Wearable Device

A wearable device includes a metal frame, a printed circuit board PCB, and a first feeding element, where a slot is formed between the metal frame and the PCB. The metal frame includes a first feed point, a first ground point, and a second ground point, and the metal frame is grounded at the first ground point and the second ground point. The metal frame is divided into a first area and a second area by the first ground point and the second ground point, and a circumferential length corresponding to the first area is greater than a circumferential length corresponding to the second area. The first feed point is disposed in the first area, and a distance between the first feed point and the first ground point along the metal frame is less than one third of the circumferential length corresponding to the first area.

This application claims priority to Chinese Patent Application No. 202010424295.0, filed with the China National Intellectual Property Administration on May 19, 2020 and entitled “WEARABLE DEVICE”, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This application relates to the field of wireless communication, and in particular, to a wearable device.

BACKGROUND

With the development of mobile communication technologies, a wearable device can monitor important data such as heartbeats and a sleep status of a human body at any time, and connect to the Internet by using a communication function, to complete data synchronization. Alternatively, the wearable device can obtain information such as a weather temperature. In addition, a built-in near field communication (near field communication, NFC) function enables a user to conveniently and easily consume by using the wearable device.

An important application of the foregoing wearable device cannot be implemented without the communication function, and a built-in antenna is required to transmit or receive electromagnetic signals. Currently, antenna forms such as a monopole antenna or an inverted-F antenna (inverted-F antenna, IFA) are generally used, and the antenna is placed around a printed circuit board (printed circuit board, PCB). Limited by a size of the wearable device (for example, a smartwatch), it is difficult for the built-in antenna of the wearable device to support all frequency bands in a fourth generation (fourth generation, 4G) mobile communication system.

SUMMARY

Embodiments of this application provide a wearable device. According to a slot antenna theory, a metal frame of the wearable device can be used to implement full-frequency band coverage in 4G communication. This provides good communication performance for the wearable device.

According to a first aspect, a wearable device is provided, including a printed circuit board PCB and an antenna structure. The antenna structure includes a metal frame and a first feeding element. A slot is formed between the metal frame and the PCB. The metal frame includes a first feed point, a first ground point, and a second ground point, and the metal frame is grounded at the first ground point and the second ground point. The metal frame is divided into a first area and a second area by the first ground point and the second ground point, and a circumferential length corresponding to the first area is greater than a circumferential length corresponding to the second area. The first feed point is disposed in the first area, and a distance between the first feed point and the first ground point along the metal frame is less than one third of the circumferential length corresponding to the first area. The first feeding element feeds at the first feed point for the antenna structure.

According to this technical solution in this embodiment of this application, the metal frame and the printed circuit board of the wearable device are used to form an antenna structure of the wearable device without increasing structural complexity of the wearable device. In this way, three resonances can be generated to cover all frequency bands in a 4G communication system.

With reference to the first aspect, in some implementations of the first aspect, the antenna structure is a slot antenna.

With reference to the first aspect, in some implementations of the first aspect, when the first feeding element is feeding, the antenna structure generates a first resonance, a second resonance, and a third resonance. A frequency of a resonance point of the first resonance is less than a frequency of a resonance point of the second resonance, and the frequency of the resonance point of the second resonance is less than a frequency of a resonance point of the third resonance.

According to this technical solution in this embodiment of this application, when the first feeding element is feeding, the antenna structure may generate the first resonance, the second resonance, and the third resonance. The first resonance, the second resonance, and the third resonance may respectively correspond to a low band, a middle hand, and a high band in the 4G communication system. When the first resonance is generated, the antenna structure may operate in a half-wavelength mode. When the second resonance is generated, the antenna structure may operate in a one-wavelength mode. When the third resonance is generated, the antenna structure may operate in a three-half-wavelength mode.

With reference to the first aspect, in some implementations of the first aspect, an operating frequency band of the antenna structure corresponding to the second resonance covers a global positioning system GPS frequency band.

According to the technical solution in this embodiment of this application, the second resonance may further cover a global positioning system frequency band, and a positioning antenna is also integrated into the metal frame of the wearable device, to provide a positioning service for the wearable device. This can further reduce complexity of an overall structure.

With reference to the first aspect, in some implementations of the first aspect, an operating frequency band of the antenna structure corresponding to the first resonance covers 698 MHz to 960 MHz, an operating frequency band of the antenna structure corresponding to the second resonance covers 1710 MHz to 2170 MHz, and an operating frequency band of the antenna structure corresponding to the third resonance covers 2300 MHz to 2690 MHz.

According to the technical solution in this embodiment of this application, the first resonance, the second resonance, and the third resonance may respectively correspond to a low band, a middle band, and a high band in the 4G communication system.

With reference to the first aspect, in some implementations of the first aspect, the wearable device further includes a band-pass filter. The metal frame further includes a third ground point, and the third ground point is disposed in the first area and located between the first feed point and the second ground point. One end of the band-pass filter is electrically connected to the metal frame at the third ground point, and the other end is grounded.

According to the technical solution in this embodiment of this application, a resonance point at which the antenna structure generates a resonance may be adjusted.

With reference to the first aspect, in some implementations of the first aspect, an operating frequency band of the band-pass filter covers an operating frequency band of the antenna structure corresponding to the third resonance.

According to the technical solution in this embodiment of this application, when the antenna operates in the operating frequency band corresponding to the third resonance, the band-pass filter may shorten a back-to-ground path of the band-pass filter, to improve radiation performance of the band-pass filter.

With reference to the first aspect, in some implementations of the first aspect, the band-pass filter is capacitive in an operating frequency band of the antenna structure corresponding to the first resonance or in an operating frequency band of the antenna structure corresponding to the second resonance.

According to the technical solution in this embodiment of this application, when the band-pass filter operates in a high band, the band-pass filter is capacitive for a low band and a middle band. Therefore, a capacitor in the band-pass filter may be disposed as an adjustable component, and may be configured to adjust the antenna structure to generate the first resonance and the second resonance to cover resonance points of a low band and a middle band in the 4G mobile communication system.

With reference to the first aspect, in some implementations of the first aspect, the operating frequency band of the band-pass filter covers 2300 MHz to 2690 MHz.

According to the technical solution in this embodiment of this application, the band-pass filter410may operate in a high band in the 4G mobile communication system.

With reference to the first aspect, in some implementations of the first aspect, a distance between the third ground point and the first ground point along the metal frame is one third of the circumferential length corresponding to the first area.

According to the technical solution in this embodiment of this application, a back-to-around path of the antenna structure when the antenna structure operates in the three-half-wavelength mode can be effectively shortened. When the antenna structure operates in a high band, interference caused by an environment near the metal frame can be reduced, and a radiation characteristic of the antenna structure when the antenna structure operates in the high band can be increased.

With reference to the first aspect, in some implementations of the first aspect, the circumferential length corresponding to the first area is a half of an operating wavelength corresponding to the resonance point of the first resonance.

According to the technical solution in this embodiment of this application, the circumferential length corresponding to the first area is a half of the operating wavelength corresponding to the resonance point of the first resonance, and a specific value tray be obtained through simulation.

With reference to the first aspect, in some implementations of the first aspect, the circumferential length corresponding to the first area is from 120 mm to 90 mm.

With reference to the first aspect, in some implementations of the first aspect, the circumferential length corresponding to the first area is 112 mm, 102 mm, or 97 mm.

According to the technical solution in this embodiment of this application, for a circular metal frame, when a surface diameter is 46 mm, the circumferential length corresponding to the first area250may be 112 mm; when a surface diameter is 42 mm, the circumferential length corresponding to the first area250may be 102 mm; or when a surface diameter is 40 mm, the circumferential length corresponding to the first area250may be 97 mm.

With reference to the first aspect, in some implementations of the first aspect, a central angle corresponding to the first area is from 288° to 252°.

According to the technical solution in this embodiment of this application, the central angle corresponding to the first area may be from 288° to 252°. A proportion of a radiator of the antenna structure to the metal frame is about 0.7 to 0.8.

With reference to the first aspect, in some implementations of the first aspect, the first area is made of a metal material, and the second area is made of a non-metal material.

According to the technical solution in this embodiment of this application, a slot between the second area and the PCB may be used to implement an electrical connection between a display of the wearable device and the PCB, or implement an electrical connection between a flexible circuit board and the PCB. Excessive cabling can be avoided, and a loss of the antenna structure can be reduced.

According to a second aspect, a wearable device is provided, including an antenna structure and a printed circuit board PCB. The antenna structure includes a metal frame, a band-pass filter, and a first feeding element, where a slot is formed between the metal frame and the PCB. The metal frame includes a first feed point, a first ground point, and a second ground point, and the metal frame is grounded at the first ground point and the second ground point. The metal frame is divided into a first area and a second area by the first ground point and the second ground point, and a circumferential length corresponding to the first area is greater than a circumferential length corresponding to the second area. The first feed point is disposed in the first area, a distance between the first feed point and the first ground point along the metal frame is less than one third of the circumferential length corresponding to the first area. The first feeding element feeds the antenna structure at the first feed point. The metal frame further includes a third ground point, and the third ground point is disposed in the first area and located between the first feed point and the second ground point. One end of the band-pass filter is electrically connected to the metal frame at the third around point, and the other end is grounded. An operating frequency band of the band-pass filter covers 2300 MHz to 2690 MHz, and a distance between the third ground point and the first ground point along the metal frame is one third of the circumferential length corresponding to the first area.

DESCRIPTION OF EMBODIMENTS

A wearable device provided in this application may be a portable device that can be integrated into clothes or accessories of a user, has a computing function, and can be connected to a mobile phone and various terminal devices. For example, the wearable device may be a watch, a smart wrist strap, a portable music player, a health monitoring device, a computing or game device, a smartphone, an accessory, or the like. In some embodiments, the wearable device is a watch that can be worn around a wrist of the user.

FIG.1is a schematic diagram of a structure of a wearable device according to this application. In some embodiments, the wearable device may be a watch or a band.

Refer toFIG.1. A wearable device100includes a main body101and one or more wrist straps102(FIG.1shows a part of an area of the wrist strap102). The wrist strap102is fixedly connected to the main body101, and the wrist strap102may be wound around a wrist, an arm, a leg, or another part of a body, to fasten the wearable device to the body of the user. As a central element of the wearable device100, the main body101may include a metal frame180and a display140. The metal frame180may surround the wearable device, and enclose the display140as a part of an appearance of the wearable device. Edges of the display140are adjacent to and fastened on the middle frame180, and are formed as a surface of the main body101. Accommodating space is formed between the metal frame180and the display140, and may accommodate a combination of a plurality of electronic components, to implement various functions of the wearable device100. The main body101further includes an input device120. The accommodating space between the metal frame180and the display140may accommodate a part of the input device120, and an exposed part of the input device120is convenient for a user to touch.

It may be understood that a shape of the metal frame180of the wearable device in this embodiment of this application may be a circle, a square, a polygon or another regular or irregular pattern. This is not limited herein. For brevity of description, the circular metal frame180is used as an example for description in the following embodiments.

As a surface of the main body101, the display140may be used as a protection board of the main body101, to avoid damage caused by exposure of a component accommodated in the metal frame180. For example, the display140may include a liquid crystal display (liquid crystal display, LCD) and a protection part, and the protection part may be made of a sapphire crystal, glass, plastic, or another material. The protection part of the display may be integrated with the metal frame by using thermoplastic plastic (PC/ABS).

The user may interact with the wearable device100by using the display140. For example, the display140may receive an input operation of the user, and make corresponding output in response to the input operation. For example, the user may choose (or in another manner) to open or edit a graph by touching or pressing a position of the graph on the display140.

The input device120is attached to the outside of the metal frame180and extends to the inside of the metal frame180. In some embodiments, the input device includes a head121and a rod part122that are connected. The rod part122extends into the housing180, and the head121is exposed outside the housing180, and may be used as a part in contact with the user, to allow the user to touch the input device, and receive an input operation of the user by rotating, translating, tilting, or pressing the head121. When the user operates the head121, the rod part122may move along with the head121. It may be understood that the head121may be in any shape. For example, the head121may be in a cylindrical shape. It may be understood that the rotatable input device120may be referred to as a button. In an embodiment in which the wearable device100is a watch, the rotatable input device120may form a crown of the watch, and the input device120is referred to as a crown.

In this application, a related design is made for the input device120, and one or more functions are integrated into the input device120, to improve user experience. This is described in detail below.

It may be understood that the input device120is not limited to the structure shown inFIG.1, and any mechanical part that can receive an input operation of a user may be used as the input device in this application.

The wearable device100includes a button1202. As an example of the input device120, the wearable device100may allow the user to perform an input operation by pressing, moving, or tilting the button1202. For example, the button1202may be mounted on a side surface180-A of the metal frame180, a part of the button1202is exposed, and the other part extends from the side surface of the metal frame180toward the inside of the housing180(not shown in the figure). For example, the button1202may alternatively be disposed on the head121of the button1201, and a pressing operation may also be performed when a rotation operation is performed. For example, the button1202may alternatively be disposed on a top surface on which a display140is mounted on the main body101.

Still refer toFIG.1, in some other embodiments, the wearable device100may include a button1201and the button1202. The button1201and the button1202may be disposed on a same surface of the metal frame180, for example, both are disposed on a same side surface of the metal frame180. Alternatively, the button1201and the button1202may be disposed on different surfaces of the metal frame180. This is not limited in this application. It may be understood that the wearable device100may include one or more buttons1202, or may include one or more buttons1201.

It should be understood that the wearable device cannot be implemented without a communication function, and a built-in antenna is required to transmit or receive an electromagnetic signal. Currently, an antenna form such as a monopole antenna and an IFA is generally used. Limited by a size of the wearable device (for example, a smartwatch), it is difficult for a built-in antenna of the wearable device to support all frequency bands in a 4G mobile communication system.

Embodiments of this application provide an antenna design solution of a wearable device. A metal frame of the wearable device may be used to implement a low band (low band, LB) (698 MHz to 960 MHz), a middle band (middle band, MB) (1710 MHz to 2170 MHz), and a high band (high band, HB) (2300 MHz to 2690 MHz) in the 4G communication system, to provide good communication performance for the wearable device.

FIG.2is a schematic diagram of an antenna structure of a wearable device according to this application.

As shown inFIG.2, the wearable device may include a PCB220and an antenna structure200, and the antenna structure may include a metal frame210and a first feeding element230.

A slot240is formed between the metal frame210and the PCB220. The metal frame210may include a first feed point201, a first ground point211, and a second ground point212. The metal frame210may be grounded at the first ground point211and the second ground point212. The metal frame210is divided into a first area250and a second area260by the first ground point211and the second ground point212, and a circumferential length corresponding to the first area250is greater than a circumferential length corresponding to the second area260. The first feed point201may be disposed in the first area250and close to the first ground point211. A distance between the first feed point201and the first ground point211along the metal frame210is less than one third of the circumferential length corresponding to the first area250. The first feeding element230feeds the antenna structure at the first feed point201. The circumferential length corresponding to the first area250may be considered as a relatively long distance from the first ground point211to the second ground point212along a surface of the metal frame210. The circumferential length corresponding to the second area260may be considered as a relatively short distance from the first ground point211to the second ground point212along the surface of the metal frame210.

Optionally, the antenna structure200may be a slot antenna.

It should be understood that the PCB220is formed by press-fitting a plurality of layers of substrates and a metal plating layer exists in the plurality of layers of substrates, and may be used as a ground plane of the antenna structure. The metal frame210may be disposed around the PCB220.

Optionally, the first area250of the metal frame210may be made of a metal material, and the second area260may be made of a non-metal material.

Optionally, the first feeding element230may be disposed on the PCB220, and may be a power chip in the wearable device.

Optionally, the wearable device may further include at least one tuning component, which may be disposed at the first ground point211or the second ground point212, and is configured to adjust an operating frequency of the antenna structure.

Optionally, a central angle corresponding to the first area250may be from 288° to 252°. A proportion of a radiator of the antenna structure to the metal frame210is about 0.7 to 0.8.

Optionally, the circumferential length corresponding to the first area may be from 120 mm to 90 min.

Optionally, for a circular metal frame, when a surface diameter is 46 mm, the circumferential length corresponding to the first area250may be 112 mm; when a surface diameter is 42 mm, the circumferential length corresponding to the first area250may be 102 mm, or when a surface diameter is 40 mm, the circumferential length corresponding to the first area250may be 97 mm. It should be understood that the circumferential length corresponding to the first area250may be adjusted based on a design or simulation. This is not limited in this application.

Optionally, a slot between the second area260and the PCB220may be used to implement an electrical connection between a display of the wearable device and the PCB220, or implement an electrical connection between a flexible circuit board (flexible printed circuit, FPC) and the PCB220. Excessive cabling can be avoided, and a loss of the antenna structure can be reduced.

FIG.3is an S parameter simulation result of the antenna structure shown inFIG.2.

As shown inFIG.3, when the first feeding element is feeding, the antenna structure may generate a first resonance, a second resonance, and a third resonance.

The first resonance may be a resonance generated when the antenna structure operates in a half-wavelength mode, and corresponds to the LB in the 4G communication system. The second resonance may be a resonance generated when the antenna structure operates in a one-wavelength mode, and corresponds to the MB in the 4G communication system. The third resonance may be a resonance generated when the antenna structure operates in a three-half-wavelength mode, and corresponds to the HB in the 4G communication system.

It should be understood that the antenna structure provided in the technical solution provided in this embodiment of this application uses a concept of volume multiplex, so that each resonance can fill the antenna structure. A parasitic stub may be further additionally disposed on the basis of this solution, so that a new resonance mode can be excited, and an operating frequency bandwidth of the antenna can be further expanded.

Optionally, the second resonance may further cover a global positioning system (global positioning system, GPS) frequency band, and a positioning antenna is also integrated into the metal frame of the wearable device, to provide a positioning service for the wearable device. This can further reduce complexity of an overall structure.

Optionally, an operating frequency band corresponding to the antenna structure may also cover a frequency band corresponding to a global system of mobile communication (global system of mobile communication, GSM) or code division multiple access (code division multiple access, CDMA), or may cover a frequency band corresponding to a wideband code division multiple access (wideband code division multiple access, WCDMA), a universal mobile telecommunication system (universal mobile telecommunication system UMTS), a worldwide interoperability for microwave access (worldwide interoperability for microwave access, WiMAX) communication system, a general packet radio service (general packet radio service, GPRS), or the like. It should be understood that the technical solution provided in this application may also be applied to 5G communication. This is not limited in this application.

FIG.4is a schematic diagram of electric field strength distribution of an antenna structure according to an embodiment of this application.

As shown inFIG.2, the metal frame210may be expanded from the first ground point211to form the structure inFIG.4. That is, two ends of the metal frame210in the structure inFIG.4are connected to form a circular structure inFIG.2.

As shown inFIG.4, the first feed point201may be disposed at a near-ground position, that is, a strong-current area/a weak electric field area of the metal frame. The antenna structure may generate a plurality of resonances that operate in frequency multiplication. For example, the antenna structure may operate in a half-wavelength mode, a one-wavelength mode, a three-half-wavelength mode, a two-wavelength mode, or the like.

Optionally, when the first area250of the metal frame210is made of a metal material, and the second area260is made of a non-metal material, an electronic component may be disposed at a joint between the first area250and the second area260, that is, an electronic component may be further disposed at the first ground point211, and a resonance point of a resonance generated by the antenna structure is adjusted by capacitance or inductance of the electronic component. For example, an inductor may be disposed at the first ground point211, one end of the inductor is connected to the metal frame210at the first ground point211, and the other end is grounded, so that the resonance point of the resonance of the antenna structure can be reduced.

Optionally, an electronic component may be disposed at the second ground point212, so that a resonance point of a resonance generated by the antenna structure may be adjusted. For example, an inductor may be disposed at the second ground point212, one end of the inductor is connected to the metal frame210at the second ground point212, and the other end is grounded, so that the resonance point of the resonance of the antenna structure can be reduced.

FIG.5toFIG.7are schematic diagrams of electric field strength distribution of an antenna structure operating in each mode according to an embodiment of this application.FIG.5is a schematic diagram of electric field distribution in a slot when an antenna structure operates in a half-wavelength mode.FIG.6is a schematic diagram of electric field distribution in a slot when an antenna structure operates in a one-wavelength mode.FIG.7is a schematic diagram of electric field distribution in a slot when an antenna structure operates in a three-half-wavelength mode.

FIG.5toFIG.7are schematic diagrams of electric field strength distribution on a slot formed between a PCB and a metal frame in each operating mode. A dark-colored area in the figure is a position of an electric field null, and may correspond to a point at which current is most intense on the metal frame.

Optionally, an electronic component, such as a capacitor or an inductor, may be loaded or unloaded at a strong current point corresponding to each mode, and a resonance point of a resonance corresponding to each mode may be fine-tuned.

FIG.8is a schematic diagram of another antenna structure of a wearable device according to this application.

As shown inFIG.8, the wearable device further includes a second feeding element310. The metal frame210may further include a second feed point301. The second feed point301may be disposed in the first area250, and is located between the first feed point201and the second ground point212. The second feeding element310may feeds the antenna structure at the second feed point.

Optionally, a distance between the second feed point301and the first ground point211along the metal frame210is a half of a circumferential length corresponding to the first area250. That is, as shown inFIG.4, the second feed point301may be disposed at an electric field null in the one-wavelength mode. When the second feeding element310feeds at the second feed point301, the second feeding element310may excite a half-wavelength mode and a three-half-wavelength mode of the antenna structure, which correspond to the LB and the HB in the 4G communication system. It should be understood that the wearable device may include a band-pass filter that is configured to generate an MB, so that an operating frequency band of the antenna structure covers the 4G communication system.

FIG.9andFIG.10are schematic diagrams of a structure of still another antenna structure of a wearable device according to this application.FIG.9is a schematic diagram of a structure of a wearable device according to an embodiment of this application.FIG.10is a stretch-out view of a metal frame according to an embodiment of this application.

As shown inFIG.9, the wearable device further includes a band-pass filter410.

The metal frame210may further include a third ground point401. The third ground point401is disposed in the first area250, and is located between the first feed point201and the second ground point212. One end of the band-pass filter410is electrically connected to the metal frame210at the third ground point401, and the other end is grounded.

Optionally, the band-pass filter410may be disposed on the PCB220, and is electrically connected to the metal frame210at the third ground point401by using a metal spring plate,

Optionally, an operating frequency band of the band-pass filter410covers 2300 MHz to 2690 MHz. That is, the band-pass filter410may operate in an HB in a 4G mobile communication system.

Optionally, a distance between the third ground point401and the first ground point211along the metal frame210is one third of a circumferential length corresponding to the first area250. As shown inFIG.10, the third ground point401is a point, at which current is most intense, of an antenna structure when the antenna structure operates in a three-half-wavelength mode. This can effectively shorten a back-to-ground path of the antenna structure when the antenna structure operates in the three-half-wavelength mode, and reduce interference caused by an environment near the metal frame.

FIG.11shows a simple band-pass filter structure. It should be understood that a specific form of the band-pass filter is not limited in this embodiment of this application. The band-pass filter may include an inductor411and a capacitor412. Operating at an HB, the band-pass filter is capacitive for an LB and an MB. Therefore, the capacitor412may be disposed as an adjustable component, and may be configured to adjust the antenna structure to generate a first resonance and a second resonance to cover resonance points of the LB and the MB in a 4G mobile communication system.

Optionally, the wearable device may further include a switch component that is disposed between the band-pass filter and the third ground point. The switch component may be used to select a corresponding band-pass filter when different resonances are generated by the antenna structure, so that resonance points corresponding to the resonances generated by the antenna structure may be adjusted.

FIG.12is a schematic diagram of a structure of a feeding solution of antenna structure according to an embodiment of this application.

As shown inFIG.12, a feeding element of a wearable device may be disposed on the PCB220, and is electrically connected to a feed point on the metal frame210by using a spring plate501.

Optionally, the spring plate501may be directly electrically connected to each feed point, or may perform coupled feeding. This is not limited in this application.

It should be understood that the technical solution provided in this embodiment of this application may be further applied to a ground structure of an antenna structure, and is connected to a ground plane by using a spring plate. Alternatively, each electronic component on the PCB may be electrically connected to the metal frame by using a spring plate.