Electronic device

An electronic device including a metal element and an antenna element is provided. The antenna element is disposed on a substrate and includes a radiation portion and a connection portion. A first end of the radiation portion has a feeding point for receiving a feeding signal, and a second end of the radiation portion is an open end. A first end of the connection portion is electrically connected to the first end of the radiation portion. A second end of the connecting portion has a first ground point to be electrically connected the metal element. An orthogonal projection of the metal element on the substrate and an orthogonal projection of the antenna element on the substrate are overlapped with each other. The radiation portion is electrically connected the metal element through a second ground point.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application Ser. No. 104137449, filed on Nov. 13, 2015. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention is related to an electronic device, and particularly related to an electronic device having a metal element and an antenna element.

Description of Related Art

In recent years, electronic devices with metal touch are getting popular with consumers. Accordingly, most current electronic devices are designed with a metal back cover or a metal frame to exhibit uniqueness and appearance characteristics of the products. In addition, the electronic device is provided with an antenna element; the coupling between the antenna element and the metal back cover affects radiation characteristic of the antenna element.

To reduce the effect of the metal back cover on the antenna element, in conventional techniques, the antenna element is generally disposed to be away from the metal back cover. For example, in conventional techniques, a distance between the antenna element and the metal back cover needs to be larger than 5 mm or more. However, under the circumstances where the distance between the antenna element and the metal back cover is larger, the thickness of the electronic device increases relatively, making it difficult to achieve slim design of the electronic device.

SUMMARY OF THE INVENTION

The invention is directed to an electronic device in which an antenna element has a feeding point and a first ground point, and a radiation portion of the antenna element has a second ground point. Accordingly, with arrangement of the second ground point, the effect of metal element on the antenna element can be effectively reduced, thereby facilitating slim design of the electronic device.

In an embodiment of the invention, the electronic device includes a metal element and an antenna element. The antenna element is disposed on a substrate and includes a radiation portion and a connecting portion. A first end of the radiation portion has a feeding point for receiving a feeding signal. A second end of the radiation portion is an open end. A first end of the connecting portion is electrically connected to the first end of the radiation portion. A second end of the connecting portion has a first ground point to be electrically connected to the metal element. Furthermore, an orthogonal projection of the metal element on the substrate and an orthogonal projection of the antenna element on the substrate are overlapped with each other. The radiation portion is electrically connected to the metal element via the second ground point.

In an embodiment of the invention, the electronic device further includes a ground element. The ground element is electrically connected to the first ground point and the metal element. The radiation portion includes a first radiation arm and a second radiation arm that are electrically connected together. The first radiation arm is adjacent to an edge of the ground element, and the second radiation arm is parallel with the edge of the ground element.

In an embodiment of the invention, the feeding point is disposed in the first radiation arm, and the second ground point is disposed in the second radiation arm.

Based on the above, in the electronic device of the invention, the orthogonal projection of the metal element on the substrate and the orthogonal projection of the antenna element on the substrate are overlapped with each other. Meanwhile, the radiation portion of the antenna element receives the feeding signal via the feeding point, and the connecting portion of the antenna element is electrically connected to the metal element via the first ground point. Moreover, the radiation portion of the antenna element further has the second ground point that is electrically connected to the metal element. With such configuration, the effect of the metal element on the antenna element can be effectively reduced, thereby facilitating slim design of the electronic device.

In order to make the aforementioned features and advantages of the invention more comprehensible, embodiments accompanying figures are described in detail below.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1is a schematic view illustrating an electronic device according to an embodiment of the invention. As shown inFIG. 1, an electronic device100includes a metal element110, an antenna element120and a substrate130, and the antenna element120includes a radiation portion121and a connecting portion122. The metal element110may be, for example, a metal back cover or a portion of the metal back cover of the electronic device100. The antenna element120is disposed on the substrate130, and the substrate130is disposed on the metal element100. In other words, the antenna element120and the metal element110are spaced apart by the substrate130, and the antenna element120is opposite to the metal element110. In addition, an orthogonal projection of the metal element110on the substrate130and an orthogonal projection of the antenna element120on the substrate130are overlapped with each other.

In terms of the antenna element120, a first end of the radiation portion121has a feeding point FP1for receiving a feeding signal, and a second end of the radiation portion121is an open end. A first end of the connecting portion122is electrically connected to the first end of the radiation portion121. A second end of the connecting portion122has a first ground point GP11to be electrically connected to the metal element110. For example, the electronic device100further includes a ground element140, and the first ground point GP11of the connecting portion122may be electrically connected to the metal element110via the ground element140. With such configuration, the radiation portion121and the connecting portion122may form an inverted F antenna. That is to say, the antenna element120may be, for example, an inverted F antenna that can operate in a first band (e.g. 2.4 GHz).

It should be noted that the radiation portion121of the antenna element120further has a second ground point GP12, and the radiation portion121is electrically connected to the metal element110via the second ground point GP12. For example,FIG. 2is a sectional view illustrating the electronic device inFIG. 1in a Y-axis direction. As shown inFIG. 2, the electronic device100further includes a conductive element210. The substrate130includes a surface131and a side wall132that are adjacent to each other. The antenna element120is disposed on the surface131of the substrate130, and the conductive element210is attached to the side wall132of the substrate130. In addition, the conductive element210is electrically connected between the second ground point GP12of the radiation portion121and the metal element110.

The conductive element210may be, for example, a metal sheet, a conductive elastic piece or a pogo-pin. AlthoughFIG. 2exemplifies how the radiation portion121and the metal element110are connected to each other, it should not be construed as a limitation to the invention. For example,FIG. 3is another sectional view illustrating the electronic device inFIG. 1in the Y-axis direction. As shown inFIG. 3, the electronic device100further includes a conductive element310that may be, for example, a conductive through hole. Specifically, the conductive through hole penetrates through the substrate130, and the conductive through hole is electrically connected between the second ground point GP12of the radiation portion121and the metal element110.

In terms of operation, the antenna element120can receive the feeding signal generated by a transceiver (not shown) in the electronic device100via the feeding point FP1. Accordingly, with excitation of the feeding signal, the antenna element120can operate in a first band (e.g. 2.4 GHz). It should be pointed out that, since the radiation portion121of the antenna element120has the second ground point GP12, the effect of the metal element110on the antenna element120, namely, the mutual interference between the metal element110and the antenna element120, can be effectively reduced.

For example,FIG. 4is a Smith Chart illustrating an antenna element without a second ground point according to an embodiment of the invention.FIG. 5is a Smith Chart illustrating an antenna element having a second ground point according to an embodiment of the invention.FIG. 6is a diagram showing a return loss of an antenna element with or without a second ground point according to an embodiment of the invention. As indicated by an impedance point410inFIG. 4, under the condition that the second ground point GP12is not disposed, an impedance of the antenna element120in the first band (e.g. 2.4 GHz) is located in an inductive region, and an inductive component of the impedance of the antenna element120is high. At this time, as indicated by a return loss curve610inFIG. 6, the antenna element120cannot generate a good resonant mode in the first band (e.g. 2.4 GHz).

On the other hand, as shown by an impedance point510inFIG. 5, with arrangement of the second ground point GP12, a capacitive component of the impedance of the antenna element120increases correspondingly. Therefore, the impedance of the antenna element120in the first band (e.g. 2.4 GHz) is close to 50 ohm. At this time, as indicated by a return loss curve620inFIG. 6, the antenna element120can generate a good resonant mode in the first band (e.g. 2.4 GHz).

In other words, with the arrangement of the second ground point GP12, the effect of the metal element110on the antenna element120can be effectively reduced. That is, the arrangement of the second ground point GP12can shorten the distance between the antenna element120and the metal element110(e.g. metal back cover), and helps to achieve slim design of the electronic device100. For example, in an embodiment, the thickness of the substrate130may be less than or equal to 3 mm; that is, the distance between the antenna element120and the metal element100can be reduced to 3 mm at least.

In order to make the present invention comprehensive to those skilled in the art, an exemplary embodiment is described below which shows a detailed structure of the antenna element120. Further referring toFIG. 1, a portion of the radiation portion121and a portion of the connecting portion122are parallel with an edge141of the ground element140. Specifically, the radiation portion121includes a first radiation arm121aand a second radiation arm121bthat are electrically connected to each other, and the connecting portion122includes a first connecting arm122aand a second connecting arm122bthat are electrically connected to each other.

The first radiation arm121ais adjacent to and perpendicular to the edge141of the ground element140. The second radiation arm121bis parallel with the edge141of the ground element140. Accordingly, the first radiation arm121aand the second radiation arm121bmay be formed as an L-shape structure. In other words, the radiation portion121includes a bending, and the shape of the radiation portion121may be, for example, an L-like shape. AlthoughFIG. 1exemplifies the implementation of the radiation portion121, it should not be construed as a limitation to the invention. For instances, in another embodiment, the second radiation arm121bmay be, for example, parallel with the first radiation arm121a. That is to say, the shape of radiation portion121may be, for example, a straight-line shape.

It should be noted that the feeding point FP1may be disposed at the first end of the radiation portion121, and the second ground point GP12may be disposed at the bending of the radiation portion121. In addition, a distance between the second ground point GP12to a second end (i.e., open end) of the radiation portion121is proportional to the frequency of the first band. In other words, under the condition that the second ground point GP12is closer to the second end (i.e., open end) of the radiation portion121, the frequency of the first band in which the antenna element120operates is higher. For example, inFIG. 1, the feeding point FP1may be disposed on the first radiation arm121a, and the second ground point GP12may be disposed on the second radiation arm121b. In addition, the distance between the second ground point GP12and the second end (i.e., open end) of the radiation portion121may be, for example, ¼ wavelength of the lowest frequency of the first band.

In terms of the connecting portion122of the antenna element120, the first connecting arm122ais electrically connected to the first radiation arm121a, and the first connecting arm122ais disposed between the second radiation arm121band the edge141of the ground element140. The second connecting arm122bis electrically connected to the first connecting arm122aand the ground element140, and the second connecting arm122bis parallel with the second radiation arm121b. Viewing from another angle, the second connecting arm122band the ground element140are sequentially arranged along an X-axis direction, and the first connecting arm122afaces the second connecting arm122band the edge141of the ground element140. Moreover, the shape of the first connecting arm122amay be, for example, an inverted L-shape. The shape of the second connecting arm122bmay be, for example, a straight-line shape. Accordingly, the radiation portion121and the first connecting arm122aof the connecting portion122can form a groove with an opening facing the −X-axis direction, and the connecting portion122has another groove with an opening facing the X-axis direction.

It should be mentioned that the radiation portion121inFIG. 1can form a resonant path, such that the antenna element120can operate in the first band via the radiation portion121. In another embodiment, an adjusting portion may be further disposed in the antenna element120, such that the antenna element120can further operate in a second band. In addition, a parasitic portion may be further disposed in the antenna element120so as to adjust the bandwidth of the second band in which the antenna element120operates.

For example,FIG. 7is a schematic view illustrating an electronic device according to another embodiment of the invention. Compared to the embodiment inFIG. 1, an electronic device700inFIG. 7further includes an adjusting portion710. Specifically, the adjusting portion710is electrically connected to the radiation portion121and the connecting portion122. In other words, the adjusting portion710is electrically connected to the second radiation arm121band the first connecting arm in122a. Moreover, a distance between the adjusting portion710and the first radiation arm121ais larger than 1/10 wavelength of the lowest frequency of the first band.FIG. 8describes the diagram showing the return loss of the antenna element inFIG. 7. A return loss curve810represents a return loss under the condition where the adjusting portion710is not incorporated into the antenna element120; a return loss curve820represents a return loss under the condition where the adjusting portion710is incorporated into the antenna element120. The return loss curves810and820show that the adjusting portion710is configured to increase the bandwidth of the first band (e.g. 2.4 GHz) of the antenna element120. Apart from that, with the arrangement of the adjusting portion710, the antenna element120can further operate in the second band (e.g. 5 GHz).

FIG. 9is a schematic view illustrating an electronic device according to another embodiment of the invention. Compared to the embodiment inFIG. 7, an electronic device900illustrated byFIG. 9further includes a parasitic portion910. Specifically, the parasitic portion910is electrically connected to the edge141of the ground element140, and the parasitic portion910faces the first radiation arm121aof the radiation portion121. Furthermore, the first radiation arm121ais disposed between the parasitic portion910and the connecting portion122.FIG. 10describes the diagram showing the return loss of the antenna element inFIG. 9. A return loss curve1010represents a return loss under the condition that the parasitic portion910is not incorporated into the antenna element120; a return loss curve1020represents a return loss under the condition that the parasitic portion910is incorporated into the antenna element120. The return loss curves1010and1020show that the parasitic portion910is configured to increase the bandwidth of the second band (e.g. 5 GHz) of the antenna element120, such that the frequency of the second band ranges from 5.15 GHz to 5.85 GHz.

Based on the above, in the electronic device of the invention, the orthogonal projection of the metal element on the substrate and the orthogonal projection of the antenna element on the substrate are overlapped with each other. Meanwhile, the radiation portion of the antenna element receives the feeding signal via the feeding point, and the connecting portion of the antenna element is electrically connected to the metal element via the first ground point. Furthermore, the radiation portion of the antenna element further has the second ground point that is electrically connected to the metal element. Accordingly, with the arrangement of the second ground point, the effect of metal element on the antenna element can be effectively reduced, thereby facilitating slim design of the electronic device.

Although the invention has been disclosed by the above embodiments, the embodiments are not intended to limit the invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the invention without departing from the scope or spirit of the invention. Therefore, the protecting range of the invention falls in the appended claims.