WO2018119946A1

WO2018119946A1 - Multi-input multi-output antenna system and mobile terminal

Info

Publication number: WO2018119946A1
Application number: PCT/CN2016/113251
Authority: WO
Inventors: 李慧; 朱佳佳; 孙思宁
Original assignee: 深圳天珑无线科技有限公司
Priority date: 2016-12-29
Filing date: 2016-12-29
Publication date: 2018-07-05

Abstract

The application relates to the field of antennas, and specifically, to a multi-input multi-output (MIMO) antenna system and a mobile terminal. The antenna system comprises: a substrate having a length direction and a width direction; and a first metal piece and a second metal piece arranged opposite to each other and along the width direction of the substrate. The first metal piece, the second metal piece, and the substrate are radiators in the MIMO antenna systems. Gaps are provided between the substrate and the first metal piece and the second metal piece, respectively. The first metal piece comprises thereon a first feed point. A first matching circuit is configured between the first feed point and the substrate. The first feed point and the substrate are electrically connected to two sides of the first matching circuit. The second metal piece comprises thereon a second feed point. A second matching circuit is configured between the second feed point and a second substrate. The second feed point and the substrate are electrically connected to two sides of the second matching circuit. The MIMO system in the embodiment has favorable orthogonality, a low correlation coefficient, and high a communication rate of a communication system.

Description

Multiple input multiple output antenna system and mobile terminal

Technical field

The present application relates to the field of antenna technologies, and in particular, to a multiple input multiple output antenna system and a mobile terminal.

Background technique

With the large-scale application of 4G technology, communication systems are increasingly demanding communication reliability and transmission rate. At present, mobile terminals such as mobile phones analyze and design the antenna independently from the substrate. The resonant frequency is often determined by changing the size of the antenna itself. However, this ignores the radiation characteristics of the substrate itself. For communication bands with a frequency less than 1 GHz, the main The radiation mode relies on the radiation in the length direction of the substrate, but the multi-antenna system generated by this mode only has strong coupling and high correlation coefficient, which seriously affects the channel capacity and diversity gain of the communication system.

Summary of the invention

The present application provides a multiple input multiple output antenna system and a mobile terminal, which can solve the above

technical problem

A first aspect of the present application provides a multiple input multiple output antenna system including a substrate having a length direction and a width direction, and first and second metal members disposed opposite to each other in a width direction of the substrate The first metal member, the second metal member, and the substrate are all radiators of the multiple input multiple output antenna system, and the first metal member and the second metal member are both opposite to the substrate With gaps,

a first feeding point is disposed on the first metal member, and a first matching circuit is disposed between the first feeding point and the substrate, and two sides of the first matching circuit are respectively associated with the first feeding The electrical point is electrically connected to the substrate,

a second feeding point is disposed on the second metal member, and a second matching circuit is disposed between the second feeding point and the second substrate, and two sides of the second matching circuit are respectively associated with the first Two feed The point is electrically connected to the substrate.

Preferably,

The longitudinal cross-sectional area of the first metal member and/or the longitudinal cross-sectional area of the second metal member gradually decreases in a direction perpendicular to the substrate, the longitudinal cross-section being a cross section parallel to the substrate.

Preferably,

The opposite sides of the first metal member along the length direction of the substrate are asymmetrically disposed with respect to a center plane of the first metal member, and/or

The two opposite sides of the second metal member along the length direction of the substrate are asymmetrically disposed with respect to a central surface of the first metal member;

The central surface is a surface that is perpendicular to the substrate while extending along the width direction of the substrate.

Preferably,

The first feed point is offset from a center of the first metal piece, the center being a midpoint of a line between two points of the first metal piece farthest along the length direction, and /or

The second feed point is offset from a center of the second metal piece, the center being a midpoint of a line between two points of the second metal piece that are furthest along the length direction.

Preferably, the first feed point and the second feed point are disposed opposite each other along the width direction.

Preferably, the substrate has a first groove coupled to the first metal member and/or a second groove coupled to the second metal member along a length thereof.

Preferably,

The first metal member is divided into a first segment and a second segment by the first feeding point, and along the length direction, a length of the first segment is greater than a length of the second segment, the first a segment coupled to the first groove; and/or

The second metal piece is divided into a third segment and a fourth segment by the second feeding point, along the length direction, the length of the third segment is greater than the length of the fourth segment, the third A segment is coupled to the second groove.

Preferably, at least one of the first matching circuit and the second matching circuit is an L-type matching circuit.

Preferably, the method further includes a first insulating support plate printed with the first metal member and printed A second insulating support plate of the second metal member, wherein the first insulating support plate and the second insulating support plate are both connected to the substrate.

A second aspect of the present application provides a mobile terminal comprising the multiple input multiple output antenna system and the housing of any of the above, the multiple input multiple output antenna system being disposed within the housing.

The technical solution provided by the present application can achieve the following beneficial effects:

The multi-input multi-output antenna system provided by the present application realizes the loading of the capacitor by providing the opposing first metal member and the second metal member in the width direction of the substrate, thereby effectively reducing the radiation pattern of the substrate along the width direction. The radiation frequency is similar to the radiation frequency of the substrate along the length direction, and the radiation pattern of the substrate along the width direction is orthogonal to the radiation pattern of the substrate along the length direction, and further, the first feed point and the second feed point are respectively excited The diagonal pattern of the radiation pattern of the substrate along the width direction and the radiation pattern of the substrate along the length direction are used, and the two diagonal modes are also approximately orthogonal, thereby fully utilizing the radiation pattern of the substrate itself. And the designed multi-input multi-output antenna system has good orthogonality, low correlation coefficient, small mutual coupling and high efficiency, so the data transmission rate of the communication system can be greatly improved. In addition, the multi-input multi-output antenna system has strong electromagnetic compatibility, so that the surrounding environment, including hands, heads, etc., generates less interference near the antenna.

The above general description and the following detailed description are merely exemplary and are not intended to limit the application.

DRAWINGS

1 is a schematic perspective structural view of a multiple input multiple output antenna system according to an embodiment of the present application;

2 is a schematic diagram of a matching circuit of a multiple input multiple output antenna system according to an embodiment of the present application;

3 is a size indication diagram of a multiple input multiple output antenna system according to an embodiment of the present application;

4 is a relationship diagram of simulated S parameters and frequencies of a multiple input multiple output antenna system according to an embodiment of the present application;

FIG. 5a and FIG. 5b are schematic diagrams of simulated radiation of a multiple input multiple output antenna system according to an embodiment of the present application.

Reference mark:

10-substrate;

11-first metal piece;

110-first feed point;

111-first paragraph;

112-second paragraph;

12-second metal piece;

120-second feed point;

121-third paragraph;

122-fourth paragraph;

13-first matching circuit;

14-second matching circuit;

15-first groove;

16-second groove;

17-first insulating support plate;

18-second insulating support plate;

19-first interface;

20-second interface.

The drawings herein are incorporated in and constitute a part of the specification,

detailed description

The present application will be further described in detail below through specific embodiments and with reference to the accompanying drawings.

As shown in FIG. 1 , the embodiment of the present application provides a multi-input multi-output antenna system, which can be applied to mobile terminals such as mobile phones. The multi-input multi-output antenna system includes a substrate 10 and a first metal member 11 as a radiator. And a second metal member 12.

The substrate 10 can be a substrate 10 of a mobile terminal such as a mobile phone, and has a length direction and a width direction. The shape of the substrate 10 can be elliptical or rectangular. When the mobile terminal is a mobile phone, the substrate 10 is preferably a rectangular substrate 10 in order to adapt to the shape of the mobile phone. Wherein, the substrate 10 has a radiation pattern along the length direction, and the radiation pattern is similar to the planar dipole antenna in the extension direction, which we call In the vertical dipole mode, the vertical dipole mode has a radiation frequency of about 900 MHz, and the vertical dipole mode is easily excited by the electric antenna loaded thereon, but the orthogonal multi-antenna cannot be generated by using only this radiation mode. System, therefore, the present application creates an orthogonal radiation pattern at the same or similar frequencies by utilizing the width direction of the substrate 10. However, the radiation frequency due to the radiation pattern of the substrate 10 in the width direction is usually around 1.8 GHz. In order to reduce the radiation frequency of the radiation mode of the substrate 10 in the width direction, the present application realizes the loading of the capacitor by providing the opposing first metal member 11 and the second metal member 12 in the width direction of the substrate 10, thereby effectively reducing the capacitance. The radiation frequency of the radiation mode of the substrate 10 in the width direction is made close to the radiation frequency of the substrate 10 in the longitudinal direction, that is, operating below 1 GHz, so that the radiation pattern of the substrate 10 in the width direction and the radiation of the substrate 10 along the length direction are made. The mode is orthogonal.

Specifically, the first metal member 11 and the second metal member 12 have a gap with the substrate 10, and the first metal member 11 has a first feeding point 110. The first feeding point 110 and the substrate 10 are disposed between the first metal member 11 and the substrate 10. The first matching circuit 13 has two sides of the first matching circuit 13 electrically connected to the first feeding point 110 and the substrate 10, and the second metal member 12 has a second feeding point 120, and the second feeding point 120 and the first feeding point A second matching circuit 14 is disposed between the two substrates 10, and two sides of the second matching circuit 14 are electrically connected to the second feeding point 120 and the substrate 10, respectively. In the present application, the diagonal pattern of the radiation pattern of the substrate 10 in the width direction and the radiation pattern of the substrate 10 along the length direction can be excited by the first feeding point 110 and the second feeding point 120, respectively. The two diagonal modes are also approximately orthogonal. Thus, the present application constructs two mutually orthogonal antennas by the first metal member 11 and the second metal member 12, the correlation coefficient of which is only about 0.12.

In the above structure, the present application makes full use of the radiation mode of the substrate 10 itself, so that the designed multi-input multi-output antenna system has good orthogonality, low correlation coefficient, small mutual coupling, high efficiency, and thus can be extremely large. Improve the data transmission rate of the communication system. In addition, the multi-input multi-output antenna system has strong electromagnetic compatibility, so that the surrounding environment, including hands, heads, etc., has less interference when approaching the antenna.

In the present application, the substrate 10 may be a substrate 10 having a plurality of metal layers or a metal substrate 10 having a single metal layer, which may include a first feed source, a second feed source, and a connection ground, which is the substrate 10 The first feeding point 110 can be connected to the grounding source and the first feeding source through the first matching circuit 13, and the second feeding point 120 can be connected to the connecting ground and the second feeding source respectively through the second matching circuit 14. To achieve matching of multiple input multiple output antenna systems.

In order to ensure that the antenna formed by the first metal member 11 and/or the second metal member 12 can achieve the best matching effect while maintaining the structure, the first matching circuit 13 and/or the second matching in the present application can be matched. The circuit 14 is designed as an L-type matching circuit. As shown in FIG. 2, the first matching circuit 13 and the second matching circuit 14 are both L-type matching circuits, and the first matching circuit 13 and the second matching circuit 14 are explained. Referring collectively as a matching circuit, the first feed point 110 and the second feed point 120 are collectively referred to as a feed point, and the first feed and the second feed are collectively referred to as a feed: the matching circuit includes a parallel connection to the substrate 10 and the feed point. Between the inductor component, the capacitor component, the first interface 19 and the second interface 20, the feed point can be connected to the ground through the capacitor component, and the feed point can be connected to the feed through the inductor component, that is, the feed point and The first interface 19 is connected, and the second interface 20 is connected to the feed. The first matching circuit 13 and the second matching circuit 14 can also adopt a plurality of matching circuits such as single component matching and pi type matching according to actual bandwidth and frequency requirements.

It is worth noting that the feed point can be connected to the ground through the inductor, and the feed point is connected to the feed through the capacitor.

In the present application, the multiple input multiple output antenna system may further include a first insulating support plate 17 and a second insulating support plate 18, and the first insulating support plate 17 and the second insulating support plate 18 may respectively be opposite to the long sides of the substrate 10. Connecting, wherein the first insulating support plate 17 is printed with the first metal member 11, and the second insulating support plate 18 is printed with the second metal member 12, by providing the first insulating support plate 17 and the second insulating support plate 18. The first metal member 11 and the second metal member 12 are supported in the housing of the mobile terminal and cooperate with the substrate 10 to form an antenna system. It should be noted that if the middle frame of the mobile terminal is made of an insulating material, the two long sides of the middle frame can be used as the first insulating support plate 17 and the second insulating support plate 18, so that the multiple input can be reduced. The space occupied by the output antenna system facilitates the integration of other modules in the mobile terminal and is inexpensive.

The longitudinal cross-sectional area of the first metal member 11 and/or the longitudinal cross-sectional area of the second metal member 12 gradually decreases in a direction perpendicular to the substrate 10, wherein the longitudinal cross-section is a section parallel to the substrate 10. This design can increase the impedance matching bandwidth of the antenna formed by the first metal piece and/or the second metal piece.

Preferably, the two opposite sides of the first metal member 11 along the length direction of the substrate 10 are asymmetrically disposed with respect to the center plane of the first metal member 11, and/or the second metal member 12 is along the length direction of the substrate 10. The opposite side faces are asymmetrically disposed with respect to the center plane of the first metal member 11; wherein the center surface is a surface that is perpendicular to the substrate 10 while extending in the width direction of the substrate 10. This design increases the impedance matching bandwidth of the antenna formed by the first metal member 11 and/or the second metal member 12.

Preferably, the first feed point 110 may be offset from the center of the first metal member 11 which is the midpoint of the line between the two points of the first metal member 11 furthest along the length direction, and/or The second feed point 120 can be offset from the center of the second metal member 12, which is the midpoint of the line between the two points furthest along the length of the second metal member 12. This design allows the antenna formed by the first metal member 11 and/or the second metal member 12 to have a dual frequency mode of operation, i.e., the first metal member 11 and/or the second metal member 12 can operate in a plurality of frequency bands.

Further, the first feeding point 110 and the second feeding point 120 are disposed opposite to each other in the width direction, while avoiding the coincidence of the diagonal radiation patterns excited by the first feeding point 110 and the second feeding point 120. So that the two diagonal radiation patterns are more orthogonal, so that the correlation coefficients of the two antennas constructed by the first metal member 11 and the second metal member 12 are smaller, thereby greatly improving the data transmission rate of the communication system. .

According to an embodiment of the present application, the first groove 15 and/or the second groove 16 are opened on the substrate 10 along the length thereof, and the first groove 15 is coupled with the first metal member 11 and/or The second groove 16 is coupled to the second metal member 12 to form a grooved antenna, such that the design further increases the operating bandwidth of the antenna formed by the first metal member 11 and/or the second metal member 12. The first groove 15 and the second groove 16 may be an L-shaped structure, a T-shaped structure or an H-shaped structure.

Specifically, the first metal member 11 can be divided into a first segment 111 and a second segment 112 by the first feeding point 110. The length of the first segment 111 is greater than the length of the second segment 112 along the length direction. The slot 15 is coupled to the first segment 111, i.e., the slot antenna is formed at a low frequency portion to generate an additional radiation pattern that is similar to the frequency of the radiation pattern of the substrate 10 along the length direction, forming a double resonance phenomenon that can increase the first The bandwidth of the antenna formed by the metal member 11. Similarly, the second metal member 12 can be divided into the third segment 121 and the fourth segment 122 by the second feeding point 120. The length of the third segment 121 is greater than the length of the fourth segment 122 along the length direction, and the second groove 16 is coupled to the third segment 121, that is, a slot antenna is formed at a low frequency portion to generate an additional radiation pattern which is similar to the frequency of the radiation pattern of the substrate 10 along the length direction to form a double resonance phenomenon, which can increase the second metal The bandwidth of the antenna formed by piece 12.

The present application further provides a mobile terminal comprising a housing and the multiple input multiple output antenna system of any of the above embodiments, the multiple input multiple output antenna system being disposed in the housing.

A preferred embodiment of the present application is described in detail below:

A multi-input multi-output multi-antenna system applicable to mobile phones, the multi-input and multi-output multi-day The wire system comprises: a substrate, two metal parts, two grooves and two matching circuits. The following is a series of specific examples of the multi-input multi-output multi-antenna system with the substrate as the mobile phone substrate, the metal parts as T-shaped metal parts, the grooved L-shaped groove, and the matching circuit as the two-element L-type matching circuit. parameter.

As shown in FIG. 3, the dielectric layer thickness of the substrate is 0.8 mm, and a glass cloth substrate medium having a dielectric constant of 4.2 and a loss tangent value of 0.02 is used. The material of the metal layer of the substrate is 5.8e+007s/m. Copper. And the size of the substrate is 135 mm x 65 mm.

It should be noted that the radiation of the MIMO system of the present application depends on the entire substrate and the orthogonal mode formed by the substrate and the metal member, the dielectric constant and loss of the dielectric layer of the substrate, and the size of the substrate within a reasonable range. Etc. does not have a serious impact on the radiation frequency.

The total length of the metal member is 106 mm, and the feed point is offset from the center of the T-shaped metal strip, which is the midpoint of the line between the two points of the metal member along the longest direction, the feed point will be metal The piece is divided into a growing section and a short section. Specifically, the long length L1 of the metal piece is 78 mm, working in a low frequency band of 900 MHz, and the length L2 of the short section is 28 mm, and is operated in a high frequency band of 1800 MHz. The feeding point of the metal piece is a metal piece, the metal piece is square, and the width h2 is 2 mm. Wherein, the metal parts form a curved surface along which the gradual curve conforms to the semi-elliptical trajectory along the two sides of the length direction of the substrate, and the sizes of the gradual ellipse of the two sides are different, and the bandwidth of the antenna can be appropriately increased according to the impedance matching condition. The metal member is printed on an insulating support plate having a height h of 7 mm.

The groove is located directly under the metal piece, and the groove has a width of 2 mm, and the groove has a distance of 1 mm from the edge of the substrate, that is, the sum of the width of the groove and the distance of the groove from the edge of the substrate Ws It is 3mm, the length Ls of the groove is 65mm, and the groove forms a slot antenna with the metal piece, and operates in the 900MHz frequency band to form a large bandwidth. Among them, the feeding of the metal piece also provides a feed for the slot antenna and achieves a good match.

The matching circuit has a series inductance of 5.2nH and a shunt capacitance of 5pF. The matching circuit is connected to the inner conductor of the 50ohm RF connector, that is, the inner conductor of the 50ohm RF connector is connected to the feed, and the outer conductor of the RF connector is directly connected to the substrate. Connected to the ground, the feeder design of the feeder can be redesigned according to the specific connector model.

According to the above parameter values, a simulation example of the multi-input multi-output antenna system operating near 900 MHz is given, as shown in Fig. 4, Fig. 5a and Fig. 5b, and the solid line in Fig. 4 indicates the antenna formed by the metal parts. The reflection coefficient, the dotted line indicates the transmission coefficient, and the -6dB impedance bandwidth of the antenna system is 855-955MHZ in the low frequency range, which is in the high frequency range. At 1675-1810MHz, the isolation between the antennas is greater than 15dB in the low frequency range and greater than 10dB in the high frequency range. As shown in Fig. 5a and Fig. 5b, the pattern between the antennas has obvious orthogonality. By calculating the envelope correlation coefficient between the patterns, the correlation coefficient of the antenna is obtained in the low frequency range of less than 0.12 in the high frequency range. Less than 0.2, the radiation efficiency in the passband is between 80.3% and 92%.

In summary, it can be seen that each antenna in the multi-input multi-output antenna system has a large bandwidth, and the efficiency in the bandwidth range is high, and the mutual coupling between the antennas is small, which is apparent from the antenna pattern. The antenna formed by the metal member excites the mixed radiation mode of the transverse dipole mode and the vertical dipole mode, and due to the different feed positions, the radiation modes excited by the two feeds are respectively distributed along two diagonal lines. The orthogonal mode. Therefore, the correlation between the antennas in the MIMO system is low, and the data transmission rate of the communication system can be greatly improved.

The above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and various changes and modifications may be made to the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application are intended to be included within the scope of the present application.

Claims

A multiple input multiple output antenna system, comprising: a substrate having a length direction and a width direction, and first and second metal members disposed opposite to each other in a width direction of the substrate, the first metal member The second metal member and the substrate are both radiators of the multiple input multiple output antenna system, and the first metal member and the second metal member both have a gap with the substrate.

a first feeding point is disposed on the first metal member, and a first matching circuit is disposed between the first feeding point and the substrate, and two sides of the first matching circuit are respectively associated with the first feeding The electrical point is electrically connected to the substrate,

a second feeding point is disposed on the second metal member, and a second matching circuit is disposed between the second feeding point and the second substrate, and two sides of the second matching circuit are respectively associated with the first The two feed points are electrically connected to the substrate.
The multiple input multiple output antenna system according to claim 1, wherein

The longitudinal cross-sectional area of the first metal member and/or the longitudinal cross-sectional area of the second metal member gradually decreases in a direction perpendicular to the substrate, the longitudinal cross-section being a cross section parallel to the substrate.
The multiple input multiple output antenna system according to claim 2, wherein

The opposite sides of the first metal member along the length direction of the substrate are asymmetrically disposed with respect to a center plane of the first metal member, and/or

The two opposite sides of the second metal member along the length direction of the substrate are asymmetrically disposed with respect to a central surface of the first metal member;

The central surface is a surface that is perpendicular to the substrate while extending along the width direction of the substrate.
The multiple input multiple output antenna system according to claim 1, wherein

The first feed point is offset from a center of the first metal piece, the center being a midpoint of a line between two points of the first metal piece farthest along the length direction, and /or

The second feed point is offset from a center of the second metal piece, the center being a midpoint of a line between two points of the second metal piece that are furthest along the length direction.
The multiple input multiple output antenna system according to claim 4, wherein said first feed point and said second feed point are disposed facing each other in said width direction.
The multiple input multiple output antenna system according to claim 4, wherein a first groove coupled to the first metal member and/or the second portion is opened on the substrate along a length direction thereof A second groove to which the metal piece is coupled.
The multiple input multiple output antenna system according to claim 6, wherein

The first metal member is divided into a first segment and a second segment by the first feeding point, and along the length direction, a length of the first segment is greater than a length of the second segment, the first a segment coupled to the first groove; and/or

The second metal piece is divided into a third segment and a fourth segment by the second feeding point, along the length direction, the length of the third segment is greater than the length of the fourth segment, the third A segment is coupled to the second groove.
The multiple input multiple output antenna system according to any one of claims 1 to 5, characterized in that at least one of the first matching circuit and the second matching circuit is an L-type matching circuit.
The multiple input multiple output antenna system according to any one of claims 1 to 5, further comprising a first insulating support plate printed with the first metal member and printed with the second metal A second insulating support plate of the piece, the first insulating support plate and the second insulating support plate are both connected to the substrate.
A mobile terminal, comprising the multiple input multiple output antenna system and the housing according to any one of claims 1 to 9, the multiple input multiple output antenna system being disposed within the housing.