Electronic device

1. An electronic device, comprising:

a ground plane;

a metal frame, having a plurality of gaps to form a frame element, wherein a first end of the frame element is electrically connected to the ground plane, and a second end of the frame element is an open end;

a plurality of radiation elements, enclosed by the frame element, and each of the radiation elements being spaced by a coupling distance from the frame element; and

a switching circuit, selecting one of the radiation elements to transmit a feeding signal,

wherein when the feeding signal is transmitted to a first radiation element among the radiation elements, the electronic device operates in a first band through the first radiation element, and operates in a second band through the frame element, and

when the feeding signal is transmitted to a second radiation element among the radiation elements, the electronic device operates in a third band through the second radiation element and operates in a fourth band through the frame element.

2. The electronic device as claimed in claim 1 , further comprising:

an appearance member, forming an accommodating space together with the metal frame, wherein the ground plane, the radiation elements and the switching circuit are disposed in the accommodating space, and an orthogonal projection of the radiation elements on the appearance member is not overlapped with an orthogonal projection of the ground plane on the appearance member.

3. The electronic device as claimed in claim 2 , wherein the appearance member is a plastic back cover, and the radiation elements and the ground plane are attached to the plastic back cover.

4. The electronic device as claimed in claim 2 , wherein the appearance member is a metal back cover, and the metal back cover is electrically connected to the ground plane.

5. The electronic device as claimed in claim 2 , further comprising:

a transceiver, disposed in the accommodating space, and generating the feeding signal, wherein the switching circuit has a first connecting end and a plurality of second connecting ends, the first connecting end is electrically connected to the transceiver, and the second connecting ends are electrically connected to the radiation elements, and the switching circuit connects the first connecting end to one of the second connecting ends according to a control signal.

6. The electronic device as claimed in claim 2 , further comprising:

an inductive element, disposed in the accommodating space, wherein the first end of the frame element is electrically connected to the ground plane through the inductive element.

7. The electronic device as claimed in claim 1 , wherein a shape of the frame element is a U-shape.

8. The electronic device as claimed in claim 1 , wherein a first edge of the first radiation element is spaced by the coupling distance from the frame element, a second edge of the second radiation element is spaced by the coupling distance from the frame element, and a length of the first edge is greater than a length of the second edge, such that a frequency of the second band is lower than a frequency of the fourth band.

9. The electronic device as claimed in claim 8 , wherein a frequency of the third band is higher than a frequency of the first band, and the frequency of the first bend is higher than the frequency of the fourth band.

10. The electronic device as claimed in claim 1 , wherein the radiation elements are respectively a monopole antenna, a planar inverted F antenna, a dipole antenna or a loop antenna.