WO2020156063A1

WO2020156063A1 - Antenna structure, multiple-input multiple-output (mimo) antenna, and terminal

Info

Publication number: WO2020156063A1
Application number: PCT/CN2020/070815
Authority: WO
Inventors: 刘洋
Original assignee: 中兴通讯股份有限公司
Priority date: 2019-01-30
Filing date: 2020-01-08
Publication date: 2020-08-06
Also published as: CN111509364A

Abstract

Disclosed are an antenna structure, a multiple-input multiple-output (MIMO) antenna, and a terminal. The antenna structure comprises a main board; and a bracket antenna arranged in a clearance area of the main board, wherein the bracket antenna comprises a first resonator connected to a feed end, and at least one nested resonator spaced apart from the first resonator; a spacing between the first resonator and the main board is not equal to a spacing between the at least one nested resonator and the main board; and the first resonator and the at least one nested resonator at least partially overlap in a direction perpendicular to the main board.

Description

Antenna structure, multiple input multiple output MIMO antenna and terminal

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office with an application number of 201910091038.7 on January 30, 2019. The entire content of this application is incorporated into this application by reference.

Technical field

The present application relates to the field of antenna technology, such as an antenna structure, a Multiple-Input Multiple-Output (MIMO) antenna and a terminal.

Background technique

With the development of wireless communication technology and the increasing rise of multiple communication standards, the functions of wireless terminal products will also become more and more complex, and generally can support multiple frequency bands and different communication standards. The internal circuits of wireless products are also more complicated, and the space reserved for antennas in the design of wireless terminal products is becoming less and less, but the functional requirements for antennas are increasing. There are many types of wireless products on the market, and users can have more choices when buying products. Most users tend to buy wireless products that are small in size and easy to carry. Therefore, whether it is technological development or market trends, the requirements for miniaturization of wireless smart products are getting higher and higher. The high integration of circuits can keep up with the demand for miniaturization of wireless devices, but the size of the antenna often becomes a "bottleneck" for reducing the size of wireless products. Therefore, miniaturization, multiple frequency bands, and wide frequency bands are an important development trend in antenna design.

Antenna, as an important part of wireless terminal products, not only directly affects the transceiver performance of wireless terminal equipment, but also affects the overall size and aesthetics of the wireless terminal. Therefore, a design that can meet structural requirements, customer requirements, and antenna performance indicators The required antenna has become a problem currently facing the industry.

In related technologies, wireless terminal products contain multiple antennas, and multiple antennas are used at the transmitting end and the receiving end to receive and transmit at the same time. Therefore, the terminal antenna system will inevitably cause the mutual coupling between multiple antennas, resulting in antennas. The correlation between them is reduced, thereby reducing the communication capacity, but also reducing the radiation efficiency of the antenna. Generally, in order to reduce the coupling between antennas, it is required to increase the distance between the antennas. Often the limited space of smart wireless terminal products cannot meet this requirement, especially in the low frequency band around 700MHz. The distance is usually only one tenth of the wavelength, which intensifies the degree of coupling.

Wireless terminal products have strict requirements on the size of the whole machine. How to realize the multi-antenna technology in a small space is a technical difficulty.

Summary of the invention

The embodiments of the present application provide an antenna structure, a MIMO antenna, and a terminal, which can improve the low-frequency performance of the antenna without being limited by the physical size of the terminal, and is especially suitable for terminals with a smaller physical size.

The embodiment of the present application provides an antenna structure, including: a main board; a support antenna arranged in a clear area of the main board, the support antenna includes a first resonator connected to a feeding end, and a At least one nested resonator in which the resonant components are spaced apart from each other, the interval between the first resonator and the main board is not equal to the interval between the at least one nested resonator and the main board, the The first resonator and the at least one nested resonator at least partially overlap in a direction perpendicular to the main board.

The embodiment of the present application also provides a multiple-input multiple-output MIMO antenna, including the antenna structure described in the embodiment of the present application; wherein the bracket antenna of the antenna structure is arranged at least one of the following positions on the main board of the antenna structure : Top position; side position.

The embodiment of the present application also provides a terminal, including the antenna structure described in the embodiment of the present application, and further including a processor and a memory.

Description of the drawings

FIG. 1 is a schematic diagram of an antenna structure in an embodiment of the application;

2 is a partial schematic diagram of an antenna structure in another embodiment of the application;

FIG. 3 is a partial schematic diagram of an antenna structure in another embodiment of this application;

FIG. 4 is a schematic diagram of the comparison between the antenna structure provided by the embodiment of the present application and the antenna structure in the related art before and after the input return loss is increased.

detailed description

The technical solution of the present application will be further elaborated below in conjunction with the drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of this application. The terms used in the specification of the application herein are only for the purpose of describing specific embodiments, and are not intended to limit the application. The term "and/or" as used herein includes any and all combinations of one or more related listed items.

In the description of this application, the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", " The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, rather than indicating or implying the device or The element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the application. In the description of this application, unless otherwise specified, "plurality" means two or more.

In the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral Connection; It can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meaning of the above terms in this application can be understood according to actual application conditions.

Before describing the embodiments of the present application in further detail, the terms and terms involved in the embodiments of the present application will be described. The terms and terms involved in the embodiments of the present application are applicable to the following interpretations.

1) Input return loss (S11) refers to the performance parameter of a part of the incident power being reflected back to the signal source.

2) Isolation (S12) refers to the ratio of the signal transmitted by one antenna to the signal received by another antenna and the signal of the transmitting antenna.

3) Scattering parameters, S-parameters are scattering parameters, which are used to evaluate the performance of the signal emitted and transmitted by the object under test. Among them, the S parameters include input return loss S11 and isolation S12.

4) Specific Absorption Ratio (SAR) refers to the electromagnetic radiation energy absorbed by a unit mass of matter per unit time.

5) Correlation refers to the correlation between the main antenna and the diversity antenna, such as the gain difference within the set range.

6) Multiple input and multiple output (MIMO) refers to the use of multiple transmitting antennas and receiving antennas at the transmitting end and receiving end respectively, so that signals are transmitted and received through multiple antennas at the transmitting end and the receiving end.

7) Band refers to the frequency range of electromagnetic waves, and the unit is Hz.

8) Long Term Evolution (LTE) is the long-term evolution of the Universal Mobile Telecommunications System (UMTS) technical standards formulated by the Third Generation Partnership Project (3GPP) organization.

Among related technologies, the research on multi-frequency and small mobile terminal antennas has achieved remarkable results. In a general design, the size of the base plate required for the mobile phone terminal antenna is relatively large, and the surface current distributed on the base plate is also very strong, resulting in a large overall antenna size and unstable antenna performance, which is not conducive to the miniaturization of the mobile phone terminal. The design of a multi-frequency mobile phone terminal antenna with compact structure, stable performance, and similar forward radiation characteristics with a symmetrical array at high frequencies is still difficult to design. Moreover, the known unified Extensible Firmware Interface (UEFI) type terminal products usually require an increase in the size of the whole machine in order to improve the low-frequency (mainly below 960MHz) performance of the antenna, and the UEFI type terminal The limited size and space of the product cannot meet this requirement, especially in the 700MHz frequency band, which makes it difficult to achieve low frequency (698MHz-960MHz), and the electrical distance between several antennas is usually only one tenth of the wavelength. The degree of coupling is further intensified, and the efficiency of the antenna cannot meet the normal requirements. At present, the overall size of UEFI products is still not greatly reduced. The commonly used method to reduce antenna correlation is to sacrifice antenna clearance and layout. The disadvantage of this method is that the limited size of the terminal makes it difficult to achieve low frequency (698MHz-960MHz), and it is not conducive to the miniaturization of terminal products. , Even in order to increase the performance of the antenna had to increase the overall size.

In order to solve the above-mentioned problems, as shown in FIG. 1, an embodiment of the present application provides an antenna structure 30. The antenna structure 30 can be applied to a variety of wireless smart terminal devices, especially for small physical size wireless smart terminals. Equipment, such as miniaturized trackers, smart watches, smart bracelets, mobile terminals, etc. The antenna structure 30 includes a main board 10; a support antenna 20 arranged in the clearance area 12 of the main board 10, and the support antenna 20 includes a first resonator 21 connected to a feeding end, and a first resonator connected to the first resonator. 21 at least one nested resonator 28 spaced apart from each other, and the interval between the first resonator 21 and the main board 10 is not equal to the interval between the at least one nested resonator and the main board, The first resonator 21 and the at least one nested resonator 28 at least partially overlap in a direction perpendicular to the main board 10.

Here, the number of at least one nested resonator 28 means that the number of nested resonator 28 may be one or more. In the foregoing embodiment of the present application, the spacing between the first resonator 21 and the nested resonator 28 relative to the main board 10 is not equal, and the first resonator 21 and the nested resonator 28 are in a direction perpendicular to the main board 10 At least partially overlapped, so that the first resonator 21 and the nested resonator 28 form a coupling and jointly form a resonant structure to reduce the operating frequency of the antenna; the coupling resonance between the first resonator 21 and the nested resonator 28 It is superimposed with the self-resonance of the original antenna trace 22 of the antenna structure 30, thereby effectively improving the low frequency performance of the antenna.

The main board 10 may be a printed circuit board (Printed Circuit Board, PCB) main board. The material and shape of the first resonator 21 and the nested resonator 28 may be the same. Optionally, both the first resonator 21 and the nested resonator 28 are in the shape of a metal sheet, such as a rectangular metal copper sheet. The at least partial overlap of the first resonator 21 and the nested resonator 28 in a direction perpendicular to the main board 10 may refer to any one of the following: the first resonator 21 and the nested resonator 28 has the same shape and size, and is arranged in a direction perpendicular to the main board 10, so that the first resonator 21 and the nested resonator 28 completely overlap; or, the first resonator 21 and the nested resonator The resonator 28 has the same shape and size, and is staggered in the direction perpendicular to the main board 10, so that the first resonator 21 and the nested resonator 28 partially overlap; or, the first resonator 21 and The nested resonator 28 has different shapes and/or sizes, and is staggered in a direction perpendicular to the main board 10, so that the first resonator 21 and the nested resonator 28 partially overlap. In an embodiment, the materials and shapes of the first resonator 21 and the nested resonator 28 may also be different. For example, the first resonator 21 may be a rectangular sheet-shaped copper sheet, and the nested resonator 28 may be of other shapes or materials. The size of the nested resonator 28 may be smaller than the first resonator 21, as long as the first resonator 21 and the nested resonator 28 at least partially overlap in the direction perpendicular to the main board 10 The other setting methods are all possible, and the embodiment of the present application does not limit it here.

Clearance refers to the open area in the vertical projection area of the antenna (the upper and lower ranges must be considered). Within the projection area of the antenna trace 22, the main board 10 should not be laid on the ground (especially the onboard antenna), and the clearance of the antenna should be maintained to improve the radiation efficiency of the antenna. The bracket antenna 20 refers to an antenna form in which a bracket is set and antenna wiring is performed on the bracket. The specific routing of the antenna can be flexibly designed according to the form of the bracket in the actual product when the antenna is wired on the bracket, and there is no limitation here. Optionally, the antenna wiring can connect the first resonator 21 to the feed point of the main board 10 through the feed line 27.

Wherein, the size of the clearance area 12, the first resonator 21, and the second resonator 23 (or called coupling resonator) can be adjusted according to the size of the main board 10 in actual applications. Taking the terminal as a wireless tracker as an example, the whole size of the wireless tracker is 45*45mm, the size of the main board 10 is 40*40mm, and the size of the clearance area 12 of the main board 10 is 8*40mm. The working frequency band realized by the antenna structure includes LTE B12 (698-750MHz), LTE B2 (1850-2170MHz), and LTE B4 (1710-2155MHz). The size of the first resonator 21 is 4*6mm. The sleeve resonator 28 is nested inside the first resonator 21 and has the same shape and size as the first resonator 21. Here, the antenna headroom area only needs to meet the requirements of the radiating antenna, and no new antenna headroom is required. The size and position of the bracket are reasonably set according to the size of the antenna headroom area 12, and both the first resonator 21 and the nested resonator 28 are provided In the area covered by the bracket, there is no need to increase the original physical size of the terminal.

In some embodiments, the bracket antenna 20 includes a first bracket 25 arranged in the clearance area 12 of the main board 10 and a second bracket 26 arranged in the first bracket 25, and the first bracket 25 is opposite to The first interval between the main boards 10 is greater than the second interval between the second bracket 26 and the main board 10, the first resonator 21 is disposed on the first bracket 25, and the nesting The resonator 28 includes a second resonator 23 arranged on the second bracket 26. Here, the nested resonator 28 includes the second resonator 23 nested in the first resonator 21. In order to facilitate the arrangement of the first resonator 21 and the second resonator 23, the first bracket 25 and the second bracket 26 are nested, that is, the second bracket 26 with a different height relative to the main board 10 is used to be arranged in the first bracket. In the bracket 25, the first resonator 21 and the second resonator 23 are respectively arranged on the first bracket 25 and the second bracket 26, so as to realize the nesting of the second resonator 23 in the first resonator 21 internal. Optionally, both the first bracket 25 and the second bracket 26 are made of plastic materials, and the first bracket 25 includes a carrying portion spaced a first distance from the main board 10 and two ends connected to the carrying portion. The connecting portion between the motherboards 10. The shape of the second bracket 26 may be the same as the shape of the first bracket 25, and the distance between the bearing portion of the second bracket 26 and the main board 10 is smaller than that of the bearing portion of the first bracket 25. The interval between the main boards 10 is described.

In some embodiments, still taking the terminal as the above-mentioned wireless tracker as an example, the first distance between the first bracket 25 and the main board 10 may be 5 mm, and the second bracket 26 is relative to the main board 10 The second interval may be 2mm. The arrangement at such intervals can make the coupling between the first resonator 21 and the second resonator 23 respectively arranged on the first support 25 and the second support 26 better, so that the first resonator The coupling resonance between 21 and the second resonator 23 can be superimposed with the self-resonance of the antenna trace 22 to deepen the resonance of the low-frequency LTE B12 (698-750MHz) frequency band of the antenna.

In the implementation of this application, the number of the nested resonator 28 may be one or more, that is, the nested resonator 28 is not limited to include the second resonator 23, and may include more to form Multi-level nesting, for example, it can be 2 or more. If the nested resonator 28 includes two layers as an example, please refer to FIGS. 1 and 2. The bracket antenna 20 further includes a third bracket disposed in the second bracket 26, and the third bracket is relative to the The third interval between the main boards 10 is smaller than the second interval, and the nested resonator 28 further includes a third resonator 24 arranged on the third bracket. In one embodiment, the nested resonator 28 further includes a third resonator 24 nested in the second resonator 23, wherein, in order to facilitate the arrangement of the third resonator 24, a bracket nesting method can be used to realize the nesting. The nesting of the resonator 28 is nested by the third bracket and the second bracket 26, and the third bracket with a different height relative to the main board 10 is arranged inside the second bracket 26, and by The third resonator 24 is arranged on the third bracket, so that the third resonator 24 is nested inside the second resonator 23, so that the first resonator 21, the second resonator 23, and the third resonator are integrally formed. A two-layer resonant nesting structure in which the components 24 are nested sequentially. Optionally, the shape and material of the third bracket may be the same as those of the first bracket 25 and the second bracket 26, and make the third interval of the third bracket relative to the main board 10 smaller than that of the second bracket 26 relative to the The second interval of the main board 10.

In some embodiments, referring to FIG. 3, the nested resonator 28 is provided with an opening, and the position of the opening is opposite to the position of the first resonator 21 in a direction perpendicular to the main board 10; And/or, the first resonator 21 is provided with an opening, and the position of the opening is directly opposite to the position of the nested resonator 28 in a direction perpendicular to the main board 10. Wherein, the opening correspondingly penetrates through two opposite surfaces of the corresponding resonator, and the shape, position and size of the opening can be adjusted according to the actual working frequency band of the antenna structure 30. To facilitate the distinction, the opening provided on the nested resonator 28 is referred to as the second opening 230, and the opening provided on the first resonator 21 is referred to as the first opening 210.

In one embodiment, the solution for arranging openings on the corresponding resonator may be: please refer to FIG. 1 again, only the second opening 230 is provided on the nested resonator 28; or, the second opening 230 is provided only on the first resonator 21 An opening 210; or, as shown in FIG. 3, a first opening 210 and a second opening 230 are respectively provided on the first resonator 21 and the nested resonator 28. Still taking the terminal as the above wireless tracker as an example, the nested resonator 28 includes a second resonator 23 nested in the first resonator 21, and the first resonator 21 and the second resonator 23 are respectively rectangular Sheet metal. The first opening 210 is provided in the middle of the first resonator 21, and the first resonator 21 provided with the first opening 210 has a symmetrical shape; the second opening 230 is provided in the middle of the second resonator 23 and is provided with the The second resonator 23 of the second opening 230 also has a symmetrical shape. The location of the first opening 210 is directly opposite to the location of the nested resonator 28 in the direction perpendicular to the main board 10, that is, the projection of the area where the first opening 210 is formed on the main board 10 is located on the first The second resonance component 23 is within the projection range of the main board 10. The position of the second opening 230 is directly opposite to the position of the first resonator 21 in the direction perpendicular to the main board 10, that is, the projection of the area where the second opening 230 is formed on the main board 10 is located on the first A resonator 21 is within the projection range on the main board 10.

In some embodiments, the extending direction of the opening is consistent with the length direction of the main board 10. In an embodiment, the opening may be a long rectangle, and the extension direction of the opening, that is, the length direction of the opening, is consistent with the length direction of the main board 10. Wherein, increasing the length of the opening can increase the coupling performance between the first resonator 21 and the nested resonator 28. In an embodiment, one end of the opening along its extension direction corresponds to the first resonator 21 Or the sides of the nested resonator 28 are flush, that is, the opening extends to the end of which penetrates the corresponding side of the nested resonator 28 or the corresponding first resonator 21. Wherein, when the opening is provided on the nested resonator 28, one end of the opening along its extension direction is flush with the side of the corresponding nested resonator, and the first resonator 21 is provided When there is the opening, one end of the opening along its extension direction is flush with the side of the corresponding first resonator 21. In one embodiment, the first opening 210 extends along the length direction of the main board 10 and extends to one of the ends of the first resonator 21 that is parallel to the width direction of the main board 10; The length direction extends and extends to the side of the second resonator 23 parallel to the width direction of the main board 10 at its end, so that when the opening is disposed on the corresponding resonator, the length of the opening can be as matched as possible The size of the resonant element should be increased as much as possible when required to increase the coupling performance between the first resonator element 21 and the nested resonator element 28.

In some embodiments, the support antenna 20 further includes a short-circuit stub 29, and the short-circuit stub 29 connects the nested resonator 28 with the feed end of the main board 10. The nested resonator 28 and the first resonator 21 are arranged in a nested manner, and the nested resonator 28 is connected to the ground of the main board 10 through the short-circuit branch 29, so that the antenna structure 30 uses the same dielectric layer and the same reference ground as a whole , Wherein the first resonator 21 and the nested resonator 28 form a coupling and jointly form a resonant structure, and the coupling resonance between the first resonator 21 and the nested resonator 28 is the same as the self-resonance of the original antenna trace 22 The superposition can effectively improve the low-frequency performance of the antenna, which not only solves the isolation and correlation between multiple antennas, but also solves the problem that low frequencies are difficult to achieve in a small space, and reduces the SAR value of the antenna.

In the above-mentioned embodiment of the present application, the antenna structure 30 forms a coupling resonant structure through the first resonator 21 and the nested resonator 28, and the coupling resonance between the first resonator 21 and the nested resonator 28 is similar to the original antenna. The self-resonance of the line 22 is superimposed, and the two parts of the resonant performance are superimposed in the specific frequency band of the antenna, which can improve the low-frequency performance of the antenna. Please refer to FIG. 4, which is the antenna structure 30 in the related art (that is, the first resonance is not used). Comparison of the input return loss parameter (S11[old]) of the antenna structure 30) of the component 21 and the nested resonator component 28 and the input return loss parameter (S11[new]) of the antenna structure 30 provided by the embodiment of the present application As can be seen from FIG. 4, the input return loss parameter of the antenna structure 30 provided by the embodiment of the present application is deepened at the lowest point of antenna resonance, and the resonance of the entire low frequency band is enhanced.

Please refer to the following Table 1, which is a comparison of the test results of the low frequency efficiency of the known antenna structure 30 and the antenna structure 30 provided by the embodiment of the present application:

Table I

It can be seen from the above table 1 that the low frequency of the antenna structure 30 provided by the embodiment of the application, especially around 700MHz, can reach about 21% to 26%, which is only 9% to 12% compared to the known antenna structure 30. % Has been significantly improved, and the low-frequency performance of the antenna is better improved without increasing the physical size of the terminal.

On the other hand, the embodiments of the present application also provide a multiple-input multiple-output (MIMO) antenna. The MIMO antenna includes the antenna structure 30 provided by any one of the embodiments of the present application (as shown in FIGS. 1 to 3). The number of the antenna structure 30 may be multiple, the support antenna 20 of the antenna structure 30 may be arranged at the top position and/or side position of the main board 10, the size of the first resonator 21 and the nested resonator 28 It can be adjusted according to actual needs or the layout position of the antenna structure 30.

In another aspect of the embodiments of the present application, a terminal is also provided. The terminal includes the antenna structure 30 provided in any of the embodiments of the present application (as shown in FIGS. 1 to 3). The terminal may be a small-sized wireless smart terminal device, such as a miniaturized tracker, smart watch, smart bracelet, mobile phone terminal, etc. As those of ordinary skill in the art know, the terminal may also include a processor and a memory.

Claims

An antenna structure, including:

Motherboard

A cradle antenna arranged in the clear area of the main board, the cradle antenna includes a first resonator connected to the feed end, and at least one nested resonator spaced apart from the first resonator, the first The interval between a resonator element relative to the main board and the interval between the at least one nested resonator element and the main board are not equal, and the first resonator element and the at least one nested resonator element are located along the At least partially overlap in the direction perpendicular to the main board.
5. The antenna structure of claim 1, wherein the support antenna further comprises a first support provided in the clear area of the main board and a second support provided in the first support, the first support The first interval between the opposite to the main board is greater than the second interval between the second bracket and the main board, the first resonator is disposed on the first bracket, and the at least one nested resonator It includes a second resonator arranged on the second bracket.
5. The antenna structure of claim 2, wherein the support antenna further comprises a third support provided in the second support, and a third distance between the third support and the main board is smaller than that of the In the second interval, the at least one nested resonator further includes a third resonator arranged on the third bracket.
The antenna structure according to claim 1, further comprising at least one of the following:

The at least one nested resonator is provided with an opening, and the position of the opening is opposite to the position of the first resonator in a direction perpendicular to the main board;

The first resonator is provided with an opening, and the position of the opening is opposite to the position of the at least one nested resonator in a direction perpendicular to the main board.
5. The antenna structure of claim 4, wherein the extending direction of the opening is consistent with the length direction of the main board.
The antenna structure according to claim 5, wherein, when the opening is provided on the at least one nested resonator, one end of the opening along its extension direction resonates with the corresponding at least one nested resonator The sides of the piece are flush;

In the case where the opening is provided on the first resonator, one end of the opening along its extension direction is flush with the side of the corresponding first resonator.
5. The antenna structure of claim 1, wherein the first resonator and the at least one nested resonator are both in the shape of a metal sheet.
7. The antenna structure according to any one of claims 1 to 7, wherein the support antenna further comprises a short-circuit stub, and the short-circuit stub is configured to connect the nested resonator to the feed end of the main board.
A multiple-input multiple-output MIMO antenna, comprising the antenna structure according to any one of claims 1 to 8, wherein the support antenna of the antenna structure is arranged at at least one of the following positions on the main board of the antenna structure: Top position; side position.
A terminal, comprising the antenna structure according to any one of claims 1 to 8, and further comprising a processor and a memory.