WO2018119944A1 - Multi-input multi-output antenna system and mobile terminal - Google Patents

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 MIMO antenna system comprises a substrate and two or more antenna structures. The substrate comprises a feed source and a grounding point. Each of the antenna structures comprises: a first layer structure; and a second layer structure arranged between the first layer structure and the substrate. The first layer structure comprises a first metal attachment plate and a first short-circuited component. The first metal attachment plate comprises a feed point connected to the feed source and a first grounding feed point. Two ends of the first short-circuited component are connected to the first grounding feed point and the grounding point, respectively. The second layer structure comprises a second metal attachment plate coupled to the first metal attachment plate and a second short-circuited component. The second metal attachment plate comprises a second grounding feed point. Two ends of the second short-circuited component are connected to the second grounding feed point and the grounding point, respectively. By coupling the first metal attachment plate and the second metal attachment plate, the embodiment can reduce coupling between respective antenna structures, thereby increasing isolation between the respective antenna structures.

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

Multiple input multiple output technology is a key technology in the fourth generation and future mobile communication field, which can increase the transmission rate of the system without increasing the spectrum of output power. However, as mobile devices become more compact and the requirements for functional modules increase, the space left in the mobile devices for antennas becomes smaller and smaller, and the antennas are required to have multi-frequency operation characteristics.

Because the PIFA antenna (Planar Inverted F Antenna) has the characteristics of small size, multi-band operation, omnidirectional radiation and low human absorption rate, it has become a widely used antenna type in mobile terminals such as mobile phones. . However, for highly integrated cell phone antennas, the quarter-wavelength PIFA antenna is still large. In addition, during the operation of the PIFA antenna, a strong current is generated on the substrate. When a multi-input multi-output antenna system is used, and the distance between the antennas is close, the current flows from the port of one antenna to The port of the other antenna causes a large coupling, which greatly reduces the isolation.

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 problems.

A first aspect of the present application provides a multiple input multiple output antenna system including: a substrate having at least two antenna structures, the substrate having a feed and a ground point, the antenna structure including a first layer structure and a second a layer structure, the second layer structure is spaced between the first layer structure and the substrate,

The first layer structure includes a first metal patch having a feed point and a first ground feed point, and a first ground feed point, the feed point being connected to the feed source, First short circuit Two ends of the component are respectively connected to the first ground feed point and the ground point,

The second layer structure includes a second metal patch and a second short circuit component, the second metal patch is coupled to the first metal patch, and the second metal patch has a second ground feed point, Both ends of the second short circuit element are respectively connected to the second ground feed point and the ground point.

Preferably, the first metal patch comprises a plurality of metal wires, and the plurality of metal wires are sequentially connected to form a spiral metal patch.

Preferably, the plurality of metal wires comprise a metal connection line having the first ground feed point and other metal lines other than the metal connection line, the metal connection line having a diameter larger than a diameter of the other metal line .

Preferably, the feeding point is disposed on the metal connecting line, and the feeding point is spaced apart from the first ground feeding point.

Preferably, there is at least two spacing values between the first ground feed point and the feed point.

Preferably, the second ground feed point is disposed on a portion of the second metal patch away from the first ground feed point and the feed point.

Preferably, the first metal patch is disposed in parallel with the second metal patch.

Preferably, the first layer structure further comprises a feeding probe, and two ends of the feeding probe are respectively connected to the feeding source and the feeding point.

Preferably, the radiation pattern between at least two of said antenna structures is orthogonal.

A second aspect of the present application provides a mobile terminal comprising the multiple input multiple output antenna system of any of the above.

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

The multiple input multiple output antenna system provided by the present application has an antenna structure including a first layer structure and a second layer structure, the second layer structure is disposed between the first layer structure and the substrate, and the second layer structure is The two metal patch is coupled with the metal patch of the first layer structure, and the second layer structure is coupled with the first layer structure. On the one hand, the loading of the capacitor is realized, so that the antenna structure achieves good impedance matching at the resonant frequency. On the other hand, the current on the substrate is confined around the antenna structure, the current of the antenna structure is prevented from flowing to the ports of other antenna structures, and the coupling between the antenna structures is reduced, thereby increasing the structure between the antenna structures. The isolation greatly increases the data transmission rate of the communication system.

It should be understood that the above general description and the following detailed description are merely exemplary and This application cannot be restricted.

DRAWINGS

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

Figure 2 is a dimensional representation of the multiple input multiple output antenna system shown in Figure 1;

3 is a schematic structural diagram of a first layer structure and a second layer structure of an antenna structure in a multiple input multiple output antenna system according to an embodiment of the present application;

Figure 4 is a view showing the first layer structure, the second layer structure and the dimensional representation between them in Figure 3;

FIG. 5 is a schematic top plan view of the antenna structure shown in FIG. 3; FIG.

Figure 6 is a dimensional representation of the multiple input multiple output antenna system shown in Figure 5;

7 is a frequency spectrum diagram of an antenna structure in a multiple input multiple output antenna system according to an embodiment of the present application;

FIG. 8 is a diagram showing relationship between S parameters and frequency of simulation and testing of an antenna structure in a multiple input multiple output antenna system according to an embodiment of the present application; FIG.

FIG. 9 is a measured radiation pattern of two resonance points in a multiple input multiple output antenna system according to an embodiment of the present application.

Reference mark:

1-antenna structure;

11-first metal patch;

12-feed probe;

13-first short circuit component;

14-second metal patch;

15-second short circuit component;

2-substrate.

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 , FIG. 3 and FIG. 5 , the embodiment of the present application provides a multi-input and multi-output day. A line system comprising a substrate 2 and at least two antenna structures, the radiation patterns between the at least two antenna structures being orthogonal to enhance polarization diversity between the multiple antennas, which facilitates enhancing the transmission rate of the multiple input multiple output antenna system.

The substrate 2 has a feed and a grounding point. The antenna structure comprises a first layer structure and a second layer structure. The first layer structure comprises a first metal patch 11 and a first shorting element 13, and the first metal patch 11 has a feeding a point and a first ground feed point, the feed point is connected to the feed source, and the two ends of the first short circuit element 13 are respectively connected with the first ground feed point and the ground point, and the first layer structure can form a planar inverted F antenna structure. The main radiator of the antenna structure, and the second layer structure is disposed between the first layer structure and the substrate 2, the second layer structure includes the second metal patch 14 and the second short-circuiting element 15, the second metal patch 14 has a second ground feed point, two ends of the second short circuit element 15 are respectively connected with the second ground feed point and the ground point, and the second metal patch 14 is fed by being coupled with the first metal patch 11 so that The design not only realizes the loading of the capacitor, but also achieves good impedance matching of the antenna structure at the resonant frequency, and can also limit the current on the substrate 2 around the antenna structure, avoiding the current of the antenna structure flowing to the port of other antenna structures. , decrease Coupling between the antenna structure, thereby increasing the isolation between the antenna structure, which greatly improves the data transfer rate of the communication system.

The first shorting element 13 may be a shorting probe or a shorted metal plate according to a specific resonant frequency and matching condition of the antenna structure, and the second shorting element 15 may be a shorting probe or a short metal plate.

Preferably, the first metal patch 11 includes a plurality of metal wires, and the plurality of metal wires are sequentially connected to form a spiral metal patch, that is, the shape of the first metal patch 11 is spiral, and the first is guaranteed. When the metal patch 11 is approximately a quarter wavelength of the low frequency resonant frequency of the multiple input multiple output antenna system, the first metal patch can be greatly reduced by designing the first metal patch 11 as a spiral metal patch. The overall length of the 11 allows the antenna structure to be designed to facilitate integration of other components within the mobile terminal. Since the spiral structure itself can generate strong inductivity, the second metal patch 14 of the second layer structure is coupled with the first metal patch 11 to achieve capacitive loading, so that the antenna structure resonates and forms an LC resonant circuit. So that the antenna structure achieves good matching at the resonant frequency, and can limit the current on the substrate 2 around the antenna structure, avoiding the current of the antenna structure flowing to the ports of other antenna structures, and reducing the antenna structure. The coupling between them increases the isolation between the antenna structures.

Specifically, as shown in FIG. 7 , the broken line indicates the antenna structure in the prior art that does not load the second metal patch 14 , and the solid line indicates the antenna structure of the second metal patch 14 in the present application, and the figure is at 0.9 GHz. In the vicinity, the input impedance value of the antenna structure in the prior art is about 80 ohms, and the input impedance value of the antenna structure of the present application is close to 0, and the inductance is greatly reduced. At the same time, in the present application, by providing the second metal patch 14, the second metal patch 14 can share most of the current, so that the current on the corresponding substrate 2 is reduced, and the current of the antenna structure is prevented from flowing to other antenna structures. The port reduces the coupling between the antenna structures.

It should be noted that the first metal patch 11 can also form a spiral metal patch by means of notching. Preferably, the first metal patch 11 is a unitary structure to ensure the first metal patch 11 The structural strength ensures the stability of the antenna structure.

Further, the plurality of metal lines include a metal connection line having a first ground feed point and a metal line other than the metal connection line, the metal connection line having a diameter larger than that of the other metal lines, so as to ensure the first metal While the patch 11 occupies a small space, the area of the first ground feed point can be increased, thereby facilitating the connection of the first short-circuiting element 13 with the first metal patch 11.

In this application, the feeding point of the first metal patch 11 is spaced apart from the first ground feeding point, and the feeding point may be disposed on the metal connecting line adjacent to the first ground feeding point, so that the design is such that The feed point can form a good excitation and achieve impedance matching.

Preferably, the first ground feed point and the feed point have at least two pitch values, that is, the distance between the first ground feed point and the feed point is not fixed and can be adjusted through Adjusting the spacing between the first ground feed point and the feed point adjusts the impedance matching of the antenna structure.

In addition, the second ground feed point on the second metal patch 14 of the present application is disposed away from the first ground feed point and the feed point, wherein the relative position of the second ground feed point and the first ground feed point and the feed point Adjustable to accommodate adjustment of impedance matching.

Optionally, the first metal patch 11 is disposed in parallel with the second metal patch 14 to ensure the coupling strength between the second metal patch 14 and the first metal patch 11, so that the second layer structure and the first layer structure Achieve a good match.

According to an embodiment of the present application, the first layer structure further includes a feeding probe 12, and two ends of the feeding probe 12 are respectively connected to the feeding source and the feeding point, and by providing the feeding probe 12, the first step can be reduced. The difficulty of connecting the feed point of the layer structure to the feed. Preferably, the feed probe 12 is an L-type feed probe 12, and the best matching effect can be achieved while maintaining a simple structure.

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

As shown in FIG. 1 to FIG. 6, a multiple input multiple output antenna system applicable to a mobile phone, the multiple input multiple output antenna system includes: a substrate 2 and two antenna structures, each antenna structure including a first metal patch 11. Feed probe 12, first shorting element 13, second shorting element 15 and second metal patch 14. Hereinafter, the substrate 2 is a mobile phone substrate, the first metal patch 11 is a spiral metal patch, the first shorting element 13 is a first shorting probe, and the second shorting element 15 is a second shorting probe, and the second metal patch is used. Taking a rectangular metal patch as an example, a series of specific parameters of the multi-input multi-output antenna system are given.

The size of the mobile phone substrate is 130 mm x 60 mm. The substrate is made of a metallized substrate, and the dielectric layer has a dielectric thickness of 0.8 mm. The FR4 plate having a dielectric constant of 4.2 and a loss tangent of 0.02 can be used, and the material of the metal layer can be 5.8e+007s/ The copper of m, and the shape of the base of the mobile phone may be rectangular, and the length and width may be 130 mm × 60 mm.

The two antenna structures are located at the same end of the base of the mobile phone and are placed orthogonally, and the spacing between adjacent sides between the two antenna structures is 15 mm.

The spiral metal patch has a total length of 86.5 mm and a spiral width of 0.5 mm. The length of the patch formed after bending is 17.5 mm, which is equivalent to one-twentieth wavelength and 5.5 mm wide. At one-sixtieth of a wavelength, the lateral dimensions of the antenna structure are greatly reduced. And the height of the spiral metal patch from the base of the mobile phone is 6 mm. The first shorting probe is placed at one end of the spiral, a distance of 123 mm from the feeding probe. The rectangular metal patch is disposed in parallel with the spiral metal patch, and the distance between the rectangular metal patch and the spiral metal patch is 0.6 mm to form an effective capacitive coupling, and the length of the rectangular metal patch is 8.5 mm. The width is 4.5mm.

For the parameters shown in FIG. 2, FIG. 4 to FIG. 6, the preferred values of Table 1 are preferred in the embodiment of the present application:

Table I

parameter	size
L1	17.5mm
L2	8.5mm
W1	5.5mm
W2	4mm
H1	6mm

H2	5.4mm
S1	1mm
S2	0.5mm
d	1mm
Lg	130mm
Wg	60mm
D2	15mm

Referring to Table 1, a simulation example of the antenna structure operating near 900 MHz and 2.4 GHz is given. As shown in Figure 8 and Figure 9. The -6dB impedance bandwidth of the antenna structure is 880-945MHz in the low frequency range and 2.39GHz-2.48GHz in the high frequency range. The isolation between the tested antenna structures is greater than 34dB and 28dB at low and high frequencies, respectively. It indicates that the mutual coupling between the antenna structures is low, and the pattern of the antenna structure basically covers the upper half space. The average gain measured in the low frequency range is 0.4 dB, and the maximum gain is 1.62 dB. In the high frequency operating range, the average gain is 1.1 dB, and the maximum direction gain is 2.13 dB. The efficiency of the antenna structure in the two frequency bands is 40.9% and 62.8%, respectively.

In summary, it can be seen that the multi-input multi-output antenna system realizes dual-frequency resonance in the case where the antenna structure size is small. And because of the current limiting effect of the second metal patch 14, there is good isolation between the antenna structures. No decoupling structure or impedance matching circuit is required between the antenna structures, which saves space and cost for the entire multi-input multi-output antenna system.

The present application also provides a mobile terminal comprising the multiple input multiple output antenna system as described in any of the above embodiments.

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 (10)

1. A multiple input multiple output antenna system, comprising: a substrate and at least two antenna structures, the substrate having a feed and a ground point, the antenna structure comprising a first layer structure and a second layer structure, a second layer structure is disposed between the first layer structure and the substrate,

   The first layer structure includes a first metal patch having a feed point and a first ground feed point, and a first ground feed point, the feed point being connected to the feed source, Two ends of the first shorting element are respectively connected to the first ground feed point and the ground point,

   The second layer structure includes a second metal patch and a second short circuit component, the second metal patch is coupled to the first metal patch, and the second metal patch has a second ground feed point, Both ends of the second short circuit element are respectively connected to the second ground feed point and the ground point.
2. The multiple input multiple output antenna system according to claim 1, wherein

   The first metal patch includes a plurality of metal wires, and the plurality of metal wires are sequentially connected to form a spiral metal patch.
3. The multiple input multiple output antenna system according to claim 2, wherein the plurality of metal lines comprise a metal connection line having the first ground feed point and other metal lines other than the metal connection line, The diameter of the metal connecting wire is larger than the diameter of the other metal wire.
4. The multiple input multiple output antenna system according to claim 3, wherein the feed point is disposed on the metal connection line, and the feed point is spaced apart from the first ground feed point.
5. The multiple input multiple output antenna system according to claim 4, wherein said first ground feed point and said feed point have at least two pitch values.
6. The multiple input multiple output antenna system according to claim 4, wherein

   The second ground feed point is disposed on a portion of the second metal patch away from the first ground feed point and the feed point.
7. The multiple input multiple output antenna system according to any one of claims 1 to 6, wherein

   The first metal patch is disposed in parallel with the second metal patch.
8. The multiple input multiple output antenna system according to any one of claims 1 to 6, wherein the first layer structure further comprises a feed probe, and both ends of the feed probe are respectively The feed is connected to the feed point.
9. The multiple input multiple output antenna system according to any one of claims 1 to 6, wherein

   The radiation pattern between at least two of the antenna structures is orthogonal.
10. A mobile terminal characterized by comprising the multiple input multiple output antenna system according to any one of claims 1 to 9.

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