TWI879021B - Mobile device supporting wideband operation - Google Patents

Abstract

A mobile device supporting wideband operations includes a ground element, a feeding radiation element, a first radiation element, a first switch circuit, a second radiation element, and a second switch circuit. The feeding radiation element has a feeding point. The first radiation element is adjacent to the feeding radiation element. The first switch circuit selectively couples the first radiation element to a first grounding point on the ground element according to a first control voltage. The second radiation element is adjacent to the feeding radiation element. The second switch circuit selectively couples the second radiation element to a second grounding point on the ground element according to a second control voltage. An antenna structure is formed by the ground element, the feeding radiation element, the first radiation element, the first switch circuit, the second radiation element, and the second switch circuit.

Description

Mobile devices that support broadband operation

The present invention relates to a mobile device, and more particularly to a mobile device capable of supporting broadband operation.

With the development of mobile communication technology, mobile devices have become increasingly popular in recent years, such as laptops, mobile phones, multimedia players and other hybrid portable electronic devices. In order to meet people's needs, mobile devices usually have wireless communication functions. Some cover long-distance wireless communication ranges, such as mobile phones using 2G, 3G, LTE (Long Term Evolution) systems and the 700MHz, 850 MHz, 900MHz, 1800MHz, 1900MHz, 2100MHz, 2300MHz and 2500MHz frequency bands used for communication, while some cover short-distance wireless communication ranges, such as Wi-Fi, Bluetooth systems use 2.4GHz, 5.2GHz and 5.8GHz frequency bands for communication.

Antennas are essential components in the field of wireless communications. If the operational bandwidth of an antenna used to receive or transmit signals is too narrow, it will easily cause the communication quality of mobile devices to deteriorate. Therefore, how to design a small-sized, wide-bandwidth antenna structure is an important issue for designers.

In a preferred embodiment, the present invention provides a mobile device supporting broadband operation, comprising: a grounding element; a feed radiation portion having a feed point; a first radiation portion adjacent to the feed radiation portion; a first switching circuit selectively coupling the first radiation portion to a first grounding point on the grounding element according to a first control potential; a second radiation portion adjacent to the feed radiation portion; and a second switching circuit selectively coupling the second radiation portion to a second grounding point on the grounding element according to a second control potential; wherein the grounding element, the feed radiation portion, the first radiation portion, the first switching circuit, the second radiation portion, and the second switching circuit together form an antenna structure.

In some embodiments, the antenna structure operates in one of a first low-frequency mode, a second low-frequency mode, or a high-frequency mode, and the antenna structure can provide different radiation patterns in the first low-frequency mode and the second low-frequency mode.

In some embodiments, the feed radiation portion, the first radiation portion, and the second radiation portion each present a T-shape, and the second radiation portion is substantially symmetrical to the first radiation portion.

In some embodiments, the antenna structure covers a first frequency band, a second frequency band, and a third frequency band, the first frequency band is between 2400 MHz and 2500 MHz, the second frequency band is between 5150 MHz and 5850 MHz, and the third frequency band is between 5925 MHz and 7125 MHz.

In some embodiments, the feed radiation portion includes a first segment, a second segment, and a third segment, wherein the second segment and the third segment are both coupled to the feed point via the first segment.

In some embodiments, the total length of the first segment and the second segment is approximately equal to 0.25 times the wavelength of the third frequency band.

In some embodiments, the first radiation portion includes a fourth segment, a fifth segment, and a sixth segment, wherein the fifth segment and the sixth segment are both coupled to the first switching circuit via the fourth segment.

In some embodiments, the total length of the fourth segment and the sixth segment is approximately equal to 0.25 times the wavelength of the first frequency band, and the total length of the fifth segment and the sixth segment is approximately equal to 0.5 times the wavelength of the second frequency band.

In some embodiments, the first switching circuit includes: a first diode having an anode and a cathode, wherein the anode of the first diode is coupled to a first connection point on the first radiation portion, and the cathode of the first diode is coupled to the first ground point; and a first inductor having a first end and a second end, wherein the first end of the first inductor is coupled to the first connection point, and the second end of the first inductor is used to receive the first control potential.

In some embodiments, the second switching circuit includes: a second diode having an anode and a cathode, wherein the anode of the second diode is coupled to a second connection point on the second radiation portion, and the cathode of the second diode is coupled to the second ground point; and a second inductor having a first end and a second end, wherein the first end of the second inductor is coupled to the second connection point, and the second end of the second inductor is used to receive the second control potential.

In order to make the purpose, features and advantages of the present invention more clearly understood, specific embodiments of the present invention are specifically listed below and described in detail with reference to the accompanying drawings.

Certain terms are used in the specification and patent application to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and patent application do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criterion for distinction. The words "include" and "including" mentioned throughout the specification and patent application are open terms and should be interpreted as "including but not limited to". The word "substantially" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and achieve the basic technical effect. In addition, the word "coupled" in this specification includes any direct and indirect electrical connection means. Therefore, if a first device is described herein as being coupled to a second device, it means that the first device may be directly electrically connected to the second device, or may be indirectly electrically connected to the second device via other devices or connection means.

The following disclosure provides many different embodiments or examples for implementing different features of the present invention. The following disclosure describes specific examples of various components and their arrangements to simplify the description. Of course, these specific examples are not intended to be limiting. For example, if the present disclosure describes a first feature formed on or above a second feature, it means that it may include an embodiment in which the first feature and the second feature are in direct contact, and may also include an embodiment in which an additional feature is formed between the first feature and the second feature, so that the first feature and the second feature may not be in direct contact. In addition, the same reference symbols and/or marks may be reused in different examples of the following disclosure. These repetitions are for the purpose of simplification and clarity, and are not intended to limit the specific relationship between the different embodiments and/or structures discussed.

In addition, spatially related terms such as "below," "below," "lower," "above," "higher," and similar terms are used to facilitate description of the relationship between one element or feature and another element or features in the diagram. In addition to the orientation shown in the drawings, these spatially related terms are intended to include different orientations of the device in use or operation. The device may be rotated to different orientations (rotated 90 degrees or other orientations), and the spatially related terms used herein may be interpreted accordingly.

FIG. 1 is a schematic diagram showing a mobile device 100 according to an embodiment of the present invention. For example, the mobile device 100 may be a smart phone, a tablet computer, or a notebook computer. In the embodiment of FIG. 1 , the mobile device 100 includes a ground element 110, a feeding radiation element 120, a first radiation element 130, a first switching circuit 140, a second radiation element 150, and a second switching circuit 160, wherein the ground element 110, the feeding radiation element 120, the first radiation element 130, and the second radiation element 150 can all be made of metal materials, such as copper, silver, aluminum, iron, or alloys thereof. It should be understood that, although not shown in FIG. 1 , the mobile device 100 may further include other components, such as a processor, a touch control panel, a speaker, a power supply module, or (and) a housing.

The grounding element 110 may be implemented by a ground copper foil, which may be used to provide a ground voltage VSS. For example, the grounding element 110 may be regarded as a system ground plane of the mobile device 100, but is not limited thereto.

The feeding radiation part 120 may be substantially T-shaped. Specifically, the feeding radiation part 120 has a first end 121, a second end 122, and a third end 123, wherein a feeding point FP is located at the first end 121 of the feeding radiation part 120, and the second end 122 and the third end 123 of the feeding radiation part 120 may each be an open end. The feeding point FP may be further coupled to a signal source 190. For example, the signal source 190 may be a radio frequency (RF) module. In some embodiments, the feed radiation portion 120 includes a first segment 124 adjacent to the first end 121, a second segment 125 adjacent to the second end 122, and a third segment 126 adjacent to the third end 123, wherein the second segment 125 and the third segment 126 can be coupled to the feed point FP via the first segment 124. It should be noted that the term "adjacent" or "adjacent" in this specification may refer to a distance between two corresponding elements being less than a predetermined distance (e.g., 10 mm or shorter), and may also include a situation where two corresponding elements are in direct contact with each other (i.e., the aforementioned distance is shortened to 0).

The first radiating portion 130 may be roughly in another T-shape. Specifically, the first radiating portion 130 has a first end 131, a second end 132, and a third end 133, wherein a first connection point CP1 is located at the first end 131 of the first radiating portion 130, and the second end 132 and the third end 133 of the first radiating portion 130 may each be an open end. The first connection point CP1 may be further coupled to the first switching circuit 140. In some embodiments, the first radiation portion 130 includes a fourth segment 134 adjacent to the first end 131, a fifth segment 135 adjacent to the second end 132, and a sixth segment 136 adjacent to the third end 133, wherein the fifth segment 135 and the sixth segment 136 can be coupled to the first connection point CP1 and the first switching circuit 140 via the fourth segment 134. In some embodiments, the first radiation portion 130 is adjacent to the feed radiation portion 120, so that a first coupling gap GC1 can be formed between the sixth segment 136 and the second segment 125.

The internal circuit structure of the first switching circuit 140 is not particularly limited in the present invention. Generally speaking, the first switching circuit 140 can selectively couple the first connection point CP1 of the first radiating portion 130 to a first ground point GP1 on the ground element 110 according to a first control potential VC1. For example, if the first control potential VC1 is a high logic level (i.e., logic "1"), the first switching circuit 140 can couple the first connection point CP1 to the first ground point GP1 (i.e., the first switching circuit 140 can be approximated as a short circuit path); conversely, if the first control potential VC1 is a low logic level (i.e., logic "0"), the first switching circuit 140 will not couple the first connection point CP1 to the first ground point GP1 (i.e., the first switching circuit 140 can be approximated as an open circuit path).

The second radiation portion 150 may be substantially in another T-shape, wherein the second radiation portion 150 may be substantially symmetrical with the second radiation portion 130. Specifically, the second radiation portion 150 has a first end 151, a second end 152, and a third end 153, wherein a second connection point CP2 is located at the first end 151 of the second radiation portion 150, and the second end 152 and the third end 153 of the second radiation portion 150 may each be an open end. The second connection point CP2 may be further coupled to the second switching circuit 160. In some embodiments, the second radiation portion 150 includes a seventh segment 154 adjacent to the first end 151, an eighth segment 155 adjacent to the second end 152, and a ninth segment 156 adjacent to the third end 153, wherein the eighth segment 155 and the ninth segment 156 can be coupled to the second connection point CP2 and the second switching circuit 160 via the seventh segment 154. In some embodiments, the second radiation portion 150 is adjacent to the feed radiation portion 120, so that a second coupling gap GC2 can be formed between the ninth segment 156 and the third segment 126.

The internal circuit structure of the second switching circuit 160 is not particularly limited in the present invention. Generally speaking, the second switching circuit 160 can selectively couple the second connection point CP2 of the second radiating portion 150 to a second grounding point GP2 on the grounding element 110 according to a second control potential VC2, wherein the second grounding point GP2 can be different from the aforementioned first grounding point GP1. For example, if the second control potential VC2 is a high logic level, the second switching circuit 160 can couple the second connection point CP2 to the second ground point GP2 (that is, the second switching circuit 160 can be approximated as a short circuit path); conversely, if the second control potential VC2 is a low logic level, the second switching circuit 160 will not couple the second connection point CP2 to the second ground point GP2 (that is, the second switching circuit 160 can be approximated as an open circuit path).

In a preferred embodiment, the grounding element 110, the feed radiation part 120, the first radiation part 130, the first switching circuit 140, the second radiation part 150, and the second switching circuit 160 can together form an antenna structure (Antenna Structure) of the mobile device 100. The antenna structure of the mobile device 100 can be disposed on a dielectric substrate (Dielectric Substrate) (not shown). For example, the aforementioned dielectric substrate can be a FR4 (Flame Retardant 4) substrate, a printed circuit board (Printed Circuit Board, PCB), or a flexible circuit board (Flexible Printed Circuit, FPC), but it is not limited thereto. Under the design of the present invention, the antenna structure of the mobile device 100 can provide a variable operating frequency and a tunable radiation pattern to adapt to various usage environments.

The following embodiments will introduce the detailed structure and operation of the mobile device 100. It must be understood that these drawings and descriptions are only examples and are not intended to limit the scope of the present invention.

FIG. 2 is a circuit diagram of a first switching circuit 140 according to an embodiment of the present invention. In the embodiment of FIG. 2, the first switching circuit 140 includes a first diode D1 and a first inductor LA. For example, the first diode D1 may be a positive negative diode (PIN diode), but is not limited thereto. The first diode D1 has an anode and a cathode, wherein the anode of the first diode D1 is coupled to the first connection point CP1, and the cathode of the first diode D1 is coupled to the first ground point GP1. The first inductor LA has a first end and a second end, wherein the first end of the first inductor LA is coupled to the first connection point CP1, and the second end of the first inductor LA is used to receive the first control potential VC1. If the first control potential VC1 is a high logic level, the first diode D1 will be turned on, and if the first control potential VC1 is a low logic level, the first diode D1 will be turned off. In addition, the first inductor LA can also be used to filter high-frequency noise related to the first control potential VC1.

FIG. 3 is a circuit diagram showing a second switching circuit 160 according to an embodiment of the present invention. In the embodiment of FIG. 3, the second switching circuit 160 includes a second diode D2 and a second inductor LB. For example, the second diode D2 may be another positive-negative diode, but is not limited thereto. The second diode D2 has an anode and a cathode, wherein the anode of the second diode D2 is coupled to the second connection point CP2, and the cathode of the second diode D2 is coupled to the second ground point GP2. The second inductor LB has a first end and a second end, wherein the first end of the second inductor LB is coupled to the second connection point CP2, and the second end of the second inductor LB is used to receive the second control potential VC2. If the second control potential VC2 is at a high logic level, the second diode D2 will be turned on, and if the second control potential VC2 is at a low logic level, the second diode D2 will be turned off. In addition, the second inductor LB can also be used to filter out high-frequency noise related to the second control potential VC2.

In some embodiments, the first control potential VC1 and the second control potential VC2 may be generated by a controller (not shown) according to a user input or a processor command. In response to different levels of the first control potential VC1 and the second control potential VC2, the antenna structure of the mobile device 100 may be operated in a first low frequency mode, a second low frequency mode, or a high frequency mode. For example, the relationship between the aforementioned operating modes and control potentials may be described in Table 1 below: The first control potential VC1 The second control potential VC2 First low frequency mode Low logic level (0) High logic level (1) Second low frequency mode High logic level (1) Low logic level (0) High frequency mode Low logic level (0) Low logic level (0) Table 1: Relationship between antenna structure operation mode and control potential

FIG. 4 shows a return loss diagram of the antenna structure of the mobile device 100 in the first low frequency mode according to an embodiment of the present invention, wherein the horizontal axis represents the operating frequency (MHz) and the vertical axis represents the return loss (dB). According to the measurement results of FIG. 4, when the first control potential VC1 is a low logic level and the second control potential VC2 is a high logic level, the antenna structure of the mobile device 100 will cover a first frequency band FB1 and a second frequency band FB2. For example, the first frequency band FB1 may be between 2400MHz and 2500MHz, and the second frequency band FB2 may be between 5150MHz and 5850MHz.

FIG. 5 is a graph showing the return loss of the antenna structure of the mobile device 100 in the second low frequency mode according to an embodiment of the present invention, wherein the horizontal axis represents the operating frequency (MHz) and the vertical axis represents the return loss (dB). According to the measurement results of FIG. 5, when the first control potential VC1 is a high logic level and the second control potential VC2 is a low logic level, the antenna structure of the mobile device 100 can also cover the aforementioned first frequency band FB1 and a second frequency band FB2. It should be noted that the antenna structure of the mobile device 100 can provide different radiation patterns in the first low frequency mode and the second low frequency mode.

FIG6 is a graph showing the return loss of the antenna structure of the mobile device 100 in the high-frequency mode according to an embodiment of the present invention, wherein the horizontal axis represents the operating frequency (MHz) and the vertical axis represents the return loss (dB). According to the measurement results of FIG6, when both the first control potential VC1 and the second control potential VC2 are at a low logic level, the antenna structure of the mobile device 100 will be able to cover a third frequency band FB3. For example, the third frequency band FB3 may be between 5925 MHz and 7125 MHz. Therefore, by appropriately adjusting the first control potential VC1 and the second control potential VC2, the mobile device 100 will at least be able to support the broadband operation of the traditional WLAN (Wireless Local Area Network) and the new generation Wi-Fi 6E.

FIG. 7 shows a radiation pattern of the antenna structure of the mobile device 100 in the first low-frequency mode according to an embodiment of the present invention, which can be measured along the XY plane. According to the measurement result of FIG. 7, when the first control potential VC1 is a low logic level and the second control potential VC2 is a high logic level, the antenna structure of the mobile device 100 can be operated in the first low-frequency mode, and its maximum radiation direction in the first frequency band FB1 will be toward the -X axis.

FIG. 8 shows the radiation pattern of the antenna structure of the mobile device 100 in the second low frequency mode according to an embodiment of the present invention, which can be measured along the XY plane. According to the measurement result of FIG. 8, when the first control potential VC1 is at a high logic level and the second control potential VC2 is at a low logic level, the antenna structure of the mobile device 100 can operate in the second low frequency mode, and its maximum radiation direction in the first frequency band FB1 will be toward the +X axis. Under this design, the antenna structure of the mobile device 100 will be able to easily receive or transmit electromagnetic waves in various directions.

In some embodiments, the component sizes and component parameters of the mobile device 100 may be as follows: In the feed radiation portion 120, the total length L1 of the first section 124 and the second section 125 may be substantially equal to 0.25 times the wavelength (λ/4) of the third frequency band FB3 of the antenna structure of the mobile device 100, and the total length L4 of the first section 124 and the third section 126 may also be substantially equal to 0.25 times the wavelength (λ/4) of the third frequency band FB3 of the antenna structure of the mobile device 100. In the first radiating portion 130, the total length L2 of the fourth section 134 and the sixth section 136 may be substantially equal to 0.25 times the wavelength (λ/4) of the first frequency band FB1 of the antenna structure of the mobile device 100, and the total length L3 of the fifth section 135 and the sixth section 136 may be substantially equal to 0.5 times the wavelength (λ/2) of the second frequency band FB2 of the antenna structure of the mobile device 100. The width of the first coupling gap GC1 may be between 1 mm and 1.5 mm. In the second radiating portion 150, the total length L5 of the seventh section 154 and the ninth section 156 may be approximately equal to 0.25 times the wavelength (λ/4) of the first frequency band FB1 of the antenna structure of the mobile device 100, and the total length L6 of the eighth section 155 and the ninth section 156 may be approximately equal to 0.5 times the wavelength (λ/2) of the second frequency band FB2 of the antenna structure of the mobile device 100. The width of the second coupling gap GC2 may be between 1 mm and 1.5 mm. The shortest distance DS between the first radiating portion 130 and the second radiating portion 150 may be between 1 mm and 2 mm. The inductance of the first inductor LA may be greater than or equal to 8.2 nH. The inductance of the second inductor LB may also be greater than or equal to 8.2 nH. The above ranges of component sizes and component parameters are obtained based on multiple experimental results, which are helpful in optimizing the operational bandwidth and impedance matching of the antenna structure of the mobile device 100.

The present invention proposes a novel mobile device and antenna structure thereof. Compared with the traditional design, the present invention has at least the advantages of variable operating frequency, adjustable radiation pattern, and low manufacturing cost, so it is very suitable for application in various types of devices.

It is worth noting that the above-mentioned component size, component shape, component parameters, and frequency range are not limiting conditions of the present invention. Antenna designers can adjust these settings according to different needs. The mobile device of the present invention is not limited to the states shown in Figures 1-8. The present invention may include only one or more features of any one or more embodiments of Figures 1-8. In other words, not all the features shown in the diagrams need to be implemented in the mobile device of the present invention at the same time.

Ordinal numbers in this specification and the scope of the patent application, such as "first", "second", "third", etc., have no sequential relationship with each other, and are only used to mark and distinguish two different components with the same name.

Although the present invention is disclosed as above with the preferred embodiments, it is not intended to limit the scope of the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the attached patent application.

100: mobile device 110: grounding element 120: feeding radiation part 121: first end of feeding radiation part 122: second end of feeding radiation part 123: third end of feeding radiation part 124: first section 125: second section 126: third section 130: first radiation part 131: first end of first radiation part 132: second end of first radiation part 133: third end of first radiation part 134: fourth section 135: fifth section 136: sixth section 140: first switching circuit 150: second radiation part 151: first end of second radiation part 152: Second end of the second radiation part 153: Third end of the second radiation part 154: Seventh segment 155: Eighth segment 156: Ninth segment 160: Second switching circuit 190: Signal source CP1: First connection point CP2: Second connection point D1: First diode D2: Second diode DS: Spacing FB1: First frequency band FB2: Second frequency band FB3: Third frequency band FP: Feed point GC1: First coupling gap GC2: Second coupling gap GP1: First ground point GP2: Second ground point L1, L2, L3, L4, L5, L6: Length LA: First inductor LB: Second inductor VC1: First control potential VC2: Second control potential VSS: Ground potential X: X axis Y: Y axis Z: Z axis

FIG. 1 is a schematic diagram showing a mobile device according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a first switching circuit according to an embodiment of the present invention. FIG. 3 is a circuit diagram showing a second switching circuit according to an embodiment of the present invention. FIG. 4 is a return loss diagram showing an antenna structure of a mobile device according to an embodiment of the present invention in a first low-frequency mode. FIG. 5 is a return loss diagram showing an antenna structure of a mobile device according to an embodiment of the present invention in a second low-frequency mode. FIG. 6 is a return loss diagram showing an antenna structure of a mobile device according to an embodiment of the present invention in a high-frequency mode. FIG. 7 shows the radiation pattern of the antenna structure of the mobile device according to an embodiment of the present invention in the first low-frequency mode. FIG. 8 shows the radiation pattern of the antenna structure of the mobile device according to an embodiment of the present invention in the second low-frequency mode.

100: Mobile devices

110: Grounding element

120: Feed Radiation Department

121: Feeding the first end of the radiation unit

122: Feed the second end of the radiation unit

123: The third end of the feed radiation unit

124: Section 1

125: Second section

126: The third section

130: First Radiation Division

131: The first end of the first radiation section

132: The second end of the first radiation section

133: The third end of the first radiation section

134: Section 4

135: Section 5

136: Section 6

140: First switching circuit

150: Second Radiation Division

151: The first end of the second radiation section

152: The second end of the second radiation section

153: The third end of the second radiation section

154: Section 7

155: Section 8

156: Section 9

160: Second switching circuit

190:Signal source

CP1: First connection point

CP2: Second connection point

DS: Spacing

FP: Feed Point

GC1: First coupling gap

GC2: Second coupling gap

GP1: First grounding point

GP2: Second grounding point

L1,L2,L3,L4,L5,L6: Length

VC1: first control potential

VC2: Second control potential

VSS: ground potential

X: X axis

Y:Y axis

Z:Z axis

Claims (9)

A mobile device supporting broadband operation includes: a grounding element; a feeding radiation part having a feeding point; a first radiation part adjacent to the feeding radiation part; a first switching circuit selectively coupling the first radiation part to a first grounding point on the grounding element according to a first control potential; a second radiation part adjacent to the feeding radiation part; and a second switching circuit selectively coupling the second radiation part to a first grounding point on the grounding element according to a second control potential. The first radiating portion is coupled to a second grounding point on the grounding element; wherein the grounding element, the feed radiating portion, the first radiating portion, the first switching circuit, the second radiating portion, and the second switching circuit together form an antenna structure; wherein the antenna structure operates in a first low-frequency mode, a second low-frequency mode, or a high-frequency mode, and the antenna structure can provide different radiation field patterns in the first low-frequency mode and the second low-frequency mode. As in claim 1, the mobile device, wherein the feed radiation portion, the first radiation portion, and the second radiation portion each present a T-shape, and the second radiation portion is substantially symmetrical to the first radiation portion. A mobile device as claimed in claim 1, wherein the antenna structure covers a first frequency band, a second frequency band, and a third frequency band, the first frequency band is between 2400 MHz and 2500 MHz, the second frequency band is between 5150 MHz and 5850 MHz, and the third frequency band is between 5925 MHz and 7125 MHz. A mobile device as claimed in claim 3, wherein the feed radiation portion includes a first section, a second section, and a third section, wherein the second section and the third section are both coupled to the feed point via the first section. A mobile device as claimed in claim 4, wherein the total length of the first segment and the second segment is approximately equal to 0.25 times the wavelength of the third frequency band. A mobile device as claimed in claim 3, wherein the first radiation section includes a fourth section, a fifth section, and a sixth section, wherein the fifth section and the sixth section are both coupled to the first switching circuit via the fourth section. A mobile device as claimed in claim 6, wherein the total length of the fourth segment and the sixth segment is approximately equal to 0.25 times the wavelength of the first frequency band, and the total length of the fifth segment and the sixth segment is approximately equal to 0.5 times the wavelength of the second frequency band. A mobile device as claimed in claim 1, wherein the first switching circuit comprises: a first diode having an anode and a cathode, wherein the anode of the first diode is coupled to a first connection point on the first radiation portion, and the cathode of the first diode is coupled to the first ground point; and a first inductor having a first end and a second end, wherein the first end of the first inductor is coupled to the first connection point, and the second end of the first inductor is used to receive the first control potential. A mobile device as claimed in claim 1, wherein the second switching circuit comprises: a second diode having an anode and a cathode, wherein the anode of the second diode is coupled to a second connection point on the second radiation portion, and the cathode of the second diode is coupled to the second ground point; and a second inductor having a first end and a second end, wherein the first end of the second inductor is coupled to the second connection point, and the second end of the second inductor is used to receive the second control potential.

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