CN111326858B

CN111326858B - Antenna structure

Info

Publication number: CN111326858B
Application number: CN201811541098.6A
Authority: CN
Inventors: 陈威辰; 张政伟
Original assignee: Wistron Neweb Corp
Current assignee: Wistron Neweb Corp
Priority date: 2018-12-17
Filing date: 2018-12-17
Publication date: 2021-09-03
Anticipated expiration: 2038-12-17
Also published as: CN111326858A

Abstract

The invention discloses an antenna structure, comprising: a metal machine component, a grounding element, a feed-in radiation part, a coupling part, a medium substrate and a switching circuit. The metal machine component has a slot. The feed-in radiation part extends across the slot. A coupling gap is formed between the feed radiation part and the coupling part. The feed-in radiation part and the coupling part are arranged on the medium substrate. The switching circuit includes a first metal portion, a second metal portion, a reactance element, a capacitor, and a diode. The first metal portion is coupled to the coupling portion. The reactance element is embedded in the first metal part. The second metal portion is coupled to the grounding element through the capacitor. The diode is coupled between the first metal part and the second metal part, wherein the diode is selectively conducted or not conducted according to a control voltage.

Description

Antenna structure

Technical Field

The present invention relates to an Antenna Structure, and more particularly, to a Wideband (Wideband) Antenna Structure.

Background

With the development of mobile communication technology, mobile devices have become increasingly popular in recent years, such as: portable computers, mobile phones, multimedia players and other portable electronic devices with mixed functions. To meet the demand of people, mobile devices usually have wireless communication functions. Some cover long-distance wireless communication ranges, such as: the mobile phone uses 2G, 3G, LTE (Long Term Evolution) system and its used frequency bands of 700MHz, 850MHz, 900MHz, 1800MHz, 1900MHz, 2100MHz, 2300MHz and 2500MHz for communication, while some cover short-distance wireless communication ranges, for example: Wi-Fi and Bluetooth systems use 2.4GHz, 5.2GHz and 5.8GHz frequency bands for communication.

In order to pursue the aesthetic appearance, designers nowadays often add elements of metal components to mobile devices. However, the added metal elements tend to adversely affect the antenna supporting wireless communication in the mobile device, thereby reducing the overall communication quality of the mobile device. Therefore, there is a need for a new mobile device and antenna structure to overcome the problems encountered in the conventional technology.

Disclosure of Invention

In a preferred embodiment, the present invention provides an antenna structure comprising: a metal machine component having a slot; a grounding element coupled to the metal machine component; a feed-in radiation part coupled to a signal source, wherein the feed-in radiation part extends across the slot; a coupling part adjacent to the feed-in radiation part, wherein a coupling gap is formed between the feed-in radiation part and the coupling part; a dielectric substrate, wherein the feed-in radiation part and the coupling part are both arranged on the dielectric substrate; and a switching circuit, comprising: a first metal portion coupled to the coupling portion; a reactance element embedded in the first metal part; a second metal portion; a capacitor, wherein the second metal portion is coupled to the ground element via the capacitor; and a diode coupled between the first metal part and the second metal part, wherein the diode is selectively conducted or not conducted according to a control voltage.

In some embodiments, the metal machine component is a metal back cover of a mobile device.

In some embodiments, the slot is a closed slot having a first closed end and a second closed end.

In some embodiments, the grounding element is a grounding copper foil and extends from the metal frame member to the dielectric substrate.

In some embodiments, the feeding radiating part is in a straight strip shape.

In some embodiments, the feeding radiating part has a non-uniform width structure.

In some embodiments, the feed radiation portion includes a narrow portion and a wide portion, the wide portion having a vertical projection on the metal machine component, the vertical projection at least partially overlapping the slot.

In some embodiments, the feeding radiating element further comprises a first protruding portion coupled to a positive pole of the signal source, the grounding element further comprises a second protruding portion coupled to a negative pole of the signal source.

In some embodiments, the first protruding portion of the feed radiating portion is coupled to the narrower portion of the feed radiating portion.

In some embodiments, the coupling portion has a serpentine configuration.

In some embodiments, the diode has an anode coupled to the first metal portion and a cathode coupled to the second metal portion.

In some embodiments, the first metal portion and the second metal portion each present a straight strip shape.

In some embodiments, the first metal portion and the second metal portion are for receiving the control voltage.

In some embodiments, when the control voltage is decreased, the diode is not turned on and the antenna structure covers a first frequency interval, and when the control voltage is increased, the diode is turned on and the antenna structure covers a second frequency interval higher than the first frequency interval.

In some embodiments, the antenna structure has an operating frequency band between 2400MHz and 2500MHz, or (and) between 5150MHz and 5850 MHz.

In some embodiments, the length of the slot is equal to 0.5 wavelengths of the lowest frequency of the operating band.

In some embodiments, the length of the feed radiating portion is equal to 0.25 wavelengths of the lowest frequency of the operating band.

In some embodiments, the length of the coupling portion is equal to 0.25 wavelengths of the lowest frequency of the operating band.

In another preferred embodiment, the present invention provides an antenna structure comprising: a metal machine component having a slot; a grounding element coupled to the metal machine component; a feed-in radiation part coupled to a signal source, wherein the feed-in radiation part extends across the slot; a coupling part adjacent to the feed-in radiation part, wherein a coupling gap is formed between the feed-in radiation part and the coupling part; a dielectric substrate, wherein the feed-in radiation part and the coupling part are both arranged on the dielectric substrate; and a switching circuit, comprising: a first metal portion coupled to the coupling portion; a first resistor embedded in the first metal part; a second metal portion; a second resistor embedded in the second metal part; and a bipolar junction transistor operating according to a control voltage, wherein the bipolar junction transistor has an emitter coupled to the ground element, a base coupled to the second metal portion, and a collector coupled to the first metal portion.

In another preferred embodiment, the present invention provides a mobile device comprising: a metal machine component having a slot; a grounding element coupled to the metal machine component; a feed-in radiation part coupled to a signal source, wherein the feed-in radiation part extends across the slot; a coupling part adjacent to the feed-in radiation part, wherein a coupling gap is formed between the feed-in radiation part and the coupling part; a dielectric substrate, wherein the feed-in radiation part and the coupling part are both arranged on the dielectric substrate; and a switching circuit, comprising: a first metal portion coupled to the coupling portion; an inductor embedded in the first metal part; a second metal portion; a capacitor, wherein the second metal portion is coupled to the ground element via the capacitor; and a diode coupled between the first metal part and the second metal part, wherein the diode is selectively conducted or not conducted according to a control voltage; wherein the metal machine component, the grounding element, the feed-in radiation part, the coupling part, the dielectric substrate and the switching circuit together form an antenna structure.

Drawings

Fig. 1A is a top view of an antenna structure according to an embodiment of the invention;

fig. 1B is a cross-sectional view of an antenna structure according to an embodiment of the invention;

fig. 2A is a voltage standing wave ratio diagram of an antenna structure according to an embodiment of the invention;

fig. 2B is a voltage standing wave ratio diagram of an antenna structure according to another embodiment of the present invention;

fig. 3 is a radiation efficiency diagram of an antenna structure according to an embodiment of the present invention;

fig. 4 is a top view of an antenna structure according to another embodiment of the present invention;

fig. 5 is a top view of an antenna structure according to another embodiment of the present invention;

fig. 6 is a top view of an antenna structure according to another embodiment of the present invention;

fig. 7 is a schematic diagram of a mobile device according to an embodiment of the invention.

Description of the symbols

100. 400, 500, 600, 750-antenna structure;

110-metal machine components;

120-slotted hole;

121-a first closed end of the slot;

122 to the second closed end of the slot;

130-a grounding element;

135-a second protruding portion of the grounding element;

140-feeding radiation part;

141-a first end of the feed-in radiation part;

142-a second end of the feed-in radiation part;

143-the narrower part of the feed radiating section;

144-the wider part of the feed-in radiating part;

145-first protruding part fed into the radiating part;

150. 450-a coupling part;

151. 451 to the first end of the coupling part;

152. 452 to the second end of the coupling part;

160-dielectric substrate;

170. 570, 670-switching circuit;

180. 580, 680 to a first metal portion;

181. 681 to a first portion of the first metal part;

182. 682-a second portion of the first metal part;

185-a reactive element;

190. 590, 690 to a second metal part;

650-bipolar junction transistor;

691 to a first portion of the second metal part;

692 to a second portion of the second metal portion;

199-signal source;

700-a mobile device;

c, a capacitor;

CC1 — first curve;

CC 2-second curve;

d, a diode;

e1-the first surface of the dielectric substrate;

e2-the second surface of the dielectric substrate;

FP-feed point;

FV 1-first frequency interval;

FV 2-second frequency interval;

GC 1-coupling gap;

GP to a ground point;

l-an inductor;

l1, L2, L3, L4, L5-length;

LC 1-section line;

r1-first resistor;

r2-second resistor;

VD-control voltage;

w1, W2-width.

Detailed Description

In order to make the objects, features and advantages of the present invention comprehensible, specific embodiments accompanied with figures are described in detail below.

Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. The present specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The term "substantially" refers to a range of acceptable error within which one skilled in the art can solve the technical problem to achieve the basic technical result. In addition, the term "coupled" is used herein to encompass any direct or indirect electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.

Fig. 1A shows a top view of an antenna structure 100 according to an embodiment of the invention. Fig. 1B shows a cross-sectional view (along a section line LC1 in fig. 1A) of the antenna structure 100 according to an embodiment of the invention. Please refer to fig. 1A and fig. 1B together. The antenna structure 100 can be applied to a Mobile Device (Mobile Device), for example: a Smart Phone (Smart Phone), a Tablet Computer (Tablet Computer), or a Notebook Computer (Notebook Computer). In the embodiment of fig. 1A, 1B, the antenna structure 100 includes at least: a Metal mechanical Element (Metal mechanical Element)110, a Ground Element (Ground Element)130, a Feeding Radiation Element (Feeding Radiation Element)140, a Coupling Element (Coupling Element)150, a Dielectric Substrate (Dielectric Substrate)160, and a switching Circuit (switching Circuit)170, wherein the Ground Element 130, the Feeding Radiation Element 140, and the Coupling Element 150 are made of Metal materials, such as: copper, silver, aluminum, iron, or alloys thereof.

The Metal machine component 110 may be a Metal Housing (Metal Housing) of the mobile device. In some embodiments, the Metal machine component 110 is a Metal Upper Cover (Metal Upper Cover) of a notebook computer or a Metal Back Cover (Metal Back Cover) of a tablet computer, but is not limited thereto. The metal machine component 110 has a slot 120, wherein the slot 120 of the metal machine component 110 may be substantially in the shape of a straight strip. In detail, the Slot 120 belongs to a Closed Slot (Closed Slot) having a first Closed End (Closed End)121 and a second Closed End 122 which are far away from each other. The antenna structure 100 may further include a non-conductive material filled in the slot 120 of the metal machine component 110.

The dielectric substrate 160 may be an FR4 (film resistor 4) substrate, a Printed Circuit Board (PCB), or a Flexible Circuit Board (FCB). The dielectric substrate 160 has a first surface E1 and a second surface E2 opposite to each other, wherein the feeding radiating element 140 and the coupling element 150 are disposed on the first surface E1 of the dielectric substrate 160, and the second surface E2 of the dielectric substrate 160 is adjacent to the slot 120 of the metal machine component 110. 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., 5mm or less), and may also include the case where two corresponding elements are in direct contact with each other (i.e., the distance is reduced to 0). In some embodiments, the second surface E2 of the dielectric substrate 160 is attached to the metal machine member 110, wherein the dielectric substrate 160 extends across the slot 120 of the metal machine member 110. The Ground plane 130 may be a Ground Copper Foil (Ground Copper Foil), which may be stepped (as shown in fig. 1B). For example, the ground plane 130 may be coupled to the metal machine member 110 and extend from the metal machine member 110 to the first surface E1 of the dielectric substrate 160.

The feeding radiating part 140 may be substantially in the shape of a straight bar. The Feeding radiating portion 140 has a Feeding Point (FP), which can be coupled to a Signal Source (Signal Source) 199. For example, the signal source 199 can be a Radio Frequency (RF) module, and the feeding radiating portion 140 can extend across the slot 120 of the metal machine element 110 to excite the antenna structure 100. The feeding radiating portion 140 has a first End 141 and a second End 142 that are far away from each other, wherein the first End 141 and the second End 142 of the feeding portion 140 are two Open ends (Open ends). In some embodiments, the feeding radiating portion 140 has a non-uniform width structure. For example, the feeding radiating part 140 may include a narrow portion 143 and a wide portion 144, wherein the narrow portion 143 is adjacent to the first end 141 of the feeding radiating part 140, and the wide portion 144 is adjacent to the second end 142 of the feeding radiating part 140. In detail, the wider portion 144 of the feeding radiation part 140 has a Vertical Projection (Vertical Projection) on the metal machine component 110, wherein the Vertical Projection at least partially overlaps with the slot 120. In addition, the narrow portion 143 of the feeding radiation part 140 has a vertical projection on the metal machine component 110, wherein the vertical projection may partially overlap with the slot 120 or may not overlap with the slot 120 at all. In some embodiments, the feeding radiating portion 140 further includes a first protruding portion 145 coupled to the narrower portion 143, and the grounding element 130 further includes a second protruding portion 135, wherein the first protruding portion 145 and the second protruding portion 135 may extend in a direction substantially approaching each other. The first projection 145 and the second projection 135 may each generally exhibit a rectangular or a square shape. In some embodiments, the feeding Point FP is located on the first protrusion 145 of the feeding radiating portion 140 and coupled to a Positive Electrode (Positive Electrode) of the signal source 199, and a Grounding Point GP is located on the second protrusion 135 of the Grounding element 130 and coupled to a Negative Electrode (Negative Electrode) of the signal source 199. It should be noted that the first protruding portion 145 and the second protruding portion 135 are Optional elements (Optional elements), and may be removed in other embodiments.

The coupling portion 150 may have a Meandering Structure. For example, the coupling portion 150 may substantially have a W-shape, but is not limited thereto. The Coupling portion 150 is adjacent to the feeding radiating portion 140, wherein a Coupling Gap (Coupling Gap) GC1 can be formed between the wider portion 144 of the feeding radiating portion 140 and the Coupling portion 150. In detail, the coupling portion 150 has a first end 151 and a second end 152, wherein the first end 151 of the coupling portion 150 is coupled to the switching circuit 170, and the second end 152 of the coupling portion 150 is an open end, which can extend between the feeding radiating portion 140 and the grounding element 130. In some embodiments, the coupling portion 150 has a vertical projection on the metal machine member 110, wherein the vertical projection at least partially overlaps the first closed end 121 of the slot 120 to fine tune the Impedance Matching (Impedance Matching) of the antenna structure 100.

The switching circuit 170 includes a first Metal part (Metal Element)180, a second Metal part 190, a reactive Element (reactive Element)185, a Capacitor (Capacitor) C, and a Diode (Diode) D. The first metal part 180 may have a substantially straight bar shape. The first metal part 180 includes a first portion 181 and a second portion 182, wherein the first portion 181 of the first metal part 180 is coupled to the first end 151 of the coupling part 150. The reactive element 185 is embedded in the first metal part 180, wherein the reactive element 185 is coupled in series between the first part 181 and the second part 182 of the first metal part 180. For example, the reactive element 185 may include an Inductor (Inductor) L, which may be a Fixed Inductor (Fixed Inductor) or a Variable Inductor (Variable Inductor), but is not limited thereto. The second metal part 190 may also be substantially in a straight bar shape, wherein the second metal part 190 and the first metal part 180 may be substantially parallel to each other. A middle portion of the second metal portion 190 may be coupled to the grounding element 130 through the capacitor C. In some embodiments, the antenna structure 100 further includes a Voltage generator (not shown) that generates and adjusts a Control Voltage Difference (VD) according to a processor instruction. The first metal part 180 and the second metal part 190 may be configured to receive the aforementioned control voltage VD. The diode D is coupled between the first metal part 180 and the second metal part 190, wherein the diode D is selectively Turned On or Off according to the control voltage VD. In detail, the diode D has an Anode (Anode) and a Cathode (Cathode), wherein the Anode of the diode D is coupled to the first metal part 180, and the Cathode of the diode D is coupled to the second metal part 190. However, the present invention is not limited thereto. In other embodiments, the anode of the diode D may be coupled to the second metal portion 190 and the cathode of the diode D is coupled to the first metal portion 180, wherein the polarity of the control voltage VD may be changed correspondingly.

Fig. 2A shows a Voltage Standing Wave Ratio (VSWR) diagram of the antenna structure 100 according to an embodiment of the invention. In the embodiment of fig. 2A, when the control voltage VD becomes smaller (e.g., the control voltage VD may be equal to 0V), the diode D is not turned on and the antenna structure 100 may cover a first Frequency Interval (Frequency Interval) FV 1. Fig. 2B shows a voltage standing wave ratio diagram of the antenna structure 100 according to another embodiment of the invention. In the embodiment of fig. 2B, when the control voltage VD becomes larger (for example, the control voltage VD may be larger than 1.5V), the diode D is turned on and the antenna structure 100 may cover a second frequency interval FV2 higher than the first frequency interval FV 1. For example, the first frequency interval FV1 may be between 2400MHz and 2470MHz, and the second frequency interval FV2 may be between 2430MHz and 2500 MHz. As can be seen from the measurements of fig. 2A and 2B, the antenna structure 100 may cover an operating frequency band entirely, which may be between 2400MHz and 2500MHz, or (and) may be between 5150MHz and 5850 MHz. Therefore, the antenna structure 100 can support wide band operation of wlan (wireless Local Area networks)2.4GHz/5GHz, wherein the switching circuit 170 is mainly used to increase the low frequency operation bandwidth of the antenna structure 100.

In some embodiments, the principles of operation of the antenna structure 100 may be as follows. The metal machine component 110 and the slot 120 thereof are excited by the feed-in radiation part 140 to form the aforementioned operation frequency band. The coupling part 150 and the feeding radiation part 140 generate mutual coupling effect, so that the range of the operating frequency band can be finely adjusted. According to the actual measurement result, when the diode D is not conducting, the coupling portion 150 is in a Floating (Floating) state and provides a shorter coupling length, so that the first frequency interval FV1 moves toward a relatively low frequency direction; when the diode D is turned on, the coupling portion 150 is Grounded (Grounded) and provides a longer coupling length, so that the second frequency interval FV2 moves in a relatively high frequency direction. For the antenna structure 100, the capacitor C can be regarded as a Short-Circuited Path (Short-Circuited Path), which can be used to block low-frequency ground noise; the inductor L can be regarded as an Open-circuit Path (Open-circuit Path), which can be used to block the high-frequency resonant current. On the other hand, the first protruding portion 145 of the feeding radiating portion 140 and the second protruding portion 135 of the grounding element 130 help to reduce the difficulty of manufacturing and soldering the antenna structure 100. If the first protruding portion 145 and the second protruding portion 135 are omitted, the feeding point FP and the grounding point GP can move to any edge of the feeding radiating portion 140 and any edge of the grounding element 130, respectively, without affecting the effect of the present invention.

Fig. 3 shows a Radiation Efficiency (Radiation Efficiency) diagram of the antenna structure 100 according to an embodiment of the invention, wherein a first curve CC1 represents the Radiation Efficiency of the antenna structure 100 when the diode D is not turned on, and a second curve CC2 represents the Radiation Efficiency of the antenna structure 100 when the diode D is turned on. As can be seen from the measurement results shown in fig. 3, the radiation efficiency of the antenna structure 100 can reach 30% or higher in the aforementioned operating frequency band (e.g., from 2400MHz to 2500MHz, and then from 5150MHz to 5850MHz), which can meet the practical application requirements of the general mobile communication device.

In some embodiments, the element dimensions of the antenna structure 100 may be as follows. The length L1 of the slot 120 (the length L1 from the first closed end 121 to the second closed end 122) may be approximately equal to 0.5 times the wavelength (λ/2) of the lowest frequency (e.g., 2400MHz) of the operating frequency band of the antenna structure 100. The length L2 of the feeding radiating part 140 (the length L2 from the first end 141 to the second end 142) may be substantially equal to 0.25 times the wavelength (λ/4) of the lowest frequency of the operating band of the antenna structure 100. In the feeding radiation part 140, the width W2 of the wider portion 144 may be 1 to 2 times (e.g., 1.5 times) the width W1 of the narrower portion 143. Length L3 of coupling portion 150 (length L3 from first end 151 to second end 152) may be approximately equal to 0.25 times wavelength (λ/4) of the lowest frequency of the operating band of antenna structure 100. The width of coupling gap GC1 may be between 0mm and 3mm (e.g., 1 mm). In addition, a Switchable Grounding Path (Switchable Grounding Path) is formed from the first portion 181 of the first metal portion 180, through the diode D, the second metal portion 190, and the capacitor C, and then to the Grounding element 130, and the length L4 thereof may also be substantially equal to 0.25 times the wavelength (λ/4) of the lowest frequency of the operating frequency band of the antenna structure 100. Therefore, when the diode D1 is turned on, the total coupling length of the coupling portion 150 can be regarded as the sum of the aforementioned length L3 and length L4, i.e., 0.5 times the wavelength (λ/2) of the lowest frequency of the operation frequency band of the antenna structure 100. The Inductance (Inductance) of the inductor L may be between 100nH and 200nH (e.g., 120 nH). The Capacitance (Capacitance) of the capacitor C may be between 2pF and 3pF (e.g., 2.7 pF). The Cut-In Voltage Difference (Cut-In Voltage Difference) of the diode D may be about 0.7V. The parameter ranges of the above elements are calculated according to a plurality of experimental results, which are helpful for optimizing the operating Bandwidth (Operation Bandwidth) and impedance matching of the antenna structure 100.

Fig. 4 shows a top view of an antenna structure 400 according to another embodiment of the invention. Fig. 4 is similar to fig. 1A. In the embodiment of fig. 4, a coupling portion 450 of the antenna structure 400 generally exhibits a relatively simple L-shape. The coupling portion 450 has a first end 451 and a second end 452, wherein the first end 451 of the coupling portion 450 is coupled to the first metal portion 180 of the switching circuit 170, and the second end 452 of the coupling portion 450 is an open end, which can extend between the feeding radiating portion 140 and the grounding element 130. The length L5 of the coupling portion 450 may be approximately equal to 0.25 times the wavelength (λ/4) of the lowest frequency of the operating band of the antenna structure 400. According to the actual measurement results, the antenna structure 400 can support the aforementioned broadband operation even if the coupling portion 450 does not have a complicated meandering structure. The remaining features of the antenna structure 400 of fig. 4 are similar to those of the antenna structure 100 of fig. 1A and 1B, so that similar operation effects can be achieved in both embodiments.

Fig. 5 is a top view of an antenna structure 500 according to another embodiment of the invention. Fig. 5 is similar to fig. 1A. In the embodiment of fig. 5, a switching circuit 570 of the antenna structure 500 includes a first metal portion 580, a second metal portion 590, an inductor L, a capacitor C, and a diode D, which are connected in a similar manner as the switching circuit 170 of fig. 1A. The main difference from the embodiment of fig. 1A is that the switching circuit 570 is adjacent to the narrower portion 143 of the feeding radiating part 140, rather than adjacent to the wider portion 144 of the feeding radiating part 140. In this design, the operating band between 5150MHz to 5850MHz can also be adjusted by switching the diode D, so as to increase the high frequency operating bandwidth of the antenna structure 500. The remaining features of the antenna structure 500 of fig. 5 are similar to those of the antenna structure 100 of fig. 1A and 1B, so that similar operation effects can be achieved in both embodiments.

Fig. 6 is a top view of an antenna structure 600 according to another embodiment of the invention. Fig. 6 is similar to fig. 1A. In the embodiment of fig. 6, a switching circuit 670 of the antenna structure 600 includes a first metal portion 680, a second metal portion 690, a first Resistor (Resistor) R1, a second Resistor R2, and a Bipolar Junction Transistor (BJT) 650. The first metal part 680 may have a substantially straight bar shape. The first metal part 680 includes a first portion 681 and a second portion 682, wherein the first portion 681 of the first metal part 680 is coupled to the first end 151 of the coupling part 150. The first resistor R1 is embedded in the first metal portion 680, wherein the first resistor R1 is coupled in series between the first portion 681 and the second portion 682 of the first metal portion 680. The second metal portion 690 may also be substantially in the shape of a straight bar. Second resistor R2 is embedded in second metal section 690, wherein second resistor R2 is coupled in series between first portion 691 and second portion 692 of second metal section 690. The first metal part 680 and the second metal part 690 may be used to receive the aforementioned control voltage VD. The bjt 650 may be an NPN type, which is operated according to the control voltage VD. In detail, the bjt 650 has an Emitter (Emitter), a Base (Base), and a Collector (Collector), wherein the Emitter of the bjt 650 is coupled to the ground element 130, the Base of the bjt 650 is coupled to the first portion 691 of the second metal portion 690, and the Collector of the bjt 650 is coupled to the first portion 681 of the first metal portion 680. However, the present invention is not limited thereto. In other embodiments, the bjt 650 may be replaced by a PNP type, wherein the polarity of the control voltage VD may be changed accordingly. The Resistance value (Resistance) of the first resistor R1 may be between 0 Ω to 1000k Ω, for example: 100k omega. The resistance value of the second resistor R2 may be between 0 Ω to 1000k Ω, for example: 1k omega. In this design, the bjt 650 can selectively couple the first metal portion 680 to the second metal portion 690 according to the control voltage VD, and the first resistor R1 and the second resistor R2 can be used to suppress low-frequency ground noise and high-frequency resonant current. The remaining features of the antenna structure 600 of fig. 6 are similar to those of the antenna structure 100 of fig. 1A and 1B, so that similar operation effects can be achieved in both embodiments.

Fig. 7 shows a schematic diagram of a mobile device 700 according to an embodiment of the invention. In the embodiment of fig. 7, the mobile device 700 includes an antenna structure 750, which may be the antenna structure described in any of fig. 1A-6. For example, the mobile device may be a smart phone, a tablet computer, or a notebook computer, which integrates the above-mentioned antenna structure, but is not limited thereto.

The present invention provides a novel antenna structure, which can cover the operation of a wide frequency band only by using a single slot and a switching circuit. When the antenna structure is applied to a mobile device integrating a metal machine component, the metal machine component can be regarded as an extension part of the antenna structure, so that the negative influence of the metal machine component on the communication quality of the mobile device can be effectively avoided. It should be noted that the present invention can further improve the design of the mobile device without digging any Antenna Window (Antenna Window) on the metal machine component. In summary, the present invention can achieve the advantages of small size, wide frequency band, and beautiful appearance, so it is very suitable for various Narrow frame (Narrow Border) mobile communication devices.

It is noted that the sizes, shapes, parameters, and frequency ranges of the above-described elements are not limitations of the present invention. The antenna designer can adjust these settings according to different needs. The antenna structure and the mobile device of the present invention are not limited to the states illustrated in fig. 1A to 7. The present invention may include only any one or more features of any one or more of the embodiments of fig. 1A-7. In other words, not all illustrated features may be required to implement the antenna structure and mobile device of the present invention at the same time.

Ordinal numbers such as "first," "second," "third," etc., in the specification and claims are not necessarily in sequential order, but are merely used to identify two different elements having the same name.

Although the present invention has been described in connection with the preferred embodiments, it is not intended to limit the scope of the invention, and one skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention.

Claims

1. An antenna structure, comprising:

a metal machine component having a slot;

a grounding element coupled to the metal machine component;

a feed-in radiation part coupled to the signal source, wherein the feed-in radiation part extends across the slot;

a coupling part adjacent to the feed-in radiation part, wherein a coupling gap is formed between the feed-in radiation part and the coupling part;

a dielectric substrate, wherein the feed-in radiation part and the coupling part are both arranged on the dielectric substrate; and

a switching circuit, comprising:

a first metal part coupled to the coupling part;

a reactive element coupled in series between the first and second portions of the first metal portion;

a second metal portion;

a capacitor, wherein the second metal portion is coupled to the ground element via the capacitor; and

and a diode coupled between the first metal part and the second metal part, wherein the diode is selectively conducted or not conducted according to a control voltage.

2. The antenna structure of claim 1 wherein the metal machine component is a metal back cover of a mobile device.

3. The antenna structure of claim 1 wherein the slot is a closed slot and has a first closed end and a second closed end.

4. The antenna structure of claim 1 wherein the grounding element is a grounding copper foil and extends from the metal frame member to the dielectric substrate.

5. The antenna structure according to claim 1, wherein the feeding radiating portion has a straight strip shape.

6. The antenna structure of claim 1, wherein the feeding radiating portion has a non-uniform width structure.

7. The antenna structure of claim 6, wherein the feed radiating element comprises a narrower portion and a wider portion, the wider portion having a vertical projection on the metal frame member, the vertical projection at least partially overlapping the slot.

8. The antenna structure of claim 7, wherein the feed radiating element further comprises a first protruding portion coupled to the positive pole of the signal source, the ground element further comprises a second protruding portion coupled to a negative pole of the signal source.

9. The antenna structure of claim 8, wherein the first protruding portion of the feed radiating portion is coupled to the narrower portion of the feed radiating portion.

10. The antenna structure of claim 1, wherein the coupling portion has a meandering structure.

11. The antenna structure of claim 1, wherein the diode has an anode and a cathode, the anode being coupled to the first metal portion and the cathode being coupled to the second metal portion.

12. The antenna structure of claim 1, wherein the first metal portion and the second metal portion each present a straight strip shape.

13. The antenna structure of claim 1, wherein the first metal portion and the second metal portion are for receiving the control voltage.

14. The antenna structure of claim 1, wherein when the control voltage is decreased, the diode is not turned on and the antenna structure covers a first frequency interval, and when the control voltage is increased, the diode is turned on and the antenna structure covers a second frequency interval higher than the first frequency interval.

15. The antenna structure of claim 1, wherein the antenna structure has an operating frequency band between 2400MHz and 2500MHz, or (and) between 5150MHz and 5850 MHz.

16. The antenna structure of claim 15 wherein the length of the slot is equal to 0.5 wavelengths of the lowest frequency of the operating band.

17. The antenna structure according to claim 15, wherein the length of the feeding radiating portion is equal to 0.25 times the wavelength of the lowest frequency of the operating band.

18. The antenna structure of claim 15, wherein the length of the coupling portion is equal to 0.25 wavelengths of the lowest frequency of the operating band.

19. An antenna structure, comprising:

a metal machine component having a slot;

a grounding element coupled to the metal machine component;

a switching circuit, comprising:

a first metal part coupled to the coupling part;

a first resistor coupled in series between the first portion and the second portion of the first metal portion;

a second metal portion;

a second resistor coupled in series between the first portion and the second portion of the second metal part; and

a BJT operating according to a control voltage, wherein the BJT has an emitter coupled to the ground element, a base coupled to the second metal portion, and a collector coupled to the first metal portion.

20. A mobile device, comprising:

a metal machine component having a slot;

a grounding element coupled to the metal machine component;

a switching circuit, comprising:

a first metal part coupled to the coupling part;

an inductor coupled in series between the first portion and the second portion of the first metal part;

a second metal portion;

a diode coupled between the first metal part and the second metal part, wherein the diode is selectively conducted or not conducted according to a control voltage;

wherein the metal machine component, the grounding element, the feed-in radiation part, the coupling part, the dielectric substrate and the switching circuit together form an antenna structure.