Wearable button antenna

Abstract

The invention provides a wearable button antenna, and relates to the technical field of wireless communication, the wearable button antenna comprises an antenna substrate, one side of the antenna substrate is provided with a radiation patch, the other side of the antenna substrate is provided with a ground plane, and the radiation patch is electrically connected to the ground plane; the body surface fabric is arranged on the body surface of the organism to be detected; and the rigid coaxial cable is arranged between the ground plane and the body surface fabric and is used for electrically connecting the ground plane to the body surface fabric. The wearable button antenna is a hard antenna, becomes an ideal choice for wireless body area network communication due to the characteristics of compact structure and easy integration, and is compact in structure, small in size, low in manufacturing cost, stable in performance and not prone to damage.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a wearable button antenna. Background Art

[0002] A body area network (BAN) is a communication network operating near, on, or within the human body (but not limited to the human body). It utilizes a suite of compact, low-power, and intelligent sensors to monitor information about the human body and its surroundings. To address the application needs of BANs in the healthcare and information and communications industries, experts in wireless personal area networks (WPANs) have developed relevant technical standards. BANs can be categorized as wearable or implantable, depending on the device's operating area. Furthermore, because BANs communicate near or within the human body, BAN systems require low transmit power, low power consumption, a low profile, compactness, integration into fabrics, and minimal impact on the device's performance. With the rapid development of wireless body area networks (WBANs), wearable wireless electronic devices are becoming increasingly common in our daily lives. Wearable devices can monitor our physiological health, ensuring timely alerts and prompt medical attention when health issues arise.

[0003] At present, textile fabrics and conductive fabrics are mostly used as dielectric substrates and radiation patches of antennas. The softness of the materials makes the mechanical stability of the antenna poor, which in turn causes the performance of the antenna to deteriorate when it is deformed. The antenna has poor working stability and is easy to be damaged. Summary of the Invention

[0004] The present invention provides a wearable button antenna to solve the problems of poor working stability and easy damage of antennas in related technologies.

[0005] The present invention provides a wearable button antenna, comprising: an antenna substrate, wherein a radiation patch is provided on one side of the antenna substrate and a ground plane is provided on the other side of the antenna substrate, and the radiation patch is electrically connected to the ground plane; Body surface fabric, placed on the body surface of the organism to be detected; A rigid coaxial cable is disposed between the ground plane and the body surface fabric, and is used to electrically connect the ground plane to the body surface fabric.

[0006] According to a wearable button antenna provided by the present invention, the radiation patch is connected to the ground plane via a short-circuit post to form a PIFA antenna structure for generating off-body directional radiation; And / or, the ground plane is connected to the body surface fabric via the rigid coaxial cable to form a monopole-like structure for generating horizontal omnidirectional radiation.

[0007] In an embodiment of the present invention, a wearable button antenna may include at least one of a PIFA antenna structure and a monopole-like structure. Specifically, the radiating patch on one side of the antenna substrate is connected to the ground plane on the other side of the antenna substrate through a short-circuit post, together forming a PIFA antenna structure, which can generate high-gain high-frequency band out-of-body directional radiation. The antenna radiates in a direction perpendicular to the surface of the biological body to be detected to achieve in-vitro communication. In addition, the ground plane on the other side of the antenna substrate is connected to the surface fabric through a rigid coaxial cable, together forming a monopole-like structure, which can generate low-frequency band horizontal omnidirectional radiation. The antenna is polarized vertically along the surface of the biological body to be detected to achieve surface communication. In the wearable button antenna of the present application, the PIFA antenna structure and the monopole-like structure are cleverly combined together, which not only realizes dual-band and dual-mode, but also meets the requirement of small size.

[0008] According to a wearable button antenna provided by the present invention, the body surface fabric includes a conductive fabric and a textile fabric; The conductive fabric is arranged on a side away from the surface of the organism to be detected for electrical connection with the rigid coaxial cable, and the textile fabric is arranged on a side close to the surface of the organism to be detected for contact with the surface of the organism to be detected.

[0009] In an embodiment of the present invention, a specific implementation of a body surface fabric is provided. The specific body surface fabric may include conductive fabric and textile fabric. The conductive fabric, together with a coaxial cable and a ground plane, can form a monopole-like structure, specifically an inverted top-loaded monopole antenna, which is used to generate horizontal omnidirectional radiation for use in body surface communications. The conductive fabric can also serve as a shielding layer to prevent the antenna from being affected by the detected organism and causing frequency shift, ensuring that the antenna maintains normal operating performance when integrated with the detected organism. Furthermore, the conductive fabric can be adhered to textile fabrics such as clothing. The soft conductive fabric integrated into clothing will reduce discomfort to the detected organism.

[0010] According to a wearable button antenna provided by the present invention, the frequency band of the off-body directional radiation generated by the PIFA antenna structure is higher than the frequency band of the horizontal omnidirectional radiation generated by the monopole-like structure.

[0011] According to a wearable button antenna provided by the present invention, a first notch is provided on the radiation patch, and the first notch is used to adjust the impedance of the button antenna to assist in matching the impedance of the button antenna with the impedance of the rigid coaxial cable.

[0012] In the embodiment of the present invention, a first notch is provided on the radiation patch to improve the impedance matching of the antenna, thereby achieving a comprehensive improvement in power efficiency, signal quality, and device safety.

[0013] According to a wearable button antenna provided by the present invention, an inclined surface is provided on one side of the bottom of the first notch.

[0014] In the embodiment of the present invention, the provision of the oblique slot helps to further improve the impedance matching of the antenna.

[0015] According to a wearable button antenna provided by the present invention, a second notch is further provided on the radiation patch, and the second notch is used to extend the current path of the high-frequency band to adjust the high-frequency band in which the off-body directional radiation generated by the button antenna is located.

[0016] In an embodiment of the present invention, a second notch is further provided on the above-mentioned radiation patch, which is used to extend the current path in the high-frequency band to adjust the high-frequency band of the off-body directional radiation generated by the button antenna so that it is within the communication frequency band specified by the communication standard.

[0017] According to a wearable button antenna provided by the present invention, the second notch is configured as a rectangular slot, and one side of the rectangular slot opening is provided with a protrusion facing the other side to semi-close the rectangular slot.

[0018] In the embodiment of the present invention, the special structure of the semi-enclosed rectangular slot is to change the current path in the high frequency band, and specifically to improve the cross-polarization of the 5.8 GHz resonance point in the high frequency band.

[0019] According to a wearable button antenna provided by the present invention, a parasitic patch is also provided on one side of the antenna substrate where a radiation patch is provided, and the parasitic patch does not contact the radiation patch. The parasitic patch and the radiation patch are coupled to adjust the impedance of the button antenna to assist in matching the impedance of the button antenna with the impedance of the rigid coaxial cable.

[0020] In an embodiment of the present invention, a parasitic patch is also provided on the antenna substrate. The parasitic patch and the radiating patch are not in contact with each other, but the two are coupled to adjust the impedance of the button antenna to assist in matching the impedance of the button antenna with the impedance of the rigid coaxial cable, thereby improving the impedance matching of the antenna and achieving a comprehensive improvement in power efficiency, signal quality, and equipment safety.

[0021] According to a wearable button antenna provided by the present invention, a protrusion is further provided on the side of the radiation patch close to the parasitic patch, which serves as a first coupling part; the parasitic patch is U-shaped, and the U-shaped part serves as a second coupling part, and the first coupling part is coupled to the second coupling part.

[0022] In an embodiment of the present invention, a specific implementation method for coupling between a radiating patch and a parasitic patch is provided. Specifically, a protrusion is provided on one side of the radiating patch near the parasitic patch, serving as a first coupling portion. The parasitic patch is U-shaped, and the U-shaped portion serves as a second coupling portion. The first coupling portion and the second coupling portion are coupled to achieve coupling between the radiating patch and the parasitic patch, thereby improving the impedance matching of the antenna.

[0023] The wearable button antenna provided by the present invention is compared with the related art that uses textile fabrics and conductive fabrics as the dielectric substrate and radiation patch of the antenna. The soft antenna is easy to deform, which leads to problems such as poor antenna performance, poor working stability, and easy damage. The wearable button antenna provided by the present application is a hard antenna. Due to its compact structure and easy integration characteristics, it becomes an ideal choice for wireless body area network communication. In the button antenna provided by the present application, the surface fabric is arranged on the surface of the organism to be detected and is connected to the antenna substrate through a rigid coaxial cable. Radiation patches and ground planes are respectively provided on both sides of the antenna substrate. Radiation patches and ground planes are electrically connected to each other to emit radiation. The button antenna has a compact structure, small size, low cost, stable performance, and is not easy to damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present invention or related technologies, the following is a brief introduction to the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 1 is a schematic structural diagram of a wearable button antenna provided by the present invention; Figure 2 is a top view of the antenna substrate in the wearable button antenna provided by the present invention; Figure 3 is a bottom view of the antenna substrate in the wearable button antenna provided by the present invention; Figure 4 This is a schematic diagram of the structure of the wearable button antenna provided by the present invention arranged on the surface of human tissue; Figure 5 is the radiation pattern of the wearable button antenna provided by the present invention in the YOZ plane at 2.45 GHz; Figure 6 is the radiation pattern of the wearable button antenna provided by the present invention in the XOY plane at 2.45 GHz; Figure 7 is the radiation pattern of the wearable button antenna provided by the present invention in the XOZ plane at 5.8 GHz; Figure 8is the radiation pattern of the wearable button antenna provided by the present invention in the YOZ plane at 5.8 GHz; Figure 9 : This is an S-parameter curve diagram of the wearable button antenna provided by the present invention in a free space state and under a loaded human tissue model; Figure 10 This is a SAR curve diagram of the wearable button antenna provided by the present invention when loaded with a human tissue model at 2.45 GHz.

[0026] Reference numerals: 100: antenna substrate; 200: body surface fabric; 300: rigid coaxial cable; 101: Radiating patch; 102: Ground plane; 103: Short-circuit post; 104: Parasitic patch; 201: Conductive fabric; 202: Textile fabric; 1: First notch; 2: Second notch; 3: Skin; 4: Fat; 5: Muscle; 6: First mounting hole; 7: Second mounting hole; 8: Third mounting hole; 9: Feed hole; 10: irregular rectangular patch; A: protrusion; B: first coupling portion; C: second coupling portion. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be clarified that the terms "vertical", "transverse", "longitudinal", "front", "rear", "left", "right", "up", "down", "horizontal", etc. indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not mean that the device or element referred to must have a specific orientation or position. Therefore, they cannot be understood as limiting the present invention.

[0029] In the description of the present invention, it should also 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 may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections; they may refer to direct connections, indirect connections through an intermediate medium, internal connections between two components, and wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0030] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] In related technologies, soft and easily deformable textile fabrics and conductive fabrics are often used as the dielectric substrate and radiation patch of the antenna. However, the softness of the material will cause the performance of the antenna to deteriorate when it is deformed.

[0032] To address these issues, the present applicant discovered that button antennas, as rigid antennas, are ideal for wireless body area network communications due to their compact structure and ease of integration. Therefore, the present applicant proposed a wearable button antenna to address the issue of performance being easily affected by deformation due to the softness of the antenna material.

[0033] The wearable button antenna of the present invention will be described below with reference to the accompanying drawings.

[0034] An embodiment of the present invention provides a wearable button antenna. Figure 1 : is a schematic structural diagram of the wearable button antenna provided by the present invention, Figure 2 is a top view of the antenna substrate in the wearable button antenna provided by the present invention, Figure 3 FIG. 1 is a bottom view of the antenna substrate in the wearable button antenna provided by the present invention, as shown in FIG. Figures 1 to 3 As shown, the wearable button antenna includes: An antenna substrate 100 , wherein a radiation patch 101 is provided on one side of the antenna substrate 100 , and a ground plane 102 is provided on the other side of the antenna substrate 100 , wherein the radiation patch 101 is electrically connected to the ground plane 102 ; The body surface fabric 200 is provided on the body surface of the organism to be detected; A rigid coaxial cable 300 is disposed between the ground plane 102 and the body surface fabric 200 , and is used to electrically connect the ground plane 102 to the body surface fabric 200 .

[0035] It should be noted that the antenna substrate 100 can serve as a carrier of the antenna, and is used to support the radiation patch 101 and the ground plane 102 .

[0036] In some embodiments, the antenna substrate 100 may be F4BM220, which has a dielectric constant of 2.2 and a loss tangent of 0.0009. This is only an example and is not a limitation in this application.

[0037] It should also be noted that the radiating patch 101 is the antenna's primary radiating element and is, for example, a copper sheet. Its shape (e.g., rectangular, circular, etc.) and size determine parameters such as the antenna's resonant frequency and radiation direction. Furthermore, the design of radiating patch 101 also influences the polarization (e.g., linear, circular, etc.) and radiation pattern (directional or omnidirectional).

[0038] It should also be noted that the above-mentioned ground plane 102 is, for example, a copper sheet; the above-mentioned ground plane 102 serves as the metal base layer of the antenna, and its functions are divided into two parts: 1) its function in the low-frequency band is to act as a series capacitive load to improve the impedance matching in the low-frequency band; 2) its function in the high-frequency band is to act as a reflector of the PIFA structure, reflecting the radiation in the high-frequency band and generating directional radiation.

[0039] In other embodiments, a specific implementation method of placing a wearable button antenna on human tissue is provided. Figure 4 FIG is a schematic diagram of the structure of the wearable button antenna provided by the present invention arranged on the surface of human tissue, as shown in FIG. Figure 4 As shown, skin 3, fat 4 and muscle 5 are equivalent to the human body structure, and the body surface fabric 200 of the wearable button antenna is used to be set above the skin 3 and can be in contact with the human skin 3.

[0040] In the wearable button antenna provided in an embodiment of the present invention, compared with the related art that uses textile fabrics and conductive fabrics as the dielectric substrate and radiation patch of the antenna, the soft antenna is easy to deform, which leads to problems such as poor antenna performance, poor working stability, and easy damage. The wearable button antenna provided in this application is a hard antenna. Due to its compact structure and easy integration characteristics, it becomes an ideal choice for wireless body area network communication. In the button antenna provided in this application, the surface fabric 200 is arranged on the surface of the organism to be detected and is connected to the antenna substrate 100 through a rigid coaxial cable 300. A radiation patch 101 and a ground plane 102 are respectively provided on both sides of the antenna substrate 100. The radiation patch 101 and the ground plane 102 can emit radiation through electrical connection. The button antenna has a compact structure, small size, low cost, stable performance, and is not easy to damage.

[0041] In some embodiments, as Figures 1 to 3 As shown, the radiation patch 101 is connected to the ground plane 102 via a short-circuit post 103 to form a PIFA (Planar Inverted-F Antenna) antenna structure for generating off-body directional radiation; And / or, the ground plane 102 is connected to the body surface fabric 200 via the rigid coaxial cable 300 to form a monopole-like structure for generating horizontal omnidirectional radiation.

[0042] Specifically, the radiation patch 101 is connected to the ground plane 102 through the short-circuit post 103 to form a PIFA antenna structure. PIFA is a miniaturized antenna structure used in mobile communication devices. Its core feature is that it achieves a balance between compact size and high-efficiency performance through a unique geometric design. It can generate high-gain in vitro directional radiation, and the radiation direction is perpendicular to the body surface of the organism to be detected to achieve in vitro communication.

[0043] In addition, the ground plane 102 is connected to the surface fabric 200 through a rigid coaxial cable 300, which can form a monopole-like structure. The monopole-like structure is a radiation structure evolved from a monopole antenna or has similar functions. Its core feature is that it relies on the outer conductor of the rigid coaxial cable 300 to connect the ground plane 102 and the conductive fabric to form a monopole radiation structure, which is specifically used to generate horizontal omnidirectional radiation. The radiation is vertically polarized along the surface of the biological body to be detected to achieve surface communication.

[0044] In some embodiments, the frequency band of the off-body directional radiation generated by the constructed PIFA antenna structure is higher than the frequency band of the horizontal omnidirectional radiation generated by the constructed monopole-like structure.

[0045] For example, the frequency band of the off-body directional radiation generated by the PIFA antenna structure can be 5.8 GHz, which is used for in vitro transmission; the frequency band of the horizontal omnidirectional radiation generated by the monopole-like structure can be 2.45 GHz, which is used for human body detection. This is just an example and this application does not impose any restrictions on this.

[0046] In an embodiment of the present invention, a wearable button antenna may include at least one of a PIFA antenna structure and a monopole-like structure. Specifically, the radiation patch 101 on one side of the antenna substrate 100 is connected to the ground plane 102 on the other side of the antenna substrate 100 through a short-circuit post 103, together forming a PIFA antenna structure, which can generate high-gain high-frequency band out-of-body directional radiation. The antenna radiates in a direction perpendicular to the surface of the biological body to be detected to achieve in-vitro communication; in addition, the ground plane on the other side of the antenna substrate is connected to the surface fabric through a rigid coaxial cable, together forming a monopole-like structure, which can generate low-frequency band horizontal omnidirectional radiation. The antenna is vertically polarized along the surface of the biological body to be detected to achieve surface communication. In the wearable button antenna of the present application, the PIFA antenna structure and the monopole-like structure are cleverly combined together, achieving dual-band and dual-mode while also meeting the requirement of a small size.

[0047] In some embodiments, a specific implementation of the body surface fabric 200 is provided. Figures 1 to 3 As shown, the body surface fabric 200 includes a conductive fabric 201 and a textile fabric 202; the conductive fabric 201 is arranged on a side away from the body surface of the organism to be detected, and is used to be electrically connected to the rigid coaxial cable 300, and the textile fabric 202 is arranged on a side close to the body surface of the organism to be detected, and is used to contact the body surface of the organism to be detected.

[0048] For example, a layer of 3 mm thick textile fabric 202 can be set at a distance of 10.5 mm below the antenna substrate 100. The relative dielectric constant of the textile fabric 202 is, for example, 1.4, and the dielectric loss tangent is 0.044. The upper layer of the textile fabric 202 is covered with a layer of conductive fabric 201, such as SHIELDIT™ SUPER, which has a conductivity of 1.18×105 S / m and a thickness of 0.17 mm. The conductive fabric 201 is connected to the radiation patch below the dielectric substrate through the outer conductor of the coaxial cable.

[0049] In an embodiment of the present invention, the specific body surface fabric 200 may include a conductive fabric 201 and a textile fabric 202, wherein the conductive fabric 201 can form a monopole-like structure together with the rigid coaxial cable 300 and the ground plane 102, specifically forming an inverted top-loaded monopole antenna for generating horizontal omnidirectional radiation for use in body surface communication; the conductive fabric 201 can also serve as a shielding layer to prevent the antenna from being affected by the organism to be detected and causing frequency shift, thereby ensuring that the antenna can maintain normal operating performance when integrated with the organism to be detected; in addition, the conductive fabric 201 can be adhered to textile fabrics 202 such as clothing, and the soft conductive fabric 201 integrated on clothing will reduce the discomfort of the organism to be detected.

[0050] In some embodiments, as Figure 2 As shown, a first notch 1 is formed on the radiation patch 101 , and the first notch 1 is used to adjust the impedance of the button antenna to help the impedance of the button antenna match the impedance of the rigid coaxial cable 300 .

[0051] In some embodiments, as Figure 2 As shown, an inclined surface is provided on one side of the bottom of the first notch 1 .

[0052] Specifically, providing the oblique slots helps to further improve the impedance matching of the antenna.

[0053] In the embodiment of the present invention, the radiation patch 101 is provided with a first notch 1 for improving the impedance matching of the antenna, thereby achieving a comprehensive improvement in power efficiency, signal quality, and device safety.

[0054] In some embodiments, as Figure 2As shown, the radiation patch 101 is further provided with a second notch 2, which is used to extend the current path of the high-frequency band to adjust the high-frequency band of the off-body directional radiation generated by the button antenna.

[0055] It should be noted that extending the current path within the area of ​​the limited radiation patch 101 equivalently increases the electrical length, shifting the high-frequency resonance point toward the low frequency, which helps to expand the high-frequency bandwidth.

[0056] In some embodiments, a specific implementation of the second notch 2 is provided. Figure 2 As shown, the second notch 2 is configured as a rectangular slot, and a protrusion A facing the other side is provided on one side of the rectangular slot opening to semi-close the rectangular slot.

[0057] Specifically, the special structure of the semi-enclosed rectangular slot is to change the current path in the high frequency band, and specifically to improve the cross-polarization of the 5.8 GHz resonance point in the high frequency band.

[0058] In an embodiment of the present invention, a second notch 2 is further provided on the radiation patch 101 for extending the current path in the high-frequency band to adjust the high-frequency band of the off-body directional radiation generated by the button antenna so that it is within the communication frequency band specified by the communication standard.

[0059] In some embodiments, as Figure 2 As shown, a parasitic patch 104 is also provided on one side of the antenna substrate 100 where the radiation patch 101 is provided. The parasitic patch 104 does not contact the radiation patch 101. The parasitic patch 104 and the radiation patch 101 are coupled to adjust the impedance of the button antenna to assist in matching the impedance of the button antenna with the impedance of the rigid coaxial cable 300.

[0060] In an embodiment of the present invention, a parasitic patch 104 is further provided on the antenna substrate 100. The parasitic patch 104 is not in contact with the radiation patch 101, but the two are coupled to adjust the impedance of the button antenna to assist in matching the impedance of the button antenna with the impedance of the rigid coaxial cable 300, thereby improving the impedance matching of the antenna and achieving a comprehensive improvement in power efficiency, signal quality, and equipment safety.

[0061] In some embodiments, a specific implementation of the coupling between the radiation patch 101 and the parasitic patch 104 is provided. Figure 2 As shown, a protrusion is further provided on one side of the radiation patch 101 close to the parasitic patch 104, serving as a first coupling portion B; the parasitic patch is U-shaped, and the U-shaped portion serves as a second coupling portion C, and the first coupling portion B is coupled to the second coupling portion C.

[0062] In an embodiment of the present invention, a protrusion is further provided on one side of the radiating patch 101 close to the parasitic patch 104, which serves as a first coupling portion B. The parasitic patch is U-shaped, and the U-shaped portion serves as a second coupling portion C. The first coupling portion B and the second coupling portion C are coupled to achieve coupling between the radiating patch 101 and the parasitic patch 104, thereby improving the impedance matching of the antenna.

[0063] In some embodiments, as Figure 2 and Figure 3 As shown, a first mounting hole 6 is further provided on the radiating patch 101, and a corresponding second mounting hole 7 is also provided on the grounding surface 102. The two ends of the short-circuit column 103 are respectively connected to the radiating patch 101 and the grounding surface 102 through the first mounting hole 6 and the second mounting hole 7, so as to connect the radiating patch 101 and the grounding surface 102.

[0064] It should be noted that the first mounting hole 6 and the second mounting hole 7 are, for example, short-circuit holes.

[0065] In other embodiments, Figure 3 As shown, a third mounting hole 8 is further provided on the ground plane 102 , and one end of the rigid coaxial cable 300 can be installed in the third mounting hole 8 to be electrically connected to the ground plane 102 .

[0066] It should be noted that the third mounting hole 8 is, for example, a grounding hole.

[0067] The wearable button antenna provided by an embodiment of the present invention is described below by way of example.

[0068] The existing related technologies generally have the following problems: 1) Traditional antennas mostly support a single frequency band and are unable to meet dual-band communication requirements; 2) The bandwidth is narrow and is susceptible to interference when worn on the human body; 3) Poor mechanical stability, bending or extrusion can easily lead to performance degradation; 4) The radiation pattern is fixed and cannot take into account both surface communication (omnidirectional) and external connection (broadside); 5) When the antenna is close to the human body, the impedance matching deteriorates, and the Specific Absorption Rate (SAR) value must be strictly controlled to ensure safety.

[0069] To address these challenges, a button antenna that can operate efficiently in both the 2.45 GHz and 5.2 GHz bands and exhibits excellent robustness is urgently needed. To effectively address these challenges, the present invention implements a compact, dual-band, dual-mode wearable button antenna that effectively addresses these issues and provides a high-performance wearable antenna.

[0070] Specifically, if Figures 1 to 4As shown, an embodiment of the present invention provides a small-sized, low-cost, and stable-performance dual-band, dual-mode button-type antenna suitable for body area networks. In the low-frequency band of 2.45 GHz, it acts as a monopole to generate omnidirectional radiation that can be used for surface communication; in the high-frequency band of 5.8 GHz, it acts as a PIFA (planar inverted F) antenna to generate directional radiation suitable for off-body communication, cleverly combining the two antenna structures while ensuring the requirement of a small size.

[0071] To achieve the above objectives, the present invention provides a hard material wearable button antenna, comprising an antenna substrate 100, a rigid coaxial cable 300, a body surface fabric 200, and a ground plane 102; The impedance of the rigid coaxial cable 300 is 50 ohms (Ω), which is acceptable within a certain tolerance range.

[0072] The size of the button antenna is 13mm*13mm*1.5mm, and it presents a regular square frame. The antenna substrate 100 of the button antenna is F4BM220, with a dielectric constant of 2.2 and a loss tangent of 0.0009. The upper and lower layers of the antenna substrate 100 both have radiation patches (the upper layer is considered to be the above-mentioned radiation patch 101, and the lower layer is considered to be the ground plane 102). There is a 3mm thick textile fabric 202 at a distance of 10.5mm below the substrate. The textile fabric 202 has a relative dielectric constant of 1.4 and a dielectric loss tangent of 0.044. The upper layer of the textile fabric 202 is covered with a layer of conductive fabric 201, such as SHIELDIT™ SUPER, with a conductivity of 1.18×105 S / m, with a thickness of 0.17mm. The conductive fabric 201 is connected to the radiation patch below the antenna substrate 100 (that is, the above-mentioned ground plane 102) through the outer conductor of the rigid coaxial cable 300. The upper radiation patch of the antenna substrate 100 (that is, the above-mentioned radiation patch 101) is connected to the lower radiation patch (that is, the above-mentioned ground plane 102) through the short-circuit column 103. At the same time, there is a parasitic patch 104 on the upper layer of the antenna substrate 100, which does not contact other radiation patches 101, thereby forming a button antenna.

[0073] The button antenna's upper radiating patch (also known as radiating patch 101) features slots on both sides of the rectangular patch. The oblique slot on the left side (also known as the first slot 1) improves the antenna's impedance matching, while the irregular rectangular slot on the right side (also known as the second slot 2) extends the current path in the high-frequency band. A parasitic patch 104, similar to a U-shaped structure, is located next to radiating patch 101 to further improve impedance matching. The left side of radiating patch 101 is connected to a shorting post 103 via a branch. The lower side of shorting post 103 is further connected to a ground plane 102 located in the middle of the dielectric plate via a curved branch. The connection between radiating patch 101 and ground plane 102 via shorting post 103 forms a PIFA antenna structure, generating high-gain, off-body directional radiation. The outer conductor of the rigid coaxial cable 300 is connected to both the ground plane 102 and the conductive fabric 201, forming a quasi-monopole structure, producing a horizontal omnidirectional radiation pattern suitable for on-body communication.

[0074] Therefore, the embodiment of the present invention adopts the above-mentioned wearable button antenna design, the input impedance of the feeding point is a standard 50Ω, and the conductive fabric 201 is used as a shielding layer to prevent the antenna from being affected by the human body and causing frequency shift, ensuring that the antenna can still maintain normal operating performance when integrated with the human body.

[0075] In addition, if Figures 1 to 4 As shown, the embodiment of the present invention is a dual-band mode button antenna suitable for body area network, which combines a wearable button antenna with a button on clothing. The designed button antenna can be easily integrated into clothing. Figure 1 and Figure 2 The front view and top view of the antenna are shown. Figure 3 This is a top view of the antenna back substrate. Viewed from the top of antenna substrate 100, the antenna's radiating patch 101 is connected to the ground plane 102 at the bottom of antenna substrate 100 via shorting posts 103, forming a PIFA antenna. Simultaneously, a parasitic patch 104 on top of antenna substrate 100 improves the antenna's impedance matching by coupling with radiating patch 101. Radiating patch 101 is slotted, forming a first slot 1 and a second slot 2. Radiating patch 101 also has a feed hole 9, through which a rigid coaxial cable 200 can be inserted for power supply. The first and second mounting holes 6 and 7 are shorting holes used to connect radiating patch 101 to ground plane 102 via shorting posts 103. Parasitic patch 104 is an L-shaped coupling patch partially connected to an irregular rectangular patch 10.

[0076] Looking at the antenna as a whole, the button-shaped antenna substrate 100 is connected via a rigid coaxial cable 300. The bottom of the rigid coaxial cable 300 is also connected to the conductive fabric 201 and the textile fabric 202. The ground plane 102 at the bottom of the antenna substrate 100 is connected to the rigid coaxial cable 300 and the conductive fabric 201 via the third mounting hole 8, forming an inverted top-loaded monopole antenna.

[0077] The embodiment of the present invention is a button antenna applied to the wearable field, so Figure 4 The performance of a button antenna placed on human tissue is simulated, using skin 3, fat 4, and muscle 5 as equivalent to the human body structure. Low-frequency omnidirectional radiation is used to detect human body data, and high-frequency directional radiation is used to transmit and process the data detected by the antenna to an external receiving device.

[0078] The embodiment of the present invention is a dual-band, dual-mode button antenna for use in the body area network field. In order to better integrate it into the human body, a small square button antenna is invented. The button antenna can be integrated into clothing through a rigid coaxial cable 300, and the rigid coaxial cable 300 can serve as a support. The conductive fabric 201 can be adhered to the clothing. The soft conductive fabric 201 integrated into the clothing will reduce discomfort.

[0079] The advantages of the embodiments of the present invention are: 1) It is small in size, and the rigid antenna is not easily damaged or deformed. It has a simple structure and can be integrated into the human body. It is low in cost and can achieve excellent performance requirements in both low and high frequency bands.

[0080] 2) Resonance was achieved at 2.45 GHz and 5.8 GHz, with return loss below -10 dB at both frequencies. The 2.45 GHz frequency was used for human body detection, while the 5.8 GHz frequency was used for in vitro transmission.

[0081] Figure 5 is the radiation pattern of the wearable button antenna provided by the present invention on the YOZ plane at 2.45 GHz, Figure 6 is the radiation pattern of the wearable button antenna provided by the present invention in the XOY plane at 2.45 GHz, such as Figure 5 and Figure 6 As shown, this is the radiation pattern of the wearable button antenna at 2.45 GHz. Focusing on the main polarization curve in the figure, it can be seen that the radiation pattern of the antenna is similar to the radiation characteristics of a monopole. It mainly radiates in a direction parallel to the human body and shows good omnidirectionality in the XOY plane. The maximum gain is about 4.2 dBi. The antenna is polarized vertically along the surface of the human body. At this time, the antenna is suitable for surface communication.

[0082] Figure 7is the radiation pattern of the wearable button antenna provided by the present invention on the XOZ plane at 5.8 GHz, Figure 8 is the radiation pattern of the wearable button antenna provided by the present invention on the YOZ plane at 5.8 GHz, such as Figure 7 and Figure 8 As shown, this is the radiation pattern of the wearable button antenna at 5.8 GHz. Focusing on the main polarization curve in the figure, it can be seen that the antenna radiates in a direction perpendicular to the human body with a maximum gain of about 9 dBi, which is used for in vitro communication.

[0083] Figure 9 is an S parameter curve diagram of the wearable button antenna provided by the present invention in the free space state and loaded human tissue model, such as Figure 9 As shown in FIG, the upper and lower frequency bands of the embodiment of the present invention in free space have working bandwidths of 2.4-2.6 GHz and 5.3-8.4 GHz respectively. Since the embodiment of the present invention is applied to the human body, the impact of electromagnetic radiation on the human body must be considered, such as Figure 9 As shown, the return loss of the embodiment of the present invention on the human tissue structure is slightly offset in the lower frequency band compared to that in free space, but the impact is not significant, the impedance matching becomes better in the upper frequency band, and the covered bandwidth range is larger than that in free space.

[0084] Figure 10 SAR curve of the wearable button antenna provided by the present invention when loaded with a human tissue model at 2.45 GHz, as shown in FIG. Figure 10 As shown, the SAR value of the embodiment of the present invention at 2.45 GHz and 5.8 GHz is less than 0.6 W / kg, meeting the international standard.

[0085] In the description provided above, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0086] Furthermore, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are also intended to fall within the scope of protection of the present invention and form different embodiments. For example, in the above embodiments, those skilled in the art will be able to use them in combination based on the known technical solutions and the technical problems to be solved by this application.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A wearable button antenna, characterized in that: include: an antenna substrate, wherein a radiation patch is provided on one side of the antenna substrate and a ground plane is provided on the other side of the antenna substrate, and the radiation patch is electrically connected to the ground plane; Body surface fabric, placed on the body surface of the organism to be detected; A rigid coaxial cable is disposed between the ground plane and the body surface fabric, and is used to electrically connect the ground plane to the body surface fabric.

2. The wearable button antenna according to claim 1, characterized in that The radiation patch is connected to the ground plane via a short-circuit post to form a PIFA antenna structure for generating off-body directional radiation; And / or, the ground plane is connected to the body surface fabric via the rigid coaxial cable to form a monopole-like structure for generating horizontal omnidirectional radiation.

3. The wearable button antenna according to claim 2, characterized in that The body surface fabric includes conductive fabric and textile fabric; The conductive fabric is arranged on a side away from the surface of the organism to be detected for electrical connection with the rigid coaxial cable, and the textile fabric is arranged on a side close to the surface of the organism to be detected for contact with the surface of the organism to be detected.

4. The wearable button antenna according to claim 2 or 3, characterized in that: The frequency band of the off-body directional radiation generated by the constructed PIFA antenna structure is higher than the frequency band of the horizontal omnidirectional radiation generated by the constructed monopole-like structure.

5. The wearable button antenna according to any one of claims 1 to 3, characterized in that: A first notch is formed on the radiation patch, and the first notch is used to adjust the impedance of the button antenna to assist in matching the impedance of the button antenna with the impedance of the rigid coaxial cable.

6. The wearable button antenna according to claim 5, characterized in that An inclined surface is provided on one side of the bottom of the first notch.

7. The wearable button antenna according to claim 5, characterized in that The radiation patch is further provided with a second notch, which is used to extend the current path in the high-frequency band to adjust the high-frequency band in which the off-body directional radiation generated by the button antenna is located.

8. The wearable button antenna according to claim 7, characterized in that: The second notch is configured as a rectangular slot, and a protrusion facing the other side is provided on one side of the rectangular slot opening to semi-close the rectangular slot.

9. The wearable button antenna according to claim 5, characterized in that A parasitic patch is also provided on one side of the antenna substrate where the radiation patch is provided. The parasitic patch does not contact the radiation patch. The parasitic patch and the radiation patch are coupled to adjust the impedance of the button antenna to assist in matching the impedance of the button antenna with the impedance of the rigid coaxial cable.

10. The wearable button antenna according to claim 9, characterized in that: A protrusion is further provided on a side of the radiation patch close to the parasitic patch, serving as a first coupling portion; the parasitic patch is U-shaped, and the U-shaped portion serves as a second coupling portion, and the first coupling portion is coupled to the second coupling portion.

Images