Antenna system and mobile terminal

The present disclosure provides an antenna system, including a mainboard having a system ground, a metal frame disposed around the mainboard and being closed-loop without any breakpoints, a first wire, a second wire, a third wire, a feed terminal, and a ground terminal. The system ground is electrically connected to the metal frame. The first wire is connected to the feed terminal and is opposite to and spaced apart from the metal frame, so that the first wire forms a first antenna unit. The second wire is connected to the ground terminal and is spaced apart from the first wire, and the second wire and the first wire are at least partially opposite, so that the second wire and the first wire are coupled with each other, to form a second antenna unit.

TECHNICAL FIELD

The present disclosure relates to the field of wireless communications technologies, more particular to an antenna system and a mobile terminal.

BACKGROUND

Currently, communications devices having a metal housing, such as mobile phones, have become a mainstream structure of major brands of mobile phones. When an antenna of a mobile phone is designed, slits are usually disposed in a metal frame of the metal housing, to satisfy an antenna band performance requirement. However, an excessively large width of the slit will influence the structural strength and appearance texture of the entire mobile phone; an excessively small width will cause parts on two sides of the slit to be coupled with each other, and a smaller width of the slit indicates stronger coupling, influencing the antenna performance severely. Apparently, it is quite difficult for the metal housing of a slit type to meet requirements for structural strength, appearance texture, and antenna performance of the mobile phone at the same time

Therefore, it is actually necessary to provide a new antenna to resolve the above problems.

DETAILED DESCRIPTION

The following clearly and completely describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure.

As shown inFIG. 1toFIG. 5, an embodiment of the present disclosure provides a mobile terminal such as a mobile phone or a personal digital assistant. The mobile terminal includes an antenna system.

Specifically, the antenna system includes a mainboard1having a system ground10, a metal frame2disposed around the mainboard1and being closed-loop without any breakpoints, a first wire3, a second wire4, a third wire5, a feed terminal6, and a ground terminal7. Generally, the system ground10may be a metal layer laid on the mainboard1, and the system ground10is electrically connected to the metal frame2, so that the metal frame2is grounded. The metal frame is of an annular structure, and no breakpoint exists along the periphery of the metal frame2. The antenna system further includes a feed point disposed on the mainboard1and a ground point connected to the system ground10, where the feed terminal6is connected to the feed point and the ground terminal7is connected to the ground point.

The first wire3is connected to the feed terminal6and is opposite to and spaced apart from the metal frame2, so that the first wire3and the metal frame2are coupled with each other, to form a first antenna unit.

The second wire4is connected to the ground terminal7and is spaced apart from the first wire3, and the second wire4and the first wire3are at least partially opposite. Generally, a part of the second wire4far away from the ground terminal7is opposite to a part of the first wire3far away from the feed terminal6, so that the second wire4and the first wire3are coupled with each other, to form a second antenna unit. Generally, a shape of the first wire3is roughly the same as that of the second wire4.

One end of the third wire5is connected between the feed terminal6and an end of the first wire3, and the other end is connected to the metal frame2, so that the first wire3is electrically connected to the metal frame2, to form a third antenna unit.

In the antenna system, the first antenna unit is formed by the first wire3, the second antenna unit is formed by the second wire4and the first wire3being opposite to, spaced apart from, and coupled with each other, and the third antenna unit is formed by the third wire5being connected to the first wire3and the metal frame2, thereby implementing radiation of the antenna system. In the antenna system, breakpoints do not need to be disposed in the metal frame2. The metal frame2is of a closed-loop structure, thereby strengthening a structural strength of the entire mobile terminal and improving an appearance defect of having slits in the metal frame in the existing technology. Because precise matching on sizes of slits is not required, the production costs and production hours are largely reduced, and a large quantity of tolerance control areas are reduced. In this way, the yield of the products can be improved and the actual antenna performance is not lowered.

The first wire3, the second wire4, the third wire5, the feed terminal6, and the ground terminal7are each of a sheet-shaped structure. The first wire3, the second wire4, and the third wire5are disposed in a same plane, and the feed terminal6and the ground terminal7are disposed in a plane perpendicular to the plane in which the first wire3is disposed.

Generally, the first wire3is disposed at an outer side of the second wire4and is disposed around the second wire4. Therefore, the shape of the first wire3is roughly the same as that of the second wire4. Specifically, the first wire3includes a first connection portion31of an L-shape and a first extension portion32of an L-shape bending and extending from one end of the first connection portion31, and the first connection portion31and the first extension portion32define a rectangular structure having a notch. The other end of the first connection portion31is connected to the feed terminal6. The second wire4includes a second connection portion41of a long strip shape and a second extension portion42of an L-shape bending and extending from one end of the second connection portion41, and the other end of the second connection portion41is connected to the ground terminal7. The second wire4is disposed in the rectangular structure defined by the first connection portion31and the first extension portion32. The third wire5is vertically connected to an intermediate position of the first connection portion31.

There may be one or more joints of the system ground10and the metal frame2.

Optionally, the metal frame2includes a top frame21and two side frames22disposed opposite to two ends of the top frame21. A clearance area20is disposed between the system ground10and the top frame21, and the first wire3, the second wire4, and the third wire5are disposed in the clearance area20. The system ground10is connected to one of the side frames22, a gap30is left between the system ground10and the other of the side frames22, and the gap30is in communication with the clearance area20. Preferably, the third wire5is of a long strip shape, connected to the top frame21, and parallel to the side frames22. Because the first wire3, the second wire4, and the third wire5are usually flexible printed circuit (FPC) antenna wires or laser direct structuring (LDS) antenna wires, the antenna system further includes a holder (not shown) made of a non-metal material, for example, the holder is a plastic part. The first wire3, the second wire4, and the third wire5are disposed in the clearance area20through the holder, to support the first wire3, the second wire4, and the third wire5through the holder, facilitating the installation of the antenna system in the mobile terminal.

FIG. 6is a schematic diagram showing a band of an antenna system according to the present disclosure. The antenna system roughly forms three band ranges a, b, and c, where a represents the band range of the first antenna unit having an operating band of 1550 to 1620 MHz, b represents the band range of the second antenna unit having an operating band of 2400 to 2500 MHz, and c represents the band range of the third antenna unit having an operating band of 5150 to 5850 MHz.

FIG. 7is a schematic diagram showing antenna efficiency of an antenna system according to the present disclosure. The test result indicates that the antenna efficiency of the antenna system is greater than 65% in the entire operating band (1550 to 1620 MHz, 2400 to 2500 MHz, and 5150 to 5850 MHz), indicating that the antenna system has good antenna performance.

Compared with the related art, the antenna system and the mobile terminal provided in the present disclosure have the following beneficial effects:

1) The first antenna unit is formed by the first wire, the second antenna unit is formed by the second wire and the first wire being opposite to, spaced apart from and coupled with each other, and the third antenna unit is formed by the third wire being connected to the first wire and the metal frame, thereby implementing radiation of the antenna system; in the antenna system, breakpoints do not need to be disposed in the metal frame; the metal frame is of a closed-loop structure, thereby strengthening a structural strength of the entire mobile terminal and improving an appearance defect of having slits in the metal frame in the existing technology;

2) Because slits do not need to be disposed in the metal frame, that is, precise matching on sizes of slits is saved, the production costs and production hours are largely reduced, and a large quantity of tolerance control areas are reduced. In this way, the yield of the products can be improved and the actual antenna performance is not lowered.

The foregoing descriptions are merely embodiments of the present disclosure but are not intended to limit the patent scope of the present disclosure, an equivalent structure or equivalent procedure replacement made based on the content of the specification and the accompanying drawings of the present disclosure or directly or indirectly applied in other relevant technical fields is included in the patent protection scope of the present disclosure.