Directional diagram fixed frequency switchable miniature fabric wearable antenna

Abstract

The invention relates to a directional diagram fixed-frequency switchable miniature fabric wearable antenna, which belongs to the technical field of wearable wireless communication, and comprises a patch layer, a substrate layer and a bottom surface layer which are positioned on the upper and lower end surfaces of the patch layer, a feed probe and symmetrically arranged snap fastener devices, the two metal via hole pipes penetrate through the substrate layer and are connected with the two communication clamping pieces respectively, and the two communication clamping pieces enable the switching diode to be switched on and off by controlling direct current bias voltage, so that switching of the antenna between a patch mode and a monopole mode is achieved. Reconstruction of a working mode and a radiation pattern is realized through a method of setting direct current bias voltage of the snap switch device, miniaturization of the antenna is realized through a method of using a semi-structure, the plane size is only 0.09 lambda2, and the antenna is respectively in a patch mode and a monopole mode under the condition that the direct current bias voltage is 0V and 5V at the frequency of 2.45 GHz, so that the antenna can be applied to the field of antenna communication. Radiation directional diagrams are suitable for in-vitro communication and body surface communication respectively.

Description

Technical Field

[0001] The present invention relates to the technical field of wearable wireless communications, and in particular to a miniaturized wearable fabric antenna with a fixed-frequency switchable directional pattern. Background Art

[0002] In wireless body area networks, external and on-body communications require different radiation directions from wearable antennas. Wearable antennas with fixed-frequency, switchable directivity patterns can adjust their beam direction based on specific needs, ensuring multi-directional signal coverage while avoiding ineffective radiation in non-transmission directions. This facilitates spatial reuse of single-chip antennas in wearable applications.

[0003] In the existing technology, the pattern diversity technology sets multiple groups of stacked / juxtaposed radiators or metasurface structures with multiple characteristic modes in the wearable antenna structure, and sets corresponding multiple ports in the feeding network. By switching the feeding ports, different radiation patterns are switched at a fixed frequency. The pattern diversity technology can effectively realize the pattern switching at a fixed frequency, but the multiple radiators or metasurface structures will cause the cross-sectional thickness or planar size of the wearable antenna to increase. At the same time, the multi-port design also makes the feeding network structure more complicated.

[0004] In addition, mode reconstruction technology reconfigures the antenna's operating mode by setting a switching circuit in the wearable antenna's radiator and feed structure, and controlling the on-off state of the switching circuit through a bias circuit or mechanical switch, thereby switching the radiation pattern at a fixed frequency. Compared with pattern diversity technology, mode reconstruction technology usually does not require the design of a multi-port feed network, but the planar size of the patch antenna designed based on this technology is no less than 0.22λ. 2 (λ is the wavelength of the electromagnetic wave in the substrate medium), which limits the application of this technology in fabric wearable antennas and makes it difficult to meet the miniaturization requirements of fabric wearable devices. Summary of the Invention

[0005] The present invention aims to solve the above technical problems and provide a miniaturized wearable fabric antenna with a fixed-frequency switchable directional pattern.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0007] A miniaturized wearable textile antenna with a fixed-frequency switchable directional pattern comprises a patch layer, a substrate layer and a bottom layer located at the upper and lower ends of the patch layer, a feeding probe, and a symmetrically arranged snap-on device.

[0008] The snap-on device includes a connecting card arranged on the bottom layer and the patch layer, a PCB layer in the substrate layer, and a base sheet layer arranged at the upper and lower ends of the PCB layer;

[0009] The PCB layer includes a copper-clad wire and a switching diode, a resistor, and an inductor connected in series through the copper-clad wire. Metal vias are installed at the upper and lower ends of the copper-clad wire. The two metal vias penetrate the substrate layer and are respectively connected to two connecting clips. The two connecting clips control the DC bias voltage to turn the switching diode on and off, thereby realizing the switching of the antenna between the patch mode and the monopole mode.

[0010] Preferably, the patch layer is located at the center of the top surface of the substrate layer, and its length is twice its width; the bottom layer is located at the bottom surface of the substrate layer, and its size is the same as that of the bottom surface of the substrate layer and is symmetrical with respect to the center.

[0011] Preferably, the feeding probe is located on the right side of the horizontal center line of the antenna, 4.8 mm horizontally away from the center point, and is a copper cylinder with the top end connected to the patch layer and the bottom end insulated from the bottom surface layer.

[0012] Preferably, the snap-fit ​​device is located on the horizontal center line of the antenna, symmetrically placed left and right, and the distance between the snap-fit ​​device and the center point is 12 mm.

[0013] Preferably, the patch layer and the bottom layer are both made of conductive cloth material with a square resistance of 0.04Ω; the substrate layer is a foam material sheet with a thickness of 3.2mm, a relative dielectric constant of 1.06, and a loss tangent of 0.0001.

[0014] Preferably, the two connecting clips are arranged in a mirror image, and the connecting clips include a connecting male buckle, a female buckle and a spring. The male buckle includes a male buckle ball head, a male buckle rod and a male buckle base. The male buckle ball head is connected to the male buckle base through the male buckle rod, and the male buckle base is in contact with the substrate layer. The spring is a bent metal round bar, and the outer end point is connected to the inner side of the outer edge of the female buckle by welding. The upper end of the spring is connected to the male buckle ball head, and the female buckles of the two connecting clips are in contact with the patch layer and the bottom layer respectively.

[0015] Preferably, the PCB layer is located at the center of the substrate layer, the two metal via tubes are of the same height, and the metal via tubes pass through the substrate layer to connect to the male buckle base.

[0016] Preferably, the substrate layer, PCB layer and male buckle base are of equal length.

[0017] Preferably, when the DC bias voltage is 0V, the switching diode is disconnected, the snap-fit ​​device is not connected to the patch layer and the bottom layer, the antenna operates in patch mode, and the radiation pattern has a single main lobe in the normal direction of the xy plane;

[0018] When the DC bias voltage is 5V, the switching diode is turned on, and the snap-on device acts as a short-circuit pin connecting the patch layer and the bottom layer. The antenna operates in monopole mode, and the dual main lobes of the radiation pattern are between the xy plane and its normal direction.

[0019] After adopting the above structure, the present invention has the following advantages:

[0020] The present invention realizes the reconstruction of the working mode and radiation pattern by setting the DC bias voltage of the snap switch device, and realizes the miniaturization of the antenna by using a semi-structured method, and the plane size is only 0.09λ 2 .

[0021] Moreover, at a frequency of 2.45 GHz, the antenna is in patch and monopole modes when the DC bias voltage is 0 V and 5 V, respectively, and its radiation pattern is suitable for in vitro communication and surface communication, respectively.

[0022] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 is a top view of the present invention;

[0025] Figure 2 It is a bottom view of the present invention;

[0026] Figure 3 is a side view of the present invention;

[0027] Figure 4 It is a structural schematic diagram of the snap button device of the present invention;

[0028] Figure 5 It is a schematic diagram of the size numbers of the snap fastener device of the present invention;

[0029] Figure 6 It is a schematic diagram of the installation of the spring of the present invention;

[0030] Figure 7 It is a structural schematic diagram of the PCB layer of the present invention;

[0031] Figure 8 It is a simulation schematic diagram of the present invention;

[0032] Figure 9Schematic diagram of the disconnected state of the snap-on device of the antenna of the present invention in simulation / actual measurement in free space;

[0033] Figure 10 Schematic diagram of the conductor state of the snap-fit ​​device of the antenna of the present invention in simulation / measurement in free space;

[0034] Figure 11 This is a schematic diagram of the structure of the antenna of the present invention placed in a human tissue model;

[0035] Figure 12 This is a SAR simulation diagram of the present invention when the bias voltage is 0V;

[0036] Figure 13 This is a SAR simulation diagram of the present invention when the bias voltage is 5V;

[0037] Figure 14 This is a graph showing the return loss actually measured in the bending state of the present invention.

[0038] As shown in the figure: 1. Snap-on device; 11. Male snap ball head; 12. Female snap; 13. Male snap rod; 14. Male snap base; 15. Metal via; 16. Substrate layer; 17. PCB layer; 171. Switching diode; 172. Resistor; 173. Inductor; 174. Copper-clad wire; 18. Spring; 2. SMD layer; 3. Substrate layer; 4. Bottom layer; 5. Feed probe. DETAILED DESCRIPTION

[0039] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0040] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0041] The present invention will be described in further detail below in conjunction with the full text.

[0042] Combined with attachment Figures 1-14A miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern comprises a patch layer 2, a substrate layer 3 and a bottom layer 4 located at the upper and lower ends of the patch layer 2, a feeding probe 5, and a symmetrically arranged snap-on device 1;

[0043] The snap-on device 1 includes connecting clips provided on the bottom layer 4 and the patch layer 2, a PCB layer 17 within the substrate layer 3, and substrate layers 16 provided at the upper and lower ends of the PCB layer 17.

[0044] The PCB layer 17 includes a copper-clad wire 174 and a switching diode 171, a resistor 172 and an inductor 173 connected in series through the copper-clad wire 174. Metal vias 15 are installed at the upper and lower ends of the copper-clad wire 174. The two metal vias 15 pass through the substrate layer 16 and are respectively connected to two connecting clips. The two connecting clips control the DC bias voltage to turn on and off the switching diode 171, thereby realizing the switching of the antenna between patch mode and monopole mode.

[0045] When the present invention is implemented, the two female buckles 12 of a single connecting card are divided into an upper female buckle and a lower female buckle. A DC bias voltage is set between the upper female buckle and the lower female buckle, and the positive and negative poles of the DC bias voltage are connected to the upper female buckle and the lower female buckle. When the power is 0V, the switching diode 171 is disconnected. When the power is 5V, the switching diode 171 is turned on. Through the four-button switch device 1, the patch layer 2 and the bottom layer 4 are short-circuited.

[0046] The patch layer 2 is located at the center of the top surface of the substrate layer 3, and its length is twice its width; the size of the patch layer 2 is half of the traditional microstrip antenna, forming a semi-structured antenna; the bottom layer 4 is located on the bottom surface of the substrate layer 3, and its size is the same as that of the bottom surface of the substrate layer 3 and is symmetrical with the center.

[0047] The feeding probe 5 is located on the right side of the horizontal center line of the antenna, 4.8 mm horizontally away from the center point, and is a copper cylinder with its top end connected to the patch layer 2 and its bottom end insulated from the bottom surface layer 4.

[0048] In the specific implementation of the present invention, the patch layer 2 and the bottom layer 4 are both composed of a conductive cloth material of model NCS95R-CR with a square resistance of 0.04Ω; the substrate layer is a PF-4 foam material sheet with a thickness of 3.2mm, a relative dielectric constant of 1.06, and a loss tangent of 0.0001.

[0049] When the present invention is specifically implemented, Figure 1-Figure 4As shown, the snap-on device 1 is located on the horizontal center line of the antenna, symmetrically placed on the left and right, and the snap-on device is 12 mm away from the center point. The two connecting clips are mirror-set, and the connecting clips include a male buckle, a female buckle 12 and a spring 18. The male buckle includes a male buckle ball head 11, a male buckle rod 13 and a male buckle base 14. The male buckle ball head 11 is connected to the male buckle base 14 through the male buckle rod 13, and the male buckle base 14 is in contact with the substrate layer 16. The spring 18 is a bent metal round bar, and the outer end point is connected to the inner side of the outer edge of the female buckle 12 by welding. The upper end of the spring 18 is connected to the male buckle ball head 11. The female buckles 12 of the two connecting clips are in contact with the patch layer 2 and the bottom layer 4 respectively. The patch layer 2 connected to the bottom surface of the base of the upper female buckle 12 is disconnected due to the passage of the upper male buckle, and the bottom layer 4 connected to the bottom surface of the base of the lower female buckle 12 is disconnected due to the insertion of the lower male buckle. The disconnection spacing of the patch layer 2 is equal to the disconnection spacing of the bottom layer 4.

[0050] The PCB layer 17 is located at the center of the substrate layer 16 , and the two metal vias 15 are at the same height. The metal vias 15 pass through the substrate layer 16 and connect to the male buckle base 14 .

[0051] When the present invention is specifically implemented, Figure 5 As shown, the lengths of the substrate layer 16, the PCB layer 17, and the male buckle base 14 are equal, specifically, 7 mm.

[0052] When the DC bias voltage is 0V, the switching diode 171 is disconnected, the snap-on device 1 is not connected to the patch layer 2 and the bottom layer 4, the antenna operates in patch mode, and the radiation pattern has a single main lobe in the normal direction of the xy plane, which is suitable for in vitro communication in wearable applications;

[0053] When the DC bias voltage is 5V, the switching diode 171 is turned on, and the snap-on device 1 acts as a short-circuit pin connecting the patch layer 2 and the bottom layer 4. The antenna operates in a monopole mode, and the dual main lobes of the radiation pattern are located between the xy plane and its normal direction, which is suitable for surface communication.

[0054] Based on the structure of a rectangular patch antenna, the working mode and radiation pattern are reconstructed by setting the DC bias voltage of a four-click switch device. At a frequency of 2.45 GHz, the antenna is in patch and monopole mode when the four-click switch device is in the disconnected and on states, respectively. Its radiation pattern is suitable for in-vitro and on-body communication, respectively.

[0055] By using a semi-structural approach to miniaturize the antenna, the planar size of the patch layer of the designed antenna is reduced to half of the previous size, only 0.09λ, without sacrificing antenna performance and functionality. 2 .

[0056] When the present invention is specifically implemented, Figure 5As shown, the value ranges of the antenna parameters are: Lg value range 95-105mm, Wg value range 73-89mm, Lp value range 48-64mm, Wp value range 22-32mm, Xb value range 11-13mm, Xf value range 4.5-5mm, H value range 1.6-4.8mm, L1=2mm, L2=3mm, L3=8mm, L4=1.5mm, L5=0.3mm, L6=0.5mm, L7=1.6mm, L8=4mm, L9=7mm.

[0057] During processing, NCS95R-CR conductive cloth is used to make the patch layer and the bottom layer, PF-4 foam material is used as the substrate, and the switching diode in the snap-on device is a high-frequency model to ensure stable switching at 2.45GHz.

[0058] The antenna of the present invention is simulated and analyzed:

[0059] The simulation results are as follows Figure 8 The solid line represents the simulation data, and the dotted line represents the measured data. The resonant frequency of the antenna when the snap-on device is disconnected and connected is 2.45 GHz, and the relative -10 dB impedance bandwidth is 1.7% and 5.1%, respectively.

[0060] The antenna's main polarization gain pattern in free space at 2.45 GHz. The specific antenna's simulated (2.45 GHz) and measured (2.47 GHz) main polarization gain patterns in free space are as follows: Figure 9 and Figure 10 shown.

[0061] Simulation results show that when the snap-on mechanism is disconnected, the antenna's radiation pattern features a single main lobe in the normal direction of the xy plane, with a maximum main polarization gain of 8.3 dBi, making it suitable for external communication in wearable applications. When the snap-on mechanism is on, the radiation pattern features dual main lobes located between the xy plane and its normal direction, with a maximum main polarization gain of 3.8 dBi, making it suitable for on-body communication. In both states, the radiation efficiency exceeds 95%, meeting the high radiation efficiency performance requirements of wearable antenna design principles. When the snap-on mechanism is disconnected, the antenna operates in patch mode, where the majority of far-field radiation is driven by the current flowing through the patch. The ground plane effectively reduces the antenna's back-radiation intensity. When the snap-on mechanism is on, the antenna operates in monopole mode, where the current flowing through the patch flows into the ground plane through the metal snap-on mechanism. Current flowing on the bottom surface also contributes to far-field radiation, resulting in significantly higher back-radiation intensity compared to the patch mode.

[0062] The antenna of the present invention is placed on the surface of the human body, and the change of the antenna performance is constructed as follows. Figure 11The stacked human tissue model shown is placed 5 mm below the antenna for simulation.

[0063] The model consists of three layers of tissue: skin, fat, and muscle. The thickness, density, relative dielectric constant, and conductivity of each layer are shown in Table 1.

[0064] The simulated return loss curve and main polarization gain pattern of the antenna placed on the human tissue model are shown as follows: Figure 8 、 Figure 9 、 Figure 10 As shown in .

[0065] Simulation results show that when the snap-on mechanism is disconnected, the simulated return loss curve on the human body surface almost completely overlaps with the simulated curve in free space, with a significant decrease in back-radiation intensity and a slight reduction in radiation efficiency to 87%. When the snap-on mechanism is turned on, the resonant frequency rises slightly to 2.47 GHz, and the back-radiation intensity also decreases significantly, with a significant reduction in radiation efficiency to 72%. Human tissue is a lossy dielectric. When electromagnetic waves enter it, they reflect and absorb a portion of the radiated energy, resulting in a decrease in the antenna's back-radiation intensity and radiation efficiency. Simulation results show that when the antenna is in monopole mode, the resonant frequency shift and radiation efficiency drop caused by the human body are more pronounced, further verifying the radiation mechanism in the two operating modes mentioned above.

[0066] Table 1 Thickness, density, relative dielectric constant and conductivity of each layer of human tissue

[0067]

[0068] When the present invention is specifically implemented, Figure 12 and Figure 13 The figure shows the simulated 1g average SAR distribution of the antenna in a human tissue model at a frequency of 2.45 GHz and input powers of 0 and 5 W, respectively. In patch and monopole modes, the maximum SAR values ​​in the human tissue model are 0.15 and 0.35 W / kg, respectively, both well below the safety limits specified in IEEE C95.1-2005 (1g average SAR no higher than 1.6 W / kg) and EN50361-2001 (10g average SAR no higher than 2.0 W / kg), indicating that there is no potential electromagnetic hazard when the antenna is placed on the human body surface.

[0069] The return loss parameters of the antenna sample in the unbent state were measured in free space and on the human body surface. The measured return loss curve is shown in Figure 2. Figure 14As shown in the figure, the measured data for the antenna in free space shows that when the snap-on mechanism is disconnected, the resonant frequency is 2.47 GHz, with a relative -10 dB impedance bandwidth of 2.2%. When the snap-on mechanism is connected, the resonant frequency is also 2.47 GHz, with a relative bandwidth of 7.7%. The measured and simulated curves are generally consistent, with a slight shift in the resonant frequency likely due to sample processing errors. The measured return loss curve for the antenna on the human body surface also conforms to the simulation expectations. In patch mode with the snap-on mechanism disconnected, the curve is essentially identical to the measured free space curve, while in monopole mode with the snap-on mechanism connected, a slight resonant frequency shift occurs.

[0070] The antenna of the present invention solves the problems of large size and complex structure of existing wearable antennas with directional pattern switching, realizes directional pattern reconstruction at a fixed frequency (2.45GHz), and meets the miniaturization requirements of fabric wearable devices.

[0071] Miniaturized design: using semi-structured patch layer, the plane size is only 0.09λ 2 , which is much smaller than the 0.22λ of existing pattern reconstruction technology. 2 , suitable for fabric wearable scenarios.

[0072] Fixed-frequency switching: Through the on-off control of the four-button device, precise switching of two radiation patterns is achieved at 2.45GHz, respectively adapting to in-vitro and on-body communications.

[0073] High radiation efficiency: The radiation efficiency in both modes exceeds 95% (free space), and still maintains 87% (patch mode) and 72% (monopole mode) in the human tissue environment, meeting the performance requirements of wearable devices.

[0074] High safety: 1g average SAR values ​​are 0.15W / kg (patch mode) and 0.35W / kg (monopole mode), far below the IEEE and EN standard limits.

[0075] Patch mode (0V bias): The snap-on mechanism is disconnected, and the antenna is mainly excited by the patch layer current. The radiation pattern presents a single main lobe in the normal direction of the xy plane, with a maximum gain of 8.3dBi, suitable for in vitro long-distance communication.

[0076] Monopole mode (5V bias): The snap-on device is turned on, and the patch current flows into the bottom layer through the metal snap-on device. The bottom current participates in radiation, forming a double main lobe in the xy plane and the normal direction, with a maximum gain of 3.8dBi, which is suitable for short-range communication on the body surface.

[0077] The present invention and its embodiments are described above. This description is not restrictive. What is shown in the full text is only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs a structure and embodiment similar to this technical solution without creatively designing, they shall all fall within the scope of protection of the present invention.

Claims

1. A miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern, characterized in that: It comprises a patch layer (2), a substrate layer (3) and a bottom surface layer (4) located at the upper and lower end surfaces of the patch layer (2), a feeding probe (5), and a symmetrically arranged snap-on device (1); The four-button fastening device (1) comprises a connecting card arranged on the bottom surface layer (4) and the patch layer (2), a PCB layer (17) in the substrate layer (3), and a base sheet layer (16) arranged at the upper and lower ends of the PCB layer (17); The PCB layer (17) includes a copper-clad conductor (174) and a switching diode (171), a resistor (172), and an inductor (173) connected in series in sequence in the copper-clad conductor (174). Metal via tubes (15) are installed at both upper and lower ends of the copper-clad conductor (174). Two metal via tubes (15) penetrate the substrate layer (16) and are respectively connected to two connecting clamps. The two connecting clamps control a DC bias voltage to turn the switching diode (171) on and off, thereby realizing switching of the antenna between a patch mode and a monopole mode.

2. The miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern according to claim 1, characterized in that: The patch layer (2) is located at the center of the top surface of the substrate layer (3), and its length is twice its width; the bottom surface layer (4) is located at the bottom surface of the substrate layer (3), and its size is the same as that of the bottom surface of the substrate layer (3) and is centrally symmetrical.

3. The miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern according to claim 1, characterized in that: The feeding probe (5) is located on the right side of the horizontal center line of the antenna, at a horizontal distance of 4.8 mm from the center point, and is a copper cylinder, with the top end connected to the patch layer (2) and the bottom end insulated from the bottom surface layer (4).

4. The miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern according to claim 1, characterized in that: The four-button device (1) is located on the horizontal center line of the antenna, symmetrically placed on the left and right, and the distance between the four-button device and the center point is 12 mm.

5. The miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern according to claim 1, characterized in that: The patch layer (2) and the bottom layer (4) are both made of conductive cloth material with a square resistance of 0.04Ω; the substrate layer is a foam material sheet with a thickness of 3.2mm, a relative dielectric constant of 1.06, and a loss tangent of 0.0001.

6. The miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern according to claim 1, characterized in that: Two connecting clips are arranged in mirror images, and the connecting clips include a male buckle, a female buckle (12) and a spring (18). The male buckle includes a male buckle ball head (11), a male buckle rod (13) and a male buckle base (14). The male buckle ball head (11) is connected to the male buckle base (14) through the male buckle rod (13), and the male buckle base (14) is in contact with the substrate layer (16). The spring (18) is a bent metal round bar, and the outer end point is connected to the inner side of the outer edge of the female buckle (12) by welding. The upper end of the spring (18) is connected to the male buckle ball head (11). The female buckles (12) of the two connecting clips are in contact with the patch layer (2) and the bottom surface layer (4) respectively.

7. The miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern according to claim 6, characterized in that: The PCB layer (17) is located at the center of the substrate layer (16), the two metal via tubes (15) are at the same height, and the metal via tubes (15) pass through the substrate layer (16) and are connected to the male buckle base (14).

8. The miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern according to claim 6, characterized in that: The substrate layer (16), the PCB layer (17), and the male buckle base (14) are of equal length.

9. The miniaturized wearable textile antenna with a fixed-frequency switchable directivity pattern according to claim 1, characterized in that: When the DC bias voltage is 0V, the switching diode (171) is disconnected, the snap-fit ​​device (1) is not connected to the patch layer (2) and the bottom layer (4), the antenna operates in a patch mode, and the radiation pattern has a single main lobe in the normal direction of the xy plane; When the DC bias voltage is 5V, the switching diode (171) is turned on, the snap-fit ​​device (1) serves as a short-circuit pin connecting the patch layer (2) and the bottom layer (4), the antenna operates in a monopole mode, and the dual main lobes of the radiation pattern are located between the xy plane and its normal direction.

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