inside the outer metal patch group and includes multiple second strip-shaped metal patches evenly distributed around the center of the top dielectric substrate at one end. The second strip-shaped metal patches have identical second inscribed arc notches on both sides. The number of first strip-shaped metal patches in the outer metal patch group is equal to the number of second strip-shaped metal patches in the inner metal patch group. Each first strip-shaped metal patch is perpendicular to its nearest second strip-shaped metal patch. The ratio of the inscribed radius of the first inscribed arc notch to the inscribed radius of the second inscribed arc notch is greater than 1 and the ratio is fixed. The bottom surface of the bottom substrate is also etched with inner and outer metal patch groups, and the patch structure formed therefrom is a chiral structure with the patch structure formed by the inner and outer metal patch groups on the top surface of the top substrate.

2. The polarization-insensitive wide-angle conversion unit for wireless power transfer according to claim 1, characterized in that: The inner metal patch group includes four second strip-shaped metal patches, which are distributed at a 90° angle to each other and have a via end facing inward around the center of the top layer dielectric plate; one end of the first strip-shaped metal patch has a via and the first strip-shaped metal patches are arranged end to end around the second strip-shaped metal patch, such that any second strip-shaped metal patch is perpendicular to the first strip-shaped metal patch opposite to its via end; The structural parameters of the inner metal patch group on the bottom surface of the bottom substrate are the same as those of the second strip metal patch, and the structural parameters of the outer metal patch group are the same as those of the first strip metal patch. The metal shielding layer has four through holes corresponding to the four pairs of through holes facing the outer metal patch group at its edge, and the metal shielding layer also has four through holes corresponding to the four pairs of through holes facing the inner metal patch group at its center. Each through hole of the metal shielding layer is connected to a corresponding pair of metal patches by a metal post.

3. The method according to claim 1 or 2, characterized in that: The inscribed radius of the first inscribed circular arc notch R The inner radius of 1 and the second inner arc notch R The ratio of 2 ranges from [3.7, 6], where the inscribed radius is... R The value of 1 ranges from 650 to 750 mm, and the inscribed radius is... R The value of 2 ranges from 125 to 175 mm.

4. The polarization-insensitive wide-angle conversion unit for wireless power transfer according to claim 3, characterized in that: The ratio of the inscribed radius of the first inscribed circular arc notch to the inscribed radius of the second inscribed circular arc notch is 14:

3.

5. The polarization-insensitive wide-angle conversion unit for wireless power transfer according to any one of claims 1 to 4, characterized in that: The width of the second strip-shaped metal patch is the same as the width of the first strip-shaped metal patch.

6. The polarization-insensitive wide-angle conversion unit for wireless power transfer according to claim 5, characterized in that: The length of the first strip-shaped metal patch L 2 = 8 mm, width W 1 = 1 mm, the inscribed radius of the first inscribed circular notch. R 1 = 700 mm; the length of the outer metal patch L 2 = 2.8 mm, width W 2 = 1 mm, radius of the arc R 2 = 150 mm.

7. The polarization-insensitive wide-angle conversion unit for wireless power transfer according to claim 6, characterized in that: The through-hole diameters of the metal patches in the inner and outer metal patch groups D 1 =0.8mm, the side length of the top and bottom dielectric substrates P =10mm, thickness h The value range is 0.7~0.8mm; the diameter of the via in the metal shielding layer. D 2 =1.2mm, the center distance between two adjacent vias at the edge of the metal shielding layer M 1 =8.2 mm, the center distance between two adjacent vias in the center of the metal shielding layer M 2 =1.4 mm.

8. The polarization-insensitive wide-angle conversion unit for wireless power transfer according to any one of claims 1 to 4, 6, and 7, characterized in that: Both the top and bottom dielectric substrates are made of F4B dielectric material, which has a dielectric constant of 2.65 and a loss tangent of 0.

002.

9. A converter, comprising a metasurface, characterized in that: The metasurface is provided with an array of conversion units as described in any one of claims 1 to 8.

10. The converter according to claim 9, characterized in that: The array is 21 × 21.

Images