CN111628283A

CN111628283A - Antenna structure and wearable equipment

Info

Publication number: CN111628283A
Application number: CN202010525769.0A
Authority: CN
Inventors: 赵安平
Original assignee: Anhui Huami Information Technology Co Ltd
Current assignee: Anhui Huami Information Technology Co Ltd
Priority date: 2020-06-10
Filing date: 2020-06-10
Publication date: 2020-09-04

Abstract

The utility model relates to an electronic equipment technical field specifically provides an antenna structure and wearable equipment. Wearable equipment includes metal casing, and the casing includes drain pan and encircles drain pan edge a week and the frame of being connected with the drain pan integral type, antenna structure includes: the gap is arranged on the frame and provided with a first end and a second end which are positioned on two opposite sides in a first direction, and the first direction is a direction which surrounds the edge of the bottom shell for one circle; the first end of the gap is provided with an opening, and the opening faces to one side away from the bottom shell; 1/4, the length from the first end of the slot to the ground terminal is the operating wavelength in the first direction; and the feed terminal is arranged between the first end of the gap and the grounding terminal and is positioned at a position close to the grounding terminal. The antenna structure of the present disclosure has a smaller slot length and better structural strength and appearance integrity of the housing.

Description

Antenna structure and wearable equipment

Technical Field

The utility model relates to an electronic equipment technical field, concretely relates to antenna structure and wearable equipment.

Background

With the development of electronic devices, smart wearable devices are increasingly popular with multiple users due to their diverse functions. Taking a smart watch as an example, a general smart watch integrates a plurality of functions such as motion assistance, track positioning, connection with an intelligent terminal and the like in addition to a basic timing function. To achieve these functions, a built-in antenna is required in the smart watch to receive and radiate signals. For example, to receive GPS signals, a watch requires a GPS positioning antenna; for another example, the watch also needs a bluetooth antenna for information interaction and connection with a mobile phone, and the like.

With the development of wearable devices, more and more smart watches employ all-metal housings. The all-metal shell is that the bottom shell and the middle frame of the watch are made of metal materials. In particular, the all-metal shell may be formed by integrally molding the bottom shell and the metal middle frame, or may be electrically connected together by using a connection method such as a screw. The metal shell has better protective capability, and the appearance quality and the grade of the watch are greatly improved. However, the all-metal case also shields the internal antenna of the wristwatch, and this makes it difficult to design the antenna, and therefore, how to design the all-metal case antenna is an important research direction.

Disclosure of Invention

To realize the antenna design of all metal casing in the wearable equipment, this disclosed embodiment provides an antenna structure and wearable equipment.

In a first aspect, the present disclosure provides an antenna structure applied to a wearable device, where the wearable device includes a metal casing, the casing includes a bottom casing and a frame surrounding a periphery of the bottom casing and integrally connected to the bottom casing, and the antenna structure includes:

the gap is arranged on the frame and provided with a first end and a second end which are positioned at two opposite sides in a first direction, and the first direction is a direction surrounding the edge of the bottom shell for one circle; the first end of the gap is provided with an opening, and the opening faces to one side away from the bottom shell; 1/4, the length from the first end of the slot to the ground terminal is the operating wavelength in the first direction;

and the feed terminal is arranged between the first end of the gap and the grounding terminal and is positioned at a position close to the grounding terminal.

In some embodiments, the second end of the slot forms the ground terminal.

In some embodiments, the antenna structure further includes:

and the ground terminal is arranged in the gap and positioned between the first end and the second end, the gap is divided into a first sub-gap and a second sub-gap which are independent in the first direction by the ground terminal, and the ground terminal forms the ground terminal.

In some embodiments, a groove is opened on an outer side wall of the second end of the slit, and the groove is symmetrical to the opening shape in the first direction.

In some embodiments, the gap is filled with a shape-fitting injection-molded structure, and the injection-molded structure is a non-metallic material.

In some embodiments, the antenna structure further comprises:

the first capacitor is arranged in the gap, and two poles of the first capacitor are respectively and correspondingly connected to two sides of the gap in the width direction; in the first direction, the first capacitor is located at one end close to the opening.

In some embodiments, in the first direction, the distance between the feeding terminal and the ground terminal is a first length, the distance between the first end and the ground terminal is a second length, and a ratio of the first length to the second length is 0.1-0.2.

In a second aspect, embodiments of the present disclosure provide a wearable device including an antenna structure according to any of the embodiments of the first aspect.

In some embodiments, the antenna comprises a bluetooth antenna and a satellite positioning antenna, wherein the bluetooth antenna and the satellite positioning antenna are of the antenna structures and are respectively arranged on two opposite sides of the frame;

the first gap of the Bluetooth antenna and the second gap of the satellite positioning antenna are symmetrical in shape, the length from the first end of the first gap to the grounding end is 1/4 of the working wavelength of the Bluetooth antenna, and the length from the first end of the second gap to the grounding end is 1/4 of the working wavelength of the satellite positioning antenna.

In some embodiments, the wearable device is a smart watch or a smart bracelet.

The antenna structure that this disclosed embodiment provided is applied to wearable equipment, and wearable equipment includes the all metal casing that the integral type is connected, and antenna structure is including seting up the gap on the frame, and the gap has relative first end and second end in the first direction, and the first direction is the direction of encircleing of frame, and the gap is equipped with the opening at first end to the opening orientation deviates from one side of drain pan, and the feed terminal sets up between the first end in gap and earthing terminal, and is located the position department that is close to the earthing terminal. The slot antenna is formed by arranging the slot on the frame and is suitable for all-metal shells. And an opening is arranged at one end of the slot, so that the feeding and the slot form an 1/4-wavelength slot antenna, namely, the length of the slot in the first direction is 1/4 of the working wavelength, and the length of the slot opening is greatly shortened. On the one hand furthest remains the metal outward appearance, and on the other hand is because the gap is littleer, and the shell wholeness is better, and the dustproof and waterproof grade of the improve equipment of being convenient for satisfies miniaturized wearable equipment simultaneously and uses.

The antenna structure provided by the embodiment of the present disclosure may form a ground terminal by the second end of the slot, or may form a ground terminal by disposing a ground terminal in the slot. Therefore, the antenna switching of different wavelengths, such as the switching of a Bluetooth antenna and a satellite positioning antenna, can be realized by adjusting the position of the grounding terminal. And under the condition that the shell comprises a plurality of antenna slots, the wiring terminals are utilized to realize the antenna structures with different wavelengths under the same slot shape, so that the appearance integrity of the equipment is better.

The antenna structure that this disclosed embodiment provided, seted up the recess on the lateral wall of the second end of gap, the recess is symmetrical with the opening shape on the first direction, is guaranteeing through the recess under the unchangeable condition of antenna performance for the gap structure is more symmetrical from the outward appearance, improves user experience. And fill non-metallic material's injection structure in the gap, seal the gap, realize the dustproof and waterproof of equipment to it is the casing to keep the outward appearance unanimous, promotes user experience.

The antenna structure provided by the embodiment of the present disclosure further includes a first capacitor, two poles of the first capacitor are respectively and correspondingly connected to two sides of the slot in the width direction, and in the first direction, the first capacitor is located at one end close to the opening. Through set up the electric capacity in the gap, increase the effective electric length of gap, under same operating frequency promptly, the required gap length of antenna is shorter, further reduces antenna structure occupation space.

According to the antenna structure provided by the embodiment of the disclosure, in the first direction, the ratio of the distance between the feed terminal and the ground terminal to the distance between the first end and the ground terminal is 0.1-0.2, so that the feed terminal is closer to the ground terminal, and the gap length is most effectively utilized. In addition, the return loss (or matching degree) of the antenna can be optimized by adjusting the distance between the feed point and the ground terminal, and when the feed terminal is positioned close to the ground terminal, the matching of the antenna is most easily adjusted to be optimal, thereby improving the performance of the antenna.

The wearable device provided by the embodiment of the present disclosure includes the antenna structure of any one of the above embodiments, and therefore has all the above advantages. And equipment includes bluetooth and satellite positioning antenna, and preferably two antennas can be the symmetry respectively and set up in the relative both sides of frame to keep equipment structure symmetry in the follow outward appearance, have good impression, improve user experience.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1a is a schematic structural diagram of a wearable device according to some embodiments of the present disclosure.

Fig. 1b is a schematic structural view of a housing of a wearable device according to some embodiments of the present disclosure.

Fig. 2 is a schematic diagram of an antenna structure in accordance with some embodiments of the present disclosure.

Fig. 3 is a schematic diagram of an antenna structure according to further embodiments of the present disclosure.

Fig. 4 is a schematic diagram of an antenna structure in accordance with further embodiments of the present disclosure.

Fig. 5 is a schematic illustration of a fill structure in accordance with still further embodiments of the present disclosure.

Fig. 6 is a graph of return loss for an antenna structure in accordance with some embodiments of the present disclosure.

Fig. 7 is a graph of antenna efficiency for an antenna structure in accordance with some embodiments of the present disclosure.

Fig. 8 is a schematic diagram of an antenna structure according to further embodiments of the present disclosure.

Detailed Description

The technical solutions of the present disclosure will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only some embodiments of the present disclosure, but not all embodiments. All other embodiments, which can be derived by one of ordinary skill in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure. In addition, technical features involved in different embodiments of the present disclosure described below may be combined with each other as long as they do not conflict with each other.

The antenna structure provided by the embodiment of the disclosure is suitable for wearable equipment with an all-metal shell. In smart wearable devices, various antennas are often included, such as a bluetooth antenna for establishing a connection with a smartphone; also for example a GPS antenna for positioning; for example, an LTE antenna used for implementing base station communication, and the like, the device radiates or receives signals to the outside through the antenna.

Taking a smart watch as an example, the smart watch generally can realize functions such as motion assistance, trajectory positioning, and the like, and therefore generally includes at least one bluetooth antenna and one satellite positioning antenna. In a watch with a common plastic shell, an internal antenna can directly radiate and receive signals outwards, the antenna structure is easy to design, electromagnetic signals can be shielded with the increase of metal in the shell, and the design requirement of the antenna structure is higher and higher.

For example, the middle frame part of part wrist-watch adopts the metal middle frame, and the drain pan adopts non-metallic material such as plastic, and the antenna accessible metal middle frame and the gap of mainboard realize this moment to both sides outwards radiate the signal about passing through the middle frame. And when the wrist-watch adopted all metal casing, for example watch case's drain pan and center adopt metal material integrated into one piece, because the drain pan also is the metal material, the unable rethread mainboard of antenna and the gap of center are to toward radiation for built-in antenna's the design degree of difficulty greatly increased.

In the related art, in order to implement an antenna structure with an all-metal case, in some watches, a middle frame is provided with a circular gap from the middle, the middle frame is divided into two independent upper and lower parts, a slot antenna is formed by the circular gap on the middle frame, and a signal is radiated outward by the slot antenna. The structure needs to completely divide the metal middle frame, and non-metal materials are injected into the annular gap to form an integral appearance and seal, so that the structural strength and the dustproof and waterproof performance are greatly reduced, the gap length surrounds the watch for one circle, the gap appearance is sharp after the gap is filled and injected, the integrity is poor, and the watch appearance and the watch grade are reduced.

In order to solve the above-mentioned drawbacks in the related art, in a first aspect, embodiments of the present disclosure provide an antenna structure.

The antenna structure of the present disclosure can be used as various types of antennas in a device, such as a bluetooth antenna, a GPS antenna, an LTE antenna, etc., where the volume of the device allows. The wearable device related to the present disclosure may also be any device type suitable for implementation, such as a wrist-worn device like a smart watch or a smart bracelet; also, head-mounted devices such as smart headsets, smart glasses, and the like; wearable devices such as smart apparel; etc., to which the present disclosure is not limited.

For convenience of description, in the following embodiments of the present disclosure, the wearable device is exemplified by a smart watch. As shown in fig. 1a, the smart watch includes a case 100 and a screen 600 provided at an open end of a front surface of the case 100. As shown in fig. 1b, the casing 100 includes a bottom shell 110 and a rim 120, the rim 120 surrounds the periphery of the bottom shell to form a side middle frame, and the bottom shell 100 and the rim 120 are made of metal and are integrally formed. Of course, the housing structure shown in fig. 1b is only an example, and in other embodiments, there may be other metal housings with any shapes and structures, for example, the bottom housing 110 and the bezel 120 may be fixedly connected by screws or the like to form an integrated structure. Those skilled in the art should appreciate that this disclosure is not enumerated.

In some embodiments, the antenna structure of the present disclosure includes a slot opened on the bezel 120, and the slot has a first end and a second end opposite to each other in a first direction, where the first direction is a direction in which the bezel 120 surrounds the bottom chassis 110 for a circle. The slot is provided with an opening at the first end, and the opening is towards the side of deviating from the drain pan, and in the first direction, the length of first end to antenna ground terminal is 1/4 of operating wavelength. The antenna structure further comprises a feed terminal, one end of the feed terminal is connected to the feed module on the equipment mainboard, the other end of the feed terminal stretches across the gap and is located between the first end and the grounding end and close to the grounding end, and therefore electromagnetic wave signals radiated outwards through the gap are obtained.

Through the above, the antenna structure of the all-metal shell is realized by the slot antenna, so that the antenna structure is suitable for the wearable equipment of the metal shell, and the strength and the appearance integrity of the equipment are improved. The slot antenna is arranged on the side frame 120, so that when the device is worn, an antenna signal is prevented from being blocked, and the signal strength is improved. Through setting up the opening at first end for in the antenna structure, the feed forms 1/4 wavelength's slot antenna with the gap, and the length of gap on the first direction shortens to working wavelength's 1/4 promptly, compares the correlation technique and can dwindle the gap length by one time, reduces the open-ended length, and furthest has remain the metal outward appearance, and the dustproof and waterproof grade of improve equipment is also convenient for in littleer gap, satisfies miniaturized wearable equipment simultaneously and uses.

One embodiment of the antenna structure of the present disclosure is shown in fig. 2, and the antenna structure of the present disclosure is described in detail below with reference to fig. 2.

For convenience of description, a direction in which the frame 120 surrounds the edge of the bottom casing 110 is defined as a "first direction", and it is understood that the "first direction" refers to a surrounding direction of the surface of the frame 120, for example: when the frame 120 is circularly surrounded, the "first direction" refers to a surrounding direction of the circle, and the "length in the first direction" is the length of the arc; when the frame 120 has a rounded rectangular structure as shown in fig. 1b, the "first direction" refers to a surrounding direction of the rounded rectangle, and the "length in the first direction" is the length of the surrounding rectangle. In the embodiment shown in fig. 2, the illustrated left-right direction is the first direction of the frame 120, and it should be understood by those skilled in the art that the description thereof is omitted.

As shown in fig. 2, in the present embodiment, the antenna structure includes a slot 210 opened on the bezel 120, and the slot 210 has a first end 121 and a second end 122 opposite to each other in the first direction. The slit 210 refers to a through hole penetrating the sidewall of the bezel 120. The first end of the slit 210 is provided with an opening 220, the opening 220 is a notch that opens one end of the slit 210, the opening 220 also needs to penetrate through the sidewall of the bezel 120, and the opening direction of the opening 220 faces to the side away from the bottom case 110, i.e. the direction facing upward in the figure, so that the structure formed by the opening 220 and the slit 210 is as shown in fig. 2.

A feeding module is disposed on the main board inside the housing 100, and the feeding module is configured to form electromagnetic waves with different resonant frequencies, so that the antenna structure formed by the feeding terminal 300 and the slot 210 radiates outwards. The basic principles of the antenna will be understood by those skilled in the art and the description of the disclosure will not be repeated. The feed terminal 300 is provided between the first end 121 and the second end 122 across the width direction of the slot 210, and is close to the second end 122.

Based on the principle of slot antenna, it is known that feeding power between the grounding points at the two ends of the slot is equivalent to forming a dipole antenna with 1/2 wavelength, and the length of the slot is 1/2 of the operating wavelength. In the present embodiment, an opening 220 is provided at a first end of the slot 210, the slot 210 with the opening 220 and the power supply terminal 300 form a monopole antenna with a wavelength of 1/4, and the length L of the slot 210 is 1/4 of the operating wavelength. To the antenna of the same kind of function, the antenna structure of this embodiment can reduce aperture length L of gap 210 by one time, is applicable to comparatively miniaturized wearable equipment, for example intelligent bracelet, intelligent earphone etc..

Specifically, the length L of the slot 210 in the first direction should be equal to 1/4 wavelengths of one resonant frequency of the radiated electric wave. For the different functions realized by the antenna structure, the radiation bands are different, for example, the center operating frequency of the bluetooth antenna is 2.44GHz, while the center operating frequency of the civil GPS satellite positioning antenna is generally 1.575GHz, so the length L of the slot 210 can be calculated according to different resonant frequencies. The relationship between the slot 210 length L and the operating frequency f of the electromagnetic wave is expressed as:

in the formula (1), L represents the length of the slot 210 in the first direction, λ represents the wavelength of the electromagnetic wave, C represents the speed of light, and f represents the resonant frequency of the electromagnetic wave. As can be seen from equation (1), the length L of the slot 210 is inversely proportional to the operating frequency f of the antenna, i.e., the lower the operating frequency of the antenna, the longer the required slot length.

As can be seen from the above description, when the device includes two or more antenna structures with different operating frequencies, the lengths of the slots 210 on the frame 120 are different. This results in the device not being able to achieve a symmetrical structure in appearance, and as electronic devices have been developed, appearance has long been an important consideration for people to choose electronic devices. Therefore, the present disclosure further provides embodiments that can further ensure the consistency of the appearance of the device while reducing the gap.

For convenience of explanation, in this embodiment, a bluetooth antenna and a satellite positioning antenna are taken as examples. As can be seen from the foregoing, the center working frequency of the Bluetooth antenna is 2.44GHz, and the center working frequency of the civil GPS satellite positioning antennaThe general frequency is 1.575GHz, and the slot length L of the Bluetooth antenna can be calculated by using the formula (1)₁Gap length L with satellite positioning antenna₂The relationship between, expressed as:

according to the formula (2), the gap length of the Bluetooth antenna is about 0.65 times of the gap length of the GPS satellite positioning antenna, if the Bluetooth antenna and the GPS satellite positioning antenna are arranged on two sides of the shell relatively, the difference of the opening gaps of the Bluetooth antenna and the GPS satellite positioning antenna is large, the appearance of the equipment is disordered due to the asymmetrical gaps, and the appearance of a user and the grade of the equipment are greatly reduced.

In the present embodiment, the satellite positioning antenna has a structure as shown in fig. 2, and the length from the first end 121 to the second end 122 of the slot 210 is L₂. When designing a bluetooth antenna, referring to fig. 3A, the length from the first end 121 to the second end 122 of the slot 210 is still L₂Consistent with a satellite positioning antenna. In the bluetooth antenna, a ground terminal 400 is further included, the ground terminal 400 is disposed in the slot 210 between the first end 121 and the second end 122, and the ground terminal 400 spans the width of the slot 210, thereby dividing the slot 210 into two sub-slots on the left and right sides.

The feeding terminal 300 is disposed between the first end 121 and the ground terminal 400 and is close to the ground terminal 400. The ground terminal 400 functions to move the ground terminal of the slot antenna to the position of the ground terminal 400, so that the antenna can be adjusted to be suitable for different operating frequencies by changing the position of the ground terminal 400 in the first direction of the slot 210.

As shown in fig. 3A, in the present embodiment, the distance L from the first end 121 to the ground terminal 400 may be set₁＝0.65L₂So that the length from the first end 121 to the ground terminal 400, which is equivalent to 1/4 wavelengths of the bluetooth antenna, realizes the bluetooth antenna radiation. The embodiment of fig. 3A may be equivalent to the antenna structure of fig. 3B.

In this embodiment, by adjusting the position of the ground terminal 400 in the slot 210, antenna structures with different operating wavelengths can be realized, so that antenna structures with different functions can be realized without changing the length of the opening of the slot 210. For example, when the device includes a bluetooth antenna and a satellite positioning antenna, the two antennas may be separately opened at opposite sides of the device, and the slot may be completely symmetrically formed in shape, and the operating length of the bluetooth antenna is adjusted by using the ground terminal 400, so that the device may be more uniform and symmetrical in appearance.

Of course, those skilled in the art will understand that the antenna structure of the present disclosure is not limited to the two examples, and the device antenna is not limited to include only the two examples, and may have any other form suitable for implementation, which is not enumerated here. In addition, under the condition that the requirements on the consistency and symmetry of the appearance of the device are not high, different antenna functions can be realized by directly forming the slots with different lengths, and the present disclosure also does not limit the functions.

Further, referring to the antenna structures in fig. 2 and fig. 3, it can be known that one of the inventive concepts of the antenna structure of the present disclosure is that: an opening 220 is opened at one end of slot 210 to form an 1/4 wavelength slot antenna similar to a monopole, shortening the aperture length of slot 210. As can be seen from the illustration, the structure of the opening 220 also makes the antenna structure asymmetric in the first direction, which affects the uniformity of the appearance of the device. Therefore, the present disclosure further provides some embodiments, based on the above inventive concept, to further improve the consistency and symmetry of the appearance of the device.

As shown in fig. 4, in some embodiments, a groove 230 is cut into an outer sidewall of the second end 122 of the slot 210. As shown in fig. 4A, the groove 230 is symmetrical in shape to the opening 220 in the first direction, but as shown in fig. 4B, the groove 230 is opened only on the surface of the bezel 120 without penetrating through the thickness direction of the bezel 120. Thus, after injection molding the slot, the slot 210 is completely symmetrical in the first direction, and the groove 230 is a non-through groove, which does not change the length and the distribution of the openings of the slot 210, and thus does not have any performance impact on the original antenna structure.

After the antenna structure is formed, the slot needs to be filled by injection molding, for example, a filling method of nano injection molding is adopted, and the slot is filled with a non-metallic nano material. On one hand, the gap is sealed, the dustproof and waterproof grade of the equipment is improved, and on the other hand, the wavelength of a radiation signal is shortened when the radiation signal propagates in a medium material, so that the opening length of the gap can be further reduced by using a filling medium.

Taking the embodiment of fig. 4 as an example, the appearance of the filled nano material is as shown in fig. 5, and it can be seen that, in the first direction, the shape of the slit opening is completely symmetrical, and the appearance consistency of the shell is better. Of course, those skilled in the art will appreciate that the groove 230 need not be provided where the requirements for uniformity and symmetry of the device appearance are not high, and the present disclosure is not limited thereto.

It is also worth noting that the wavelength of the cell wave in the medium decreases with increasing dielectric constant, so that the gap length can be reduced by using a filler material with a high dielectric constant. However, since a dielectric having an excessively large dielectric constant lowers the bandwidth and radiation efficiency of the antenna, a material having a dielectric constant of about 3.0 is preferable in this embodiment. Taking a satellite positioning antenna with a frequency of 1.575GHz as an example, in the present embodiment, the slot length can be controlled to be about 33mm, and the length of the aperture capable of being slotted can be greatly shortened.

According to the above embodiment, the antenna structure of the present disclosure is applicable to a wearable device of a metal shell, and an opening is provided at one end of the slot, so that the feed and the slot form an 1/4-wavelength slot antenna, and the length of the slot opening is greatly shortened. And through ground terminal, under the condition that does not change gap trompil length, realize the antenna structure of different functions, realize antenna structure symmetry in the first direction through the recess, the outward appearance uniformity of equipment is better.

Further, antenna structures in other embodiments of the present disclosure are shown in fig. 8. In this embodiment, the effective electrical length of the slot antenna is increased by providing a capacitor in the slot, and the length of the slot is further decreased at the same resonant frequency. This will be described in detail with reference to fig. 8.

As shown in fig. 8, in this embodiment, the antenna structure further includes a first capacitor 500, and the first capacitor 500 is connected across the slot 210, that is, two poles of the first capacitor 500 are electrically connected to two sides of the slot 210 in the width direction.

It should be noted that, in the embodiments of the present disclosure, the "feeding terminal 300 or the first capacitor 500 is disposed in the slot 210", and a person skilled in the art can understand how to implement the feeding terminal 300 or the first capacitor 500 according to the related art. For example: the first capacitor 500 and the feed terminal 300 are connected across the width of the slot. As shown in fig. 8, the positive (+) stage of the feeding terminal 300 and the first capacitor 500 is connected to the upper portion of the slot, and the negative (-) stage of the feeding terminal 300 and the first capacitor 500 is connected to the lower portion of the slot. In actual operation, the lower portion of the slot and the PCB board of the system are electrically connected to each other by screws on the PCB board and a metal housing. The feeding terminal 500 of the slot may be implemented by a 50 ohm transmission line or a spring plate. When the slot antenna is fed using a 50 ohm transmission line, the core (i.e., the positive pole) of the transmission line is connected to the upper portion of the slot, and the outer conductor (i.e., the negative pole) of the transmission line may be directly connected to the ground of the PCB board. When the slot antenna is fed using the dome, the core of the dome is connected to the upper portion of the slot, and the ground of the dome can be directly soldered to the ground of the PCB. Similarly, the first capacitor 500 may also be configured to draw the upper portion of the slot (i.e., the positive electrode of the capacitor) out through the elastic piece and connect to an independent pad of the PCB, solder the positive electrode of the capacitor to the independent pad, and connect the other end (or the negative electrode) of the capacitor to the ground of the PCB. Other ways of applying capacitance and feeding power on two sides of the slot are within the protection scope of the patent, and are not described herein again as long as they are applied on two sides of the slot.

The generation of the slot antenna resonance is similar to the resonant circuit in nature, and the capacitance is bridged in the slot antenna, which is equivalent to increasing the capacitance value of the resonant circuit, thereby correspondingly reducing the resonant frequency of the slot antenna. The reduction in resonant frequency, i.e., equivalently the increase in the effective electrical length of the slot antenna, i.e., the slot length of the antenna structure of the present disclosure may be smaller at the same resonant frequency.

Meanwhile, according to the working principle of the capacitor, the larger the voltage difference applied to the two poles of the capacitor is, the stronger the effect generated by the capacitor is. From this, it can be seen that the position of the first capacitor 500 should satisfy: the stronger the voltage value at the position of the first capacitor 500, the greater the degree of the antenna shift to low frequencies, i.e. the higher the effective electrical length of the antenna.

Therefore, as for the 1/4 wavelength slot antenna in the present embodiment, it can be seen from analyzing the voltage distribution of the resonance, that the voltage gradually decreases in the direction from the first end 121 to the second end 122, that is, the voltage value at the opening 220 is the largest, and the voltage value at the ground end is zero. Therefore, in the present embodiment, the first capacitor 500 is disposed at one end close to the opening 220, i.e., one end close to the first end 121 in the drawing, in the first direction. Therefore, the stronger the capacitance effect is, the effective electrical length of the antenna is improved to the greatest extent, namely, the opening length of the gap can be reduced under the same resonant frequency.

On the basis, different capacitance values can also influence the performance of the antenna, and the principle of the capacitance can be known to satisfy the following conditions: the larger the capacitance value of the applied first capacitor, the stronger the effect of shifting the antenna resonance frequency towards low frequencies, i.e. the longer the effective electrical length of the antenna. It should be noted, however, that the magnitude of the applied capacitance is inversely proportional to the efficiency of the antenna, so that as small a capacitance as possible should be used to ensure antenna performance. However, the resonant frequency of the antenna can be finely adjusted by changing the capacitance, which can be understood by those skilled in the art and will not be described in detail.

The idea of the present embodiment is that: by adding the capacitor in the slot antenna, the effective electrical length of the antenna slot can be increased and the working frequency of the antenna can be reduced under the same slot length; that is, the antenna structure of the present disclosure may reduce the length of the slot while achieving the same operating frequency. Therefore, the structure of the slot antenna is not limited to the structure shown in fig. 8, and the application of capacitance can achieve corresponding effects on the basis of any of the foregoing embodiments, which is not enumerated in the present disclosure.

In a second aspect, the embodiments of the present disclosure provide a wearable device, which includes the antenna structure in any of the above embodiments. The wearable device of the present disclosure may be any device type suitable for implementation, such as a wrist-worn device like a smart watch or a smart bracelet; also, head-mounted devices such as smart headsets, smart glasses, and the like; wearable devices such as smart apparel; etc., to which the present disclosure is not limited.

In an exemplary embodiment, the wearable device takes a smart watch as an example, the smart watch is a watch with a metal shell, and the structure of the shell is shown in the embodiment of fig. 1a and 1b, which is not described again. Inside the housing a main board (not shown in the drawings) is arranged, which main board comprises a feeding circuit, to which feeding terminals of the antenna structure are connected. The smart watch comprises a Bluetooth antenna and a satellite positioning antenna, wherein the satellite positioning antenna is a GPS satellite positioning antenna, a Beidou satellite positioning antenna and the like. It will be understood by those skilled in the art that the detailed description is not repeated.

As shown in fig. 1a, the bluetooth antenna 201 and the satellite positioning antenna 202 are symmetrically disposed on the frames 120 on two opposite sides of the housing, and in this embodiment, the bluetooth antenna 201 and the satellite positioning antenna 202 have completely symmetrical structures in the above embodiments, that is, the bluetooth antenna 201 utilizes the ground terminal 400 to realize that the first slot of the bluetooth antenna 201 and the second slot of the satellite positioning antenna 202 have the same length. It can be seen that, from the appearance of the casing, no matter two antennas on two opposite sides or each antenna is a symmetrical structure, the appearance integrity of the device is better. In addition, in the embodiment, the shell does not need to be provided with an annular gap, so that the gap length of the frame is greatly reduced, the watch is strong and higher in structure, and the waterproof grade is higher.

It is understood that the above examples are only used for illustrating the present disclosure, and do not limit the present disclosure, and in other embodiments, the number of antennas of the watch may also be any other number suitable for implementation, for example, only a satellite positioning antenna is provided on the device housing, a bluetooth antenna is provided inside, and for example, the device may further include a WIFI antenna, an LTE antenna, a 5G antenna, and the like, where the volume allows, in addition to the satellite positioning and bluetooth antennas. The wearable device may also be other types of devices, such as a headset, a bracelet, and the like. The shape of the housing is not limited to the rectangular structure, and may be any other shape suitable for implementation, such as a circle, and the like, which is not described in detail in this disclosure.

In the example shown in fig. 1b, the slot width W of the two antennas is 1.2mm as a typical dimension, and the ratio of the length of the feeding terminal 300 from the ground terminal is 0.1-0.2. Fig. 6 shows a return loss and an isolation curve between antennas of the satellite positioning antenna and the bluetooth antenna of the watch in the present embodiment. As can be seen from the results of fig. 6, in the present embodiment, the satellite positioning antenna and the bluetooth antenna not only have good return loss, but also have high isolation between the two antennas.

Fig. 7 shows the radiation efficiency and total efficiency curves of the satellite positioning antenna and the bluetooth antenna of the watch in this embodiment. It can be seen that the antenna structure in this embodiment has high radiation efficiency and overall efficiency, and has good antenna performance.

Can know through the aforesaid, this disclosed embodiment provides wearable equipment, adopts all metal casing, and structural strength and outward appearance feel are better to the antenna gap is littleer, and the wholeness and the outward appearance of equipment are better, have good impression, improve user experience.

It should be understood that the above embodiments are only examples for clearly illustrating the present invention, and are not intended to limit the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. For example, the opening position of the slot antenna may be on the bottom housing or other positions instead of above the metal middle frame, as long as the end of the slot far from the feeding end is provided with an opening to form a (1/4) wavelength slot, and this need not be exhaustive. And obvious variations or modifications of the present disclosure may be made without departing from the scope of the present disclosure.

Claims

1. An antenna structure, applied to a wearable device, wherein the wearable device includes a metal casing, the casing includes a bottom casing and a frame surrounding a periphery of the bottom casing and integrally connected with the bottom casing, the antenna structure includes:

2. The antenna structure according to claim 1,

the second end of the slot forms the ground terminal.

3. The antenna structure according to claim 1, further comprising:

4. The antenna structure according to claim 1,

and a groove is formed in the outer side wall of the second end of the gap, and the groove is symmetrical to the opening in shape in the first direction.

5. The antenna structure according to claim 1 or 4,

and the gap is filled with an injection molding structure matched with the shape, and the injection molding structure is made of a non-metal material.

6. The antenna structure according to claim 1, further comprising:

7. The antenna structure according to claim 1,

in the first direction, the distance between the feed terminal and the grounding terminal is a first length, the distance between the first end and the grounding terminal is a second length, and the ratio of the first length to the second length is 0.1-0.2.

8. A wearable device characterized by comprising an antenna structure according to any of claims 1 to 7.

9. The wearable device of claim 8,

the Bluetooth antenna and the satellite positioning antenna are of the antenna structures and are respectively arranged on two opposite sides of the frame;

10. The wearable device of claim 8, wherein the wearable device is a smart watch or a smart bracelet.