A tri-band artificial magnetic conductor and wearable device

Abstract

The utility model discloses a three frequency band artificial magnetic conductor and wearable equipment, include: base, the artificial magnetic conductor array of the first side surface of base and the ground plane of the second side surface of base, the artificial magnetic conductor array includes M X N periodic distribution artificial magnetic conductor unit, the artificial magnetic conductor unit includes: quadrilateral radiation patch, four T -shaped grooves located quadrilateral radiation patch edge and the similar gyro -dagger shape radiation patch with etching arc -shaped groove in quadrilateral radiation patch middle part, T -shaped groove includes first side and second side, first side parallels the edge of quadrilateral radiation patch, and the second side is perpendicular to the edge of quadrilateral radiation patch, and the first side of four T -shaped grooves surrounds the similar gyro -dagger shape radiation patch, the three frequency band artificial magnetic conductor provided by the utility model can cover wider band range, satisfies the compatibility and frequency cooperativity of multi -frequency section communication system, promotes the security and reliability of wearable equipment.

Description

Technical Field

[0001] This utility model relates to the field of artificial magnetic conductor technology, and in particular to a three-band artificial magnetic conductor and wearable device. Background Technology

[0002] With the rapid development of human body communication systems such as the Internet of Things (IoT) and wireless body area networks (BWA), wearable devices have become important terminals in fields such as health monitoring, medical assistance, and personal communication. Wearable antennas operating in the 2.45GHz, 5.8GHz, and 7GHz frequency bands are widely used in various communication protocols and emerging wireless application scenarios. The 2.45GHz and 5.8GHz bands are commonly used for wireless communications such as Bluetooth to collect, upload, and interact with health data; while the 7GHz band, as an extension band for Wi-Fi and a candidate band for future 6G communication, has greater bandwidth and lower latency, making it suitable for high-data-rate, high-reliability scenarios such as Fixed Wireless Access (FWA), smart manufacturing, and sensor communication convergence. However, because wearable antennas need to be attached to the human body for extended periods, the electromagnetic radiation they generate during operation may pose a potential threat to user health. At the same time, the strong electromagnetic coupling between the antenna and human tissue can easily lead to reduced communication efficiency, specific absorption rate (SAR) exceeding safe limits, and performance instability after antenna bending.

[0003] In existing technologies, the use of artificial magnetic conductors (AMC) structures as antenna backplanes has been proven to effectively improve antenna radiation directivity, increase forward gain, and suppress back radiation, thereby reducing SAR values ​​and improving communication reliability. However, existing AMC structures still have many shortcomings when applied to multi-frequency wearable antennas, such as limited bandwidth coverage, poor structural flexibility, sensitivity to electromagnetic waves with different polarizations or changes in electromagnetic wave incident angles, and weak adaptability to near-human environments. Furthermore, the structural design under multi-frequency coexistence conditions is complex, and performance verification under dynamic bending conditions is lacking, making it difficult to meet the comprehensive requirements of wearable devices for thinness, flexibility, and stable communication performance.

[0004] In multi-frequency wearable antenna systems, especially for Wireless Body Area Network (WBAN) communication terminals targeting the 2.45GHz, 5.8GHz, and 7GHz bands, the antenna needs to be worn close to the human body and often undergoes rotation, tilting, or attitude changes during use. These factors not only affect the antenna's radiation directivity and impedance matching but may also cause changes in the incident angle and polarization state of electromagnetic waves, leading to system performance fluctuations, enhanced back radiation, and even communication interruptions. Utility Model Content

[0005] This invention provides a three-band artificial magnetic conductor and wearable device. By using a quadrilateral radiating patch and a T-shaped groove, the resonant positions of the first and third resonant frequencies can be effectively adjusted. By adding a boomerang-shaped radiating patch with etched arc grooves, the resonant position of the second resonant frequency can be effectively adjusted, achieving zero-phase reflection near the second resonant frequency. Through the triple resonance synergistic design, a three-frequency in-phase reflection characteristic is formed, and it can effectively cover a wider frequency band, meeting the application requirements of multi-frequency wearable communication systems.

[0006] According to a first aspect of the present invention, a three-band artificial magnetic conductor is provided, comprising: a substrate, an array of artificial magnetic conductors located on a first side surface of the substrate, and a ground plane located on a second side surface of the substrate;

[0007] The artificial magnetic conductor array comprises M×N periodically distributed artificial magnetic conductor units;

[0008] The artificial magnetic conductor unit includes: a quadrilateral radiating patch, four T-shaped grooves located at the edges of the quadrilateral radiating patch, and a boomerang-shaped radiating patch with etched arc grooves located in the middle of the quadrilateral radiating patch.

[0009] The T-slot includes a first side and a second side. The first side is parallel to the edge of the quadrilateral radiating patch, and the second side is perpendicular to the edge of the quadrilateral radiating patch. The first sides of the four T-slots surround the boomerang-shaped radiating patch.

[0010] The boomerang-shaped radiation patch includes: a first part, a second part, a third part, and a fourth part;

[0011] The first part is a fan-shaped structure with three arc-shaped edges. The fan-shaped structure includes a first arc-shaped groove and a second arc-shaped groove. Both the first arc-shaped groove and the second arc-shaped groove are groove structures with one end open. The center of all the first arc-shaped grooves and the second arc-shaped grooves is the center of the boomerang-shaped radial patch.

[0012] The first portion is rotated 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the second portion; the second portion is rotated 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the third portion; and the third portion is rotated 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the fourth portion; or the first portion is rotated 90° clockwise around the center of the boomerang-shaped radiating patch to coincide with the fourth portion; and the fourth portion is rotated 90° clockwise around the center of the boomerang-shaped radiating patch to coincide with the third portion. The three parts overlap, with the third part rotating 90° clockwise around the center of the boomerang-shaped radiating patch to overlap with the second part; the first and third resonant frequencies are introduced by the T-shaped groove, and the widths of the first and second arc-shaped grooves or the radius of the boomerang-shaped radiating patch are different, resulting in different resonant positions of the second resonant frequency; wherein the first and second side surfaces are arranged opposite to each other; the frequency bands of the first, second, and third resonant frequencies increase sequentially; M and N are both positive integers greater than or equal to 2.

[0013] Optionally, the artificial magnetic conductor unit further includes: a circular groove;

[0014] The circular groove is located within the area enclosed by the first sides of the four T-shaped grooves, and the boomerang-shaped radiating patch is disposed within the circular groove; the center of the circular groove coincides with the center point of the boomerang-shaped radiating patch.

[0015] Optionally, the outer diameter of the circular groove is 8.3mm-8.5mm.

[0016] Optionally, the groove length of the first side is 14mm-15mm, and the groove width of the first side is 0.8mm-1.0mm.

[0017] Optionally, the groove length of the second side is 2.2mm-2.6mm, and the groove width of the second side is 0.8mm-1.2mm.

[0018] Optionally, the radius of the boomerang-shaped radiating patch is 7.8mm-8.0mm.

[0019] Optionally, the widths of the first arc-shaped groove and the second arc-shaped groove are 0.3mm-0.9mm.

[0020] Optionally, the edge length of the ground plane is the same as the edge length of the substrate, and the edge length of the substrate is greater than the edge length of the artificial magnetic conductor array.

[0021] Optionally, the materials of the ground plane and the artificial magnetic conductor array both include conductive cloth; the material of the substrate is felt.

[0022] According to a second aspect of the present invention, a wearable device is provided, comprising a three-band artificial magnetic conductor as described in any of the first aspects of the present invention.

[0023] This utility model discloses a three-band artificial magnetic conductor and a wearable device, comprising: a substrate, an artificial magnetic conductor array located on a first side surface of the substrate, and a ground plane located on a second side surface of the substrate; the artificial magnetic conductor array comprises M×N periodically distributed artificial magnetic conductor units; each artificial magnetic conductor unit comprises: a quadrilateral radiating patch, four T-shaped grooves located at the edges of the quadrilateral radiating patch, and a boomerang-shaped radiating patch with etched arc-shaped grooves located in the middle of the quadrilateral radiating patch; the T-shaped grooves comprise a first side and a second side, the first side being parallel to the edge of the quadrilateral radiating patch, and the second side being perpendicular to the edge of the quadrilateral radiating patch, the first sides of the four T-shaped grooves surrounding the boomerang-shaped radiating patch; the boomerang-shaped radiating patch comprises: a first part, a second part, a third part, and a fourth part; the first part is a fan-shaped structure with three arc-shaped edges, the fan-shaped structure comprising a first arc-shaped groove and a second arc-shaped groove, both the first and second arc-shaped grooves being groove structures with one open end, and the centers of all the first and second arc-shaped grooves being... The center of the boomerang-shaped radiating patch; the first part rotates 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the second part, the second part rotates 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the third part, and the third part rotates 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the fourth part; or the first part rotates 90° clockwise around the center of the boomerang-shaped radiating patch to coincide with the fourth part, the fourth part rotates 90° clockwise around the center of the boomerang-shaped radiating patch to coincide with the third part, and the third part rotates 90° clockwise around the center of the boomerang-shaped radiating patch to coincide with the second part; the first resonant frequency and the third resonant frequency are introduced by a T-shaped groove, the width of the first arc groove and the second arc groove or the radius of the boomerang-shaped radiating patch are different, and the resonant position of the second resonant frequency is different; wherein, the first side surface and the second side surface are arranged opposite to each other; the frequency bands of the first resonant frequency, the second resonant frequency and the third resonant frequency increase sequentially; M and N are both positive integers greater than or equal to 2. This invention provides a three-band artificial magnetic conductor and wearable device. By using a quadrilateral radiating patch and a T-shaped groove, the resonant positions of the first and third resonant frequencies can be effectively adjusted. By adding a boomerang-shaped radiating patch with etched arc grooves, the resonant position of the second resonant frequency can be effectively adjusted, achieving zero-phase reflection near the second resonant frequency. Through the triple resonance synergistic design, a three-frequency in-phase reflection characteristic is formed, and it can effectively cover a wider range of resonant frequencies, meeting the application requirements of multi-frequency wearable communication systems.

[0024] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a three-band artificial magnetic conductor provided in an embodiment of the present invention;

[0027] Figure 2 This is a top view of an artificial magnetic conductor array provided in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of an artificial magnetic conductor unit provided in an embodiment of the present invention;

[0029] Figure 4 This is a curve showing the reflection coefficient of a three-band artificial magnetic conductor as a function of frequency, provided in this embodiment of the present invention.

[0030] Figure 5 This is a reflection phase curve diagram of a three-band artificial magnetic conductor provided in this embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the boomerang-shaped radiating patch provided in this embodiment of the present invention after rotation by an angle;

[0032] Figure 7 The three-band artificial magnetic conductor provided in this embodiment of the utility model is based on... Figure 6 a. Frequency-reflection phase curve after rotation angle;

[0033] Figure 8 This is a schematic diagram of another artificial magnetic conductor unit provided in this embodiment of the present invention;

[0034] Figure 9 The three-band artificial magnetic conductor provided in this embodiment of the utility model is based on... Figure 8 Frequency-reflection phase curves after changing the opening structure of the first and second arc-shaped slots;

[0035] Figure 10 This is a frequency-reflection coefficient curve of the artificial magnetic conductor unit provided in this embodiment of the present invention;

[0036] Figure 11 This is a frequency-reflection phase curve of an artificial magnetic conductor unit provided in the embodiment;

[0037] Figure 12 This is a schematic diagram of a test antenna placed above an artificial magnetic conductor array;

[0038] Figure 13 for Figure 12 The diagram shows the overall reflection coefficient curve of the antenna after loading an artificial magnetic conductor array reflector.

[0039] Figure 14 It is the far-field radiation pattern of a three-band antenna loaded with an artificial magnetic conductor array;

[0040] Figure 15 This is a simulation result of the specific absorption rate of a three-band antenna under conditions close to a human body model;

[0041] Figure 16 This is a simulation result of the specific absorption rate of the three-band antenna with an artificial magnetic conductor array loaded according to an embodiment of the present invention under conditions close to a human body model;

[0042] Figure 17 This is an equivalent circuit diagram of the artificial magnetic conductor provided in this embodiment of the utility model;

[0043] Figure 18 This is a frequency-reflection phase curve of the artificial magnetic conductor provided in this embodiment of the present invention;

[0044] Figure 19 This is a schematic diagram of the structure of the artificial magnetic conductor unit provided in this embodiment of the utility model;

[0045] Figure 20 This is a schematic diagram of the dimensions of the artificial magnetic conductor unit provided in this embodiment of the present invention;

[0046] Figure 21 This is a schematic diagram showing the dimensions of the ground plane and / or substrate of the three-band artificial magnetic conductor provided in this embodiment of the present invention. Detailed Implementation

[0047] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0048] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0049] Figure 1 This is a schematic diagram of the structure of a three-band artificial magnetic conductor provided in an embodiment of the present invention; Figure 2 This is a top view of an artificial magnetic conductor array provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an artificial magnetic conductor unit provided in an embodiment of this utility model, for reference. Figure 1Figure 3 shows that the three-band artificial magnetic conductor provided in this embodiment includes: a substrate 1, an artificial magnetic conductor array 2 located on the first side surface of the substrate 1, and a ground plane 3 located on the second side surface of the substrate 1; the artificial magnetic conductor array 2 includes M×N periodically distributed artificial magnetic conductor units 21; the artificial magnetic conductor unit 21 includes: a quadrilateral radiating patch 211, four T-shaped grooves 212 located at the edges of the quadrilateral radiating patch 211, and a boomerang-shaped radiating patch 213 with etched arc grooves located in the middle of the quadrilateral radiating patch 211; the T-shaped groove 212 includes a first side T1 and a second side T2. 2. The first side T1 is parallel to the edge of the quadrilateral radiating patch 211, and the second side T2 is perpendicular to the edge of the quadrilateral radiating patch 211. The first side T1 of the four T-shaped slots 212 surrounds the boomerang-shaped radiating patch 213. The boomerang-shaped radiating patch 213 includes: a first part D1, a second part D2, a third part D3, and a fourth part D4. The first part D1 is a fan-shaped structure with three arc-shaped edges. The fan-shaped structure includes a first arc-shaped slot H1 and a second arc-shaped slot H2. Both the first arc-shaped slot H1 and the second arc-shaped slot H2 are slot structures with one open end. All the first arc-shaped slots H1 and the second arc-shaped slots H2 are... The center of groove H2 is the center of the boomerang-shaped radiating patch 213; the first part D1 rotates 90° counterclockwise around the center of the boomerang-shaped radiating patch 213 to coincide with the second part D2, the second part D2 rotates 90° counterclockwise around the center of the boomerang-shaped radiating patch 213 to coincide with the third part D3, and the third part D3 rotates 90° counterclockwise around the center of the boomerang-shaped radiating patch 213 to coincide with the fourth part D4; or the first part D1 rotates 90° clockwise around the center of the boomerang-shaped radiating patch 213 to coincide with the fourth part D4, and the fourth part D4 rotates 90° counterclockwise around the center of the boomerang-shaped radiating patch 213 to coincide with the fourth part D4. The center of 213 is rotated 90° clockwise to coincide with the third part D3, and the third part D3 is rotated 90° clockwise along the center of the boomerang-shaped radiating patch 213 to coincide with the second part D2; the first resonant frequency and the third resonant frequency are introduced by the T-shaped groove 212. The width of the first arc groove H1 and the second arc groove H2 or the radius of the boomerang-shaped radiating patch 213 are different, and the resonant position of the second resonant frequency is different; the first side surface and the second side surface are arranged opposite to each other; the frequency bands of the first resonant frequency, the second resonant frequency and the third resonant frequency increase sequentially; M and N are both positive integers greater than or equal to 2.

[0050] The tri-band artificial magnetic conductor provided in this embodiment of the utility model includes a substrate 1 and a first side surface of the substrate (i.e., Figure 1 The artificial magnetic conductor array 2 (shown on the upper surface of substrate 1) and the second side surface of substrate 1 (i.e., Figure 1 The ground plane 3 (on the lower surface of the substrate 1) shown in the figure comprises an artificial magnetic conductor array 2 consisting of M×N periodically distributed artificial magnetic conductor units 21, such as... Figure 2 As shown, in Figure 2 In the equation, M is 4 and N is 4. Figure 2 The example shown is a 4×4 artificial magnetic conductor unit 21. M and N can be positive integers greater than or equal to 2. See reference. Figure 3 The artificial magnetic conductor unit 21 includes a quadrilateral radiating patch 211 (i.e. a radiating patch with an overall quadrilateral structure). Each artificial magnetic conductor unit 21 includes four T-shaped grooves 212 located at the edges of the quadrilateral radiating patch 211, and a boomerang-shaped radiating patch 213 with etched arc grooves located in the middle of the quadrilateral radiating patch 211.

[0051] The T-slot 212 includes a first side T1 and a second side T2. The first side T1 is parallel to the edge of the quadrilateral radiating patch 211, and the second side T2 is perpendicular to the edge of the quadrilateral radiating patch 211. The first side T1 of the four T-slots 212 surrounds the boomerang-shaped radiating patch 213.

[0052] The boomerang-shaped radiating patch 213 includes a first part D1, a second part D2, a third part D3, and a fourth part D4. The first part D1 is a fan-shaped structure with three arc-shaped edges. The fan-shaped structure includes a first arc-shaped groove H1 and a second arc-shaped groove H2. Both the first arc-shaped groove H1 and the second arc-shaped groove H2 are groove structures with one open end, and the opening faces the edge of the fan-shaped structure near the center of the boomerang-shaped radiating patch 213. The center of all the first arc-shaped grooves H1 and the second arc-shaped grooves H2 is the center of the boomerang-shaped radiating patch 213. That is, the curvature of the first arc-shaped grooves H1 and the second arc-shaped grooves H2 is the same as the curvature of the fan-shaped structure.

[0053] The first part D1 is rotated counterclockwise by 90°, 180° and 270° along the center of the boomerang-shaped radial patch 213 to obtain the second part D2, the third part D3 and the fourth part D4 respectively;

[0054] Alternatively, the first part D1 can be rotated clockwise by 90°, 180°, and 270° respectively around the center of the boomerang-shaped radial patch 213 to obtain the fourth part D4, the third part D3, and the second part D2. It can be understood that the boomerang-shaped radial patch 213 has a centrally symmetrical structure.

[0055] Without etching, the zero-phase reflection frequency of the quadrilateral radiating patch 211 is 3.02 GHz. By etching T-shaped grooves 212 on each of its four sides, two resonant points at 2.43 GHz and 7.01 GHz are introduced into the T-shaped grooves 212, thereby achieving a dual-band in-phase reflection response.

[0056] After the quadrilateral radiating patch 211 and the T-slot 212 structure are introduced, the boomerang-shaped radiating patch 213 is introduced. The quadrilateral radiating patch 211 and the boomerang-shaped radiating patch 213 are coupled to achieve zero-phase reflection at 5.75 GHz, thereby realizing the three-band in-phase reflection function.

[0057] The quadrilateral radiating patch 211 introduces two main resonant modes through the T-shaped slot 212, corresponding to the first resonant frequency (low frequency band) and the third resonant frequency (high frequency band), namely 2.45 GHz and 7 GHz, respectively. The widths of the first arc-shaped slot H1 and the second arc-shaped slot (i.e., the gap width between the first arc-shaped slot H1 and the second arc-shaped slot H2) are different. By adjusting the gap width of the first arc-shaped slot H1 and the second arc-shaped slot H2, the resonant position of the second resonant frequency (mid frequency band) can be effectively adjusted, thereby realizing the function of three-band in-phase reflection.

[0058] The tri-band artificial magnetic conductor provided in this embodiment can effectively adjust the resonant positions of the first and third resonant frequencies by using a quadrilateral radiating patch and a T-shaped groove. By adding a boomerang-shaped radiating patch with an etched arc groove, the resonant position of the second resonant frequency can be effectively adjusted, achieving zero-phase reflection near the second resonant frequency. Through the triple resonance synergistic design, a tri-frequency in-phase reflection characteristic is formed, and it can effectively cover a wider range of resonant frequencies, meeting the application requirements of multi-frequency wearable communication systems.

[0059] Figure 4 This is a graph showing the reflection coefficient of a three-band artificial magnetic conductor as a function of frequency, provided in an embodiment of this utility model. Figure 5 This is a reflection phase curve diagram of a three-band artificial magnetic conductor provided in an embodiment of this utility model, for reference. Figure 4 The horizontal axis represents frequency in GHz, and the vertical axis represents reflection coefficient in dB. The frequencies from left to right are 2.43 GHz, 5.75 GHz, and 7.01 GHz, corresponding to reflection coefficients of -2.52 dB, -2.0 dB, and -1.49 dB, respectively. (Reference) Figure 5 The horizontal axis represents frequency in GHz. The frequencies from left to right are 2.43 GHz, 5.75 GHz, and 7.01 GHz, with a corresponding reflection phase of -180°.

[0060] Figure 6 This is a schematic diagram of the boomerang-shaped radiating patch provided in this embodiment of the present invention after rotation by an angle; Figure 7 The three-band artificial magnetic conductor provided in this embodiment of the utility model is based on... Figure 6 a. Frequency-reflection phase curve after rotation angle, as shown Figure 6 As shown, when the boomerang-shaped radiating patch rotates within the range of 0°-90° (compared to...), Figure 3 As shown, Figure 6 The pattern shown is the result of rotating a boomerang-shaped radial patch by 45°. The simulated structure is as follows: Figure 7 As shown in the simulation, the reflection phase curve remains basically unchanged, demonstrating that the three-band artificial magnetic conductor provided by this utility model has good structural robustness.

[0061] Figure 8 This is a schematic diagram of another artificial magnetic conductor unit provided in this embodiment of the present invention; Figure 9 The three-band artificial magnetic conductor provided in this embodiment of the utility model is based on... Figure 8 Frequency-reflection phase curves after changing the opening structure of the first and second arc-shaped slots are shown in the reference diagram. Figure 8-9 Plotting frequency on the x-axis and reflection phase on the y-axis, it is clear that the reflection phase curve of the boomerang-shaped radiating patch remains essentially unchanged after altering the opening direction and length of the first and second arc-shaped grooves (i.e., as shown in the image). Figure 9 In the study, after changing the opening direction and length of the first and second arc-shaped grooves, the curves of the three colors (which are curves of different colors at Phi=0°, Phi=30° and Phi=60° respectively) almost overlapped. Moreover, after electromagnetic waves with different polarization angles were perpendicularly incident on another structure, the reflectivity remained almost unchanged, indicating that it has good polarization insensitivity characteristics.

[0062] Figure 10 This is a frequency-reflection coefficient curve of the artificial magnetic conductor unit provided in this embodiment of the invention. Figure 11 This is a frequency-reflection phase curve of an artificial magnetic conductor unit provided in the embodiment, for reference. Figure 10-11 , Figure 10 The frequency of the artificial magnetic conductor unit is plotted on the x-axis, and the reflection coefficient of the artificial magnetic conductor unit is plotted on the y-axis. Figure 11 The graph uses the frequency of the artificial magnetic conductor unit as the abscissa and the reflection phase of the artificial magnetic conductor unit as the ordinate, illustrating the changes in reflectivity and reflection phase when electromagnetic waves with different polarization angles are perpendicularly incident on the artificial magnetic conductor unit. It can be seen that the reflectivity of the artificial magnetic conductor unit exhibits only a slight difference, indicating its excellent polarization insensitivity. This characteristic enables the design to maintain stable electromagnetic performance in complex application scenarios such as dynamic wearable devices and posture changes, demonstrating excellent environmental adaptability and robustness.

[0063] Figure 12 This is a schematic diagram of a test antenna placed above an artificial magnetic conductor array; Reference Figure 12 Antenna X is placed above the artificial magnetic conductor array. This embodiment of the invention does not limit the structure of the antenna.

[0064] Figure 13 for Figure 12 The overall reflection coefficient curve of the antenna after loading an artificial magnetic conductor array reflector is shown in the figure. (Refer to...) Figure 12 After loading the artificial magnetic conductor array, the resonant points of antenna X in the three working frequency bands of 2.45GHz, 5.8GHz and 7GHz remained basically stable. The overall trend of the reflection coefficient curve was highly consistent with the simulation results, with only a slight frequency shift near 7GHz. This verifies that the artificial magnetic conductor array structure has good antenna compatibility, frequency stability and practical application feasibility in multiple frequency bands.

[0065] Figure 14 This is the far-field radiation pattern of a three-band antenna with an artificial magnetic conductor array, for reference. Figure 14 Figures (a) and (b) show the normalized two-dimensional and three-dimensional far-field radiation patterns of the antenna at 2.45 GHz, respectively; Figures (c) and (d) show the normalized two-dimensional and three-dimensional far-field radiation patterns at 5.8 GHz; and Figures (e) and (f) show the normalized two-dimensional and three-dimensional far-field radiation patterns at 7 GHz. Simulation results show that at the three operating frequencies of 2.45 GHz, 5.8 GHz, and 7 GHz, the forward radiation gain of the antenna is significantly higher than the backward radiation gain, with the gain difference exceeding 10 dBi. This result verifies that the artificial magnetic conductor array reflector possesses good back-radiation suppression capability across multiple frequency bands, significantly improving the antenna's forward radiation performance and directivity.

[0066] Figure 15 This is a simulation result of the specific absorption rate of a three-band antenna under conditions close to a human body model. (Reference) Figure 15 (a), (b), and (c) correspond to the three operating frequency bands of 2.45 GHz, 5.8 GHz, and 7 GHz, respectively. Simulation results show that the SAR values ​​at each operating frequency are 1.46 W / kg, 1.01 W / kg, and 1.23 W / kg, respectively. The simulation results indicate that, under conditions of close proximity to the human body, the antenna produces significant back radiation in all frequency bands, causing a certain degree of electromagnetic energy absorption by human tissue. This result will serve as a comparative reference for evaluating the SAR improvement effect after subsequently adding an artificial magnetic conductor structure.

[0067] Figure 16 This is a simulation result of the specific absorption rate of the three-band antenna with an artificial magnetic conductor array loaded according to an embodiment of this utility model under conditions close to a human body model. (Reference) Figure 16 At the operating frequency of 2.45 GHz, the SAR value of 10g tissue is 0.159 W / kg; at 5.8 GHz it is 0.0785 W / kg; and at 7 GHz it is 0.0498 W / kg.

[0068] According to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and IEEE C95.1-2019 standards, the SAR limit for 10g tissue units is 2W / kg. Therefore, the artificial magnetic conductor array described above can effectively suppress electromagnetic radiation from the antenna to the human body, significantly reduce the SAR value, and ensure the electromagnetic safety of wearable devices in multi-frequency near-human environments, demonstrating promising practical application prospects.

[0069] Figure 17 This is an equivalent circuit diagram of the artificial magnetic conductor provided in this embodiment of the invention. Figure 18 This is a frequency-reflection phase curve of the artificial magnetic conductor provided in this embodiment of the invention, for reference. Figure 17-18 The equivalent circuit model consists of a series incident impedance and four LC resonant branches. Each LC branch corresponds to a different resonant mode in the structure, used to simulate the in-phase reflection characteristics of the artificial magnetic conductor in the 2.45GHz, 5.8GHz, and 7GHz frequency bands. Based on the structural functional division and circuit fitting results, the dominant relationship of each branch in the frequency domain is as follows:

[0070] The first set of parallel LC resonant branches (L1 and C1) mainly simulates the vertical coupling capacitance formed between the quadrilateral radiating patch and the ground plane below, as well as the patch's own inductive reactance. This branch controls the zero-phase reflection characteristics of the artificial magnetic conductor unit at low frequencies (approximately 2.45 GHz).

[0071] The second set of series LC resonant branches (L2 and C2) is used to simulate the current path and inductive-capacitive behavior caused by the boomerang-shaped radiating patch, mainly controlling the reflection phase transition in the mid-frequency band (about 5.8 GHz).

[0072] The third and fourth sets of series LC branches (L3 / C3 and L4 / C4) are configured in parallel and work together to form a composite resonant mode in the high-frequency band (approximately 7 GHz). The resonant response in this band originates from multiple edge slots, slits, and local current coupling effects in the structure.

[0073] In summary, each branch of the equivalent circuit undertakes the low-frequency, mid-frequency, and high-frequency resonance tasks in the three-frequency band reflection characteristic control, and the circuit simulation results are consistent with the three-dimensional structural model, which can effectively realize the rapid design and optimization of artificial magnetic conductor units.

[0074] Table 1 shows the component values ​​of the equivalent circuit diagram of the artificial magnetic conductor unit.

[0075] inductance Value (nH) capacitance Value (pF) ​ 1.00 C1 0.01 <![CDATA[L2]]> 19.57 C2 0.04 <![CDATA[L3]]> 11.93 C3 0.32 L4 8.59 C4 0.05

[0076] Table 1

[0077] Table 2 shows the measured gain comparison results of the antenna without the loading of artificial magnetic conductor units within the permitted frequency band.

[0078]

[0079] Table 2

[0080] The three operating frequency bands involved—2.45GHz, 5.8GHz, and 7GHz—are located in the globally widely open ISM bands (2.400–2.4835GHz and 5.725–5.875GHz) and the 6.425–7.125GHz range, currently considered as an extended band for Wi-Fi 6E and a candidate band for future 6G communication, respectively, demonstrating good spectrum compatibility and practical application prospects. This table verifies the effectiveness of the described artificial magnetic conductor structure in improving antenna radiation performance.

[0081] Table 3 shows the comparison results of the specific absorption rate (SAR) of the antenna when it is attached to a human body model.

[0082]

[0083] Table 3

[0084] In the three operating frequency bands of 2.45 GHz, 5.8 GHz and 7 GHz, the SAR value was significantly reduced after loading the artificial magnetic conductor array, indicating that the structure can effectively suppress the back radiation of the antenna, reduce the deposition of electromagnetic energy in human tissue, and thus improve the electromagnetic safety of the system.

[0085] Figure 19 This is a schematic diagram of the structure of the artificial magnetic conductor unit provided in an embodiment of this utility model, for reference. Figure 19 Optionally, the three-band artificial magnetic conductor unit 21 provided in this embodiment of the present invention further includes: a circular groove 214;

[0086] The circular groove 214 is located within the area enclosed by the first side T1 of the four T-shaped grooves 212, and the boomerang-shaped radiating patch 213 is disposed within the circular groove 214; the center of the circular groove 214 coincides with the center point of the boomerang-shaped radiating patch 213.

[0087] Specifically, a circular groove 214 is provided in the middle of the quadrilateral radiating patch 211, and a boomerang-shaped radiating patch 213 is placed in the circular groove 214. The circular groove 214 is located in the area enclosed by the first side T1 of the four T-shaped grooves 212, and the center of the circular groove 214 coincides with the center point of the boomerang-shaped radiating patch 213.

[0088] Figure 20 This is a schematic diagram of the dimensions of the artificial magnetic conductor unit provided in this embodiment of the present invention; Figure 21This is a schematic diagram showing the dimensions of the ground plane and / or substrate of the three-band artificial magnetic conductor provided in this embodiment of the present invention. Optionally, the outer diameter R1 of the circular groove is 8.3mm-8.5mm, and preferably, the outer diameter R1 of the circular groove is 8.4mm.

[0089] Optionally, the groove length C1 of the first side is 14mm-15mm, and the groove width K1 of the first side is 0.8mm-1.0mm. Preferably, the groove width K1 of the first side is 0.8mm, and the groove length C1 of the first side is 14.7mm.

[0090] Specifically, when the length C1 of the first side groove increases from 14mm to 15mm, the third resonant frequency increases from 6.82GHz to 7.09GHz, while the first and second resonant frequencies remain stable.

[0091] When the width K1 of the first side increases from 0.8mm to 1.0mm, the first resonant frequency decreases from 2.46GHz to 2.29GHz, the third resonant frequency decreases from 7.04GHz to 6.83GHz, and the second resonant frequency remains basically unchanged.

[0092] Optionally, the groove length C2 on the second side is 2.2mm-2.6mm, and the groove width K2 on the second side is 0.8mm-1.2mm. Preferably, the groove length C2 on the second side is 2.4mm, and the groove width K2 on the second side is 1.00mm.

[0093] Specifically, when the length C2 of the second side increases from 2.2mm to 2.6mm, the first resonant frequency decreases from 2.53GHz to 2.39GHz, the third resonant frequency decreases from 7.12GHz to 6.96GHz, and the second resonant frequency remains stable.

[0094] Optionally, the radius r1 of the boomerang-shaped radiating patch is 7.8mm-8.0mm.

[0095] Specifically, when the radius r1 of the boomerang-shaped radiating patch increases from 7.8 mm to 8.0 mm, the second resonant frequency decreases from 6.06 GHz to 5.68 GHz, while the other two resonant frequencies remain basically unchanged.

[0096] Optionally, the width g of the first arc groove and the second arc groove is 0.3mm-0.9mm.

[0097] Specifically, when the width g of the first and second arc-shaped grooves increases from 0.3 mm to 0.9 mm, the first and third resonant frequencies remain basically unchanged, while the second resonant frequency decreases from 5.96 GHz to 5.71 GHz.

[0098] The above results show that by reasonably adjusting the size of the boomerang-shaped patch and the parameters of the first and second arc-shaped slots, the zero-phase reflection position of the three-band system can be flexibly controlled, thereby achieving fine tuning of the working performance of the artificial magnetic conductor and meeting the design requirements of the multi-frequency wearable antenna system.

[0099] Continue to refer to Figure 1 and Figure 21 The edge length L2 of the ground plane 3 is the same as the edge length L2 of the substrate 1, and the edge length of the substrate 1 is greater than the edge length L1 of the artificial magnetic conductor array 2.

[0100] like Figure 21 As shown, the edge length L2 of the ground plane 3 is the same as the edge length L2 of the base 1. That is, from the top view, the two structures (i.e., the ground plane 3 and the base 1) overlap. The edge length L2 of the base 1 or the edge length L2 of the ground plane 3 is greater than the edge length L1 of the artificial magnetic conductor array 2. Preferably, L2 is 25 mm and L1 is 24.5 mm.

[0101] Optional, see reference Figure 1 In the three-band artificial magnetic conductor provided in this embodiment, the ground plane 3 and the artificial magnetic conductor array 2 are both made of conductive cloth; the substrate 1 is made of felt.

[0102] By setting the materials of the ground plane 3 and the artificial magnetic conductor array 2 as conductive cloth, the current transmission can be better and the electrical signal can be enhanced. The material of the substrate 1 is felt with a dielectric constant of about 1.2 and a thickness of 1.5 mm. The thickness of the attached conductive cloth is 0.08 mm.

[0103] The material selection is mainly used to verify the feasibility and flexibility of the artificial magnetic conductor array structure, and does not limit the type of substrate. In practical applications, other dielectric materials with suitable dielectric properties, flexibility or mechanical strength can be selected according to the requirements.

[0104] This utility model embodiment also provides a wearable device, including the three-band artificial magnetic conductor in any of the above utility model embodiments.

[0105] The wearable device provided in this embodiment of the present invention can achieve the same technical effect as the three-band artificial magnetic conductor provided in the above-mentioned embodiment of the present invention, and will not be described again here.

[0106] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A three-band artificial magnetic conductor, characterized in that, include: A substrate, an array of artificial magnetic conductors located on a first side surface of the substrate, and a ground plane located on a second side surface of the substrate; The artificial magnetic conductor array comprises M×N periodically distributed artificial magnetic conductor units; The artificial magnetic conductor unit includes: a quadrilateral radiating patch, four T-shaped grooves located at the edges of the quadrilateral radiating patch, and a boomerang-shaped radiating patch with etched arc grooves located in the middle of the quadrilateral radiating patch. The T-slot includes a first side and a second side. The first side is parallel to the edge of the quadrilateral radiating patch, and the second side is perpendicular to the edge of the quadrilateral radiating patch. The first sides of the four T-slots surround the boomerang-shaped radiating patch. The boomerang-shaped radiation patch includes: a first part, a second part, a third part, and a fourth part; The first part is a fan-shaped structure with three arc-shaped edges. The fan-shaped structure includes a first arc-shaped groove and a second arc-shaped groove. Both the first arc-shaped groove and the second arc-shaped groove are groove structures with one end open. The center of all the first arc-shaped grooves and the second arc-shaped grooves is the center of the boomerang-shaped radial patch. The first portion is rotated 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the second portion; the second portion is rotated 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the third portion; and the third portion is rotated 90° counterclockwise around the center of the boomerang-shaped radiating patch to coincide with the fourth portion; or the first portion is rotated 90° clockwise around the center of the boomerang-shaped radiating patch to coincide with the fourth portion; and the fourth portion is rotated 90° clockwise around the center of the boomerang-shaped radiating patch to coincide with the third portion. The three parts overlap, with the third part rotating 90° clockwise around the center of the boomerang-shaped radiating patch to overlap with the second part; the first and third resonant frequencies are introduced by the T-shaped groove, and the widths of the first and second arc-shaped grooves or the radius of the boomerang-shaped radiating patch are different, resulting in different resonant positions of the second resonant frequency; wherein the first and second side surfaces are arranged opposite to each other; the frequency bands of the first, second, and third resonant frequencies increase sequentially; M and N are both positive integers greater than or equal to 2.

2. The three-band artificial magnetic conductor according to claim 1, characterized in that, The artificial magnetic conductor unit further includes: a circular groove; The circular groove is located within the area enclosed by the first sides of the four T-shaped grooves, and the boomerang-shaped radiating patch is disposed within the circular groove; the center of the circular groove coincides with the center point of the boomerang-shaped radiating patch.

3. The three-band artificial magnetic conductor according to claim 2, characterized in that, The outer diameter of the circular groove is 8.3mm-8.5mm.

4. The three-band artificial magnetic conductor according to claim 1, characterized in that, The length of the groove on the first side is 14mm-15mm, and the width of the groove on the first side is 0.8mm-1.0mm.

5. The three-band artificial magnetic conductor according to claim 1, characterized in that, The length of the groove on the second side is 2.2mm-2.6mm, and the width of the groove on the second side is 0.8mm-1.2mm.

6. The three-band artificial magnetic conductor according to claim 1, characterized in that, The radius of the boomerang-shaped radiating patch is 7.8 mm to 8.0 mm.

7. The three-band artificial magnetic conductor according to claim 6, characterized in that, The widths of the first arc-shaped groove and the second arc-shaped groove are 0.3mm-0.9mm.

8. The three-band artificial magnetic conductor according to claim 1, characterized in that, The edge length of the ground plane is the same as the edge length of the substrate, and the edge length of the substrate is greater than the edge length of the artificial magnetic conductor array.

9. The three-band artificial magnetic conductor according to claim 1, characterized in that, The materials of the ground plane and the artificial magnetic conductor array both include conductive cloth; the material of the substrate is felt.

10. A wearable device, characterized in that, Includes the three-band artificial magnetic conductor as described in any one of claims 1-9.

Images