CN103219582B - Communication device and its antenna structure - Google Patents

Abstract

The invention discloses a communication device and an antenna structure thereof, wherein the communication device comprises an antenna structure, wherein the antenna structure comprises: a ground element, one edge of which has a gap, and the long side of the gap is at least 2 times longer than the short side; an antenna element having a metal portion at the notch, two end points of the metal portion being far away from each other and substantially located at or near two opposite sides of the notch, wherein one end point is coupled to the ground element, and the other end point is a feed end of the antenna element; and a circuit component group, including at least a capacitance element and an inductance element, the capacitance element and the inductance element are coupled in series to the feed end, the circuit component group makes the antenna element generate a first resonance mode located in a first operation frequency band of the antenna element, and the length of the metal part is less than 0.18 times of the wavelength of the lowest frequency of the first operation frequency band. The antenna structure of the invention not only has simple manufacturing process, but also can reduce the production cost.

Description

Communication device and its antenna structure

technical field

The present invention relates to a communication device and its antenna structure, in particular to a mobile communication device with a small-sized half-loop antenna element and its antenna structure.

Background technique

With the rapid development of wireless communication technology, people's demands on mobile communication devices are becoming more and more diversified. In order to meet the user's multi-functional requirements, it is necessary to put more components into the mobile communication device with limited space, so as to increase the multi-functionality of the product. There is not much room for design in mobile communication devices, so antenna designers not only need to consider the requirements of antenna performance, but also need to evaluate the relationship between the antenna and other electronic components, or the integration of the antenna and the surrounding environment.

In order to solve the above problems, it is necessary to provide a small-sized antenna structure for a mobile communication device, which can be smaller than a quarter wavelength of the corresponding operating frequency band and provide good antenna performance.

Contents of the invention

The object of the present invention is to provide a communication device and its antenna structure, the communication device includes a half-loop antenna element, the length of which is less than the generally required resonance length of a quarter wavelength, to achieve a small antenna change.

The present invention provides a communication device, which includes an antenna structure, and the antenna structure includes: a grounding element, wherein an edge of the grounding element has a notch, and a long side of the notch is at least one short side of the notch More than twice the length; an antenna element, including a metal part located at the notch, wherein the two ends of the metal part are far away from each other and are generally located at or adjacent to the two opposite sides of the notch, and the two ends of the One is coupled to the ground element, and the other of the two terminals is a feed-in end of the antenna element; and a circuit element group including at least one capacitive element and an inductive element, wherein the capacitive element and the inductive element The element is coupled in series to the feed-in end, and the circuit element group causes the antenna element to generate a first resonance mode within a first operating frequency band of the antenna element, and the length of the metal part is shorter than the first operating frequency band. 0.18 times the wavelength of the lowest frequency of the band.

In addition, the present invention provides an antenna structure, comprising: a grounding element, wherein an edge of the grounding element has a notch, and a long side of the notch is at least twice the length of a short side of the notch; The antenna element includes a metal part located at the notch, wherein the two end points of the metal part are far away from each other and are approximately located at or adjacent to two opposite sides of the notch, and one of the two end points is coupled to the ground element, and the other of the two terminals is a feeding end of the antenna element; and a circuit element group including at least one capacitive element and an inductive element, wherein the capacitive element and the inductive element are coupled in series to the The feeding end, and the circuit element group causes the antenna element to generate a first resonance mode within a first operating frequency band of the antenna element, and the length of the metal part is less than 0.18 of the lowest frequency of the first operating frequency band times the wavelength.

In an embodiment structure of the present invention, the length of the antenna element is only about 45 mm, and the two ends of the antenna element are far away from each other. With the edges corresponding to the ground element and the antenna element, a current path similar to that of a loop antenna is formed. This enables the length of the antenna element to be greatly reduced compared with the resonant length required by a general loop antenna (with two ends of the antenna adjacent to each other). In the antenna element of the present invention, the excitation of the 900MHz frequency band is mainly through the external capacitance element, and the excitation of the 1800MHz frequency band is mainly through the external inductance element. In addition, adding an inductance component also helps to adjust the impedance matching of the 900MHz band. In other embodiments, a matching circuit can also be added to adjust the impedance matching of the two frequency bands. The invention can be directly formed on a dielectric substrate by printing or etching technology, which not only facilitates the manufacturing process, but also reduces the production cost.

In one embodiment of the present invention, the antenna element is a simple metal wire structure with a length of only about 45mm, which can cover at least GSM900/GSM1800 dual-band (880MHz-960MHz/1710MHz-1880MHz) operation. If the capacitive element, inductive element, and matching circuit are properly adjusted, GSM850/GSM1900 dual-band (824MHz～894MHz/1850MHz～1990MHz) operation can also be obtained, achieving the advantages of a small-sized antenna, wherein the length of the metal wire structure is shorter than that of the antenna 0.18 wavelengths of the lowest operating frequency of the component.

Description of drawings

FIG. 1 is a schematic diagram of a first embodiment of a communication device and its antenna structure of the present invention.

FIG. 2 is a schematic diagram of a second embodiment of the communication device and its antenna structure of the present invention.

FIG. 3 is a return loss diagram of the second embodiment of the communication device and its antenna structure of the present invention.

FIG. 4 is an antenna efficiency diagram of the second embodiment of the communication device and its antenna structure of the present invention.

FIG. 5 is a schematic diagram of a third embodiment of the communication device and its antenna structure of the present invention.

[Description of main reference signs]

100, 200, 500～communication device and its antenna structure;

10 ~ grounding element;

101～an edge of the grounding element;

11, 51 ~ gap;

12, 22, 52～antenna elements;

13, 23, 53 ~ Metal Department;

131, 231, 531 ~ the endpoint of the metal part;

132, 232, 532 ~ the other end of the metal part;

14～circuit component group;

141～capacitance element;

142～inductance element;

15 ~ matching circuit;

16～communication module;

233 ~ Part of the metal department;

31 ~ the first operating frequency band;

32 ~ the second operating frequency band;

41 ~ the antenna efficiency curve in the first operating frequency band;

42 ~ the antenna efficiency curve in the second operating frequency band;

t～one long side of the gap;

d ~ a short side of the gap.

detailed description

In order to make the above objects, features and advantages of the present invention more comprehensible, specific embodiments of the present invention are listed below and described in detail in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram of a first embodiment of a communication device 100 and its antenna structure according to the present invention. The communication device 100 includes an antenna structure, and the antenna structure includes a ground element 10 , an antenna element 12 , and a circuit element group 14 . There is a notch 11 at the edge 101 of the grounding element 10 , wherein the long side t of the notch 11 is at least twice the length of the short side d of the notch 11 . The antenna element 12 has a metal part 13 located at the notch 11 . The two end points 131 and 132 of the metal part 13 are far away from each other, and are approximately located at or adjacent to two opposite sides of the notch 11 , wherein the end point 131 is electrically coupled to the ground element 10 , and the other end point 132 is the feeding end of the antenna element 12 . The circuit element group 14 includes at least a capacitive element 141 and an inductive element 142 , wherein the capacitive element 141 and the inductive element 142 are connected in series and electrically coupled to the feeding end. In a preferred embodiment of the present invention, the capacitive element 141 may be a chip capacitor, and the inductive element 142 may be a chip inductor. Circuit element set 14 causes antenna element 12 to produce a first resonant mode within a first operating frequency band of antenna element 12 . The length of the metal portion 13 is less than 0.18 times the wavelength of the lowest frequency of the first operating frequency band. In an embodiment of the present invention, the communication device 100 and its antenna structure further include a matching circuit 15 and a communication module 16, wherein the matching circuit 15 is electrically coupled between the circuit element group 14 and the communication module 16 to adjust impedance match.

FIG. 2 is a schematic diagram of a second embodiment of a communication device 200 and its antenna structure according to the present invention. In the second embodiment, the metal portion 23 of the antenna element 22 of the communication device 200 has end points 231 and 232 , wherein the end point 231 is electrically coupled to the ground element 10 , and the other end point 232 is the feed end of the antenna element 22 . The plane where the part 233 of the metal part 23 is located is different from the plane where the notch 11 is located, and is substantially perpendicular to the plane where the notch 11 is located. Utilizing the part 233 of the metal part 23 can make the current flowing through the half-loop antenna more gentle, thereby effectively increasing the bandwidth. The remaining elements of the communication device 200 and its antenna structure are similar to the communication device 100 and its antenna structure of the first embodiment. In the second embodiment, the length of the grounding element 10 is about 120mm and the width is about 60mm; the length of the antenna element 12 is about 45mm; the length of the long side t of the notch 11 is about 40mm, and the length of the short side d is about 6mm .

3 is a return loss diagram of the second embodiment of the communication device 200 and its antenna structure of the present invention, wherein the vertical axis represents the return loss (unit: dB), and the horizontal axis represents the operating frequency (unit: MHz). The resonant mode of the antenna element 12 in the first operating frequency band 31 is mainly generated by an external capacitive element 141 (for example: a chip capacitor), while the resonant mode of the antenna element 12 in the second operating frequency band 32 is generated by an external inductive element 142 (for example: chip inductor) generated. If proper capacitance and inductance are selected, the antenna structure of the second embodiment can at least cover the dual-band operation of GSM900/1800 (880MHz-960MHz/1710MHz-1880MHz). In addition, if other appropriate capacitive elements 141, inductive elements 142 and matching circuits 15 are selected, the antenna structure can cover GSM850/1900 (824MHz～894MHz/1850MHz～ 1990MHz) dual-band. Therefore, the present invention can effectively adjust the resonance mode generated by the capacitive element 141 and the inductive element 142 to cover the required frequency band only by changing the impedance value of the circuit element group 14 when adjusting the requirements of different frequency bands. In other embodiments of the present invention, a switching circuit can be added to select some required elements of the circuit element group 14, or an integrated passive device (IPD) can be used to adjust the impedance value. This necessitates no further modification of the antenna element 12 .

4 is an antenna efficiency diagram of the second embodiment of the communication device 200 and its antenna structure of the present invention, wherein the vertical axis represents the antenna efficiency (%), and the two horizontal axes represent the operating frequency (unit: MHz). The antenna efficiency curve 41 corresponds to the lower horizontal axis and the antenna efficiency curve 42 corresponds to the upper horizontal axis. Antenna efficiency curve 41 represents the antenna efficiency of the antenna structure of the present invention in the GSM900 frequency band (880MHz～960MHz), and antenna efficiency curve 42 represents the antenna efficiency of the antenna structure of the present invention in the GSM1800 frequency band (1710MHz～1880MHz). The communication device and its antenna structure of the present invention have good antenna efficiency (radiation efficiency taking the S parameter into consideration) in both the GSM900 frequency band and the GSM1800 frequency band, which meets the requirements of practical applications.

FIG. 5 is a schematic diagram of a third embodiment of a communication device 500 and its antenna structure according to the present invention. In the third embodiment, the notch 51 of the communication device 500 is located approximately in the middle of the ground element 10 , and the metal portion 53 of the antenna element 52 is located in the notch 51 . One terminal 531 of the metal portion 53 is electrically coupled to the ground element 10 , and the other terminal 532 is electrically coupled to the feed-in terminal. The remaining elements of the communication device 500 and its antenna structure are similar to the communication device 100 and its antenna structure of the first embodiment. It should be noted that the present invention is different from conventional monopole antennas or inverted-F antennas. Since the antenna element 52 has no open end, the present invention has better tolerance to different ground plane environments.

Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the scope of the present invention. Any person skilled in the art may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore The scope of protection of the present invention should be determined by the scope defined by the appended claims.

Claims (8)

1. A communication device comprising an antenna structure comprising: A grounding element, wherein an edge of the grounding element has a notch, and a long side of the notch is at least twice as long as a short side of the notch; An antenna element, comprising a metal portion located at the notch, wherein two end points of the metal portion are far away from each other and approximately located at or adjacent to two opposite sides of the notch, and one of the two end points is coupled to the a ground element, and the other of the two endpoints is a feeding end of the antenna element; and A circuit element group including at least one capacitive element and an inductive element, wherein the capacitive element and the inductive element are coupled in series to the feed-in end, and the circuit element group causes the antenna element to generate a first a first resonant mode within the operating frequency band, and the length of the metal portion is less than 0.18 wavelengths of the lowest frequency of the first operating frequency band; Wherein, the notch is roughly located in the middle of the grounding element; Wherein the plane where a part of the metal part is located is different from the plane where the notch is located and is approximately perpendicular to the plane where the notch is located. 2. The communication device as claimed in claim 1, wherein the antenna element is further used to generate a second resonance mode within a second operating frequency band, and the frequency of the second operating frequency band is higher than the first operating frequency band Frequency of. 3. The communication device as claimed in claim 1, further comprising a matching circuit coupled between the circuit element group and a communication module. 4. The communication device as claimed in claim 1, wherein the capacitive element is a chip capacitor, and the inductive element is a chip inductor. 5. An antenna structure comprising: A grounding element, wherein an edge of the grounding element has a notch, and a long side of the notch is at least twice as long as a short side of the notch; An antenna element, comprising a metal portion located at the notch, wherein two end points of the metal portion are far away from each other and approximately located at or adjacent to two opposite sides of the notch, and one of the two end points is coupled to the a ground element, and the other of the two endpoints is a feeding end of the antenna element; and A circuit element group including at least one capacitive element and an inductive element, wherein the capacitive element and the inductive element are coupled in series to the feed-in end, and the circuit element group causes the antenna element to generate a first a first resonant mode within the operating frequency band, and the length of the metal portion is less than 0.18 wavelengths of the lowest frequency of the first operating frequency band; Wherein, the notch is roughly located in the middle of the grounding element; Wherein the plane where a part of the metal part is located is different from the plane where the notch is located and is approximately perpendicular to the plane where the notch is located. 6. The antenna structure as claimed in claim 5, wherein the antenna element is also used to generate a second resonance mode within a second operating frequency band, and the frequency of the second operating frequency band is higher than the first operating frequency band Frequency of. 7. The antenna structure as claimed in claim 5, further comprising a matching circuit coupled between the circuit element group and a communication module. 8. The antenna structure as claimed in claim 5, wherein the capacitive element is a chip capacitor, and the inductive element is a chip inductor.