Small-sized Dual-band Antenna and Communication Device

Abstract

The present invention provides a small-sized dual-band antenna and a communication device. The small-sized dual-band antenna includes a dielectric substrate, a first radiation unit, a second radiation unit, a balun structure, and a feeder line disposed on the dielectric substrate. The first radiation unit and the second radiation unit respectively radiate radiation signals in a first frequency band and a second frequency band to achieve dual-band radiation, eliminating the need to separately provide two sets of antennas. At the same time, the second radiation unit is bent to reduce the size of the dual-band antenna. The first radiation unit is disposed on both sides of the balun structure to form a stepped impedance transformation structure. The second radiation unit is disposed on both sides of the balun structure and bends towards the balun structure on both sides, thereby improving the relative bandwidth of the antenna. The overall structure is approximately axially symmetric, having a good radiation pattern.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a small-size dual-band antenna and a communication device. Background Art

[0002] With the continuous enhancement of people's requirements for communication quality and the integration of communication devices, as a sub-component of network communication terminals or electronic products, antennas also need higher performance to meet the needs of communication systems.

[0003] In recent years, in wireless communication, the radio frequency transceiver front-end is an important part of the entire system, and antennas are also constantly evolving with the update of the entire communication field. Currently, the number of antennas required for the WIFI product MIMO system is increasing continuously. Due to the limiting conditions brought by aspects such as the ID, structure, and PCB layout of the WIFI product, the available layout space for the antenna is insufficient, resulting in insufficient antenna isolation, which seriously affects the wireless indicators of the WIFI product. How to effectively reduce the number of antennas, improve the antenna isolation, while reducing the product cost and alleviating the hardware design difficulty poses a great challenge to antenna design. Summary of the Invention

[0004] The purpose of the present invention is to provide a small-size dual-band antenna, aiming to solve the two problems of integrating a small-size antenna within a limited device volume and reducing the number of antennas.

[0005] In a first aspect of an embodiment of the present invention, a small-size dual-band antenna is provided. The small-size dual-band antenna includes a dielectric substrate and a first radiation unit, a second radiation unit, a balun structure, and a feeder line disposed on the dielectric substrate;

[0006] The balun structure, the first radiation unit, and the second radiation unit are sequentially connected along a first direction. The first radiation unit has a stepped impedance transformation structure and is disposed on both sides of a first axis parallel to the first direction. The second radiation unit is strip-shaped and is disposed on both sides of the first axis. Two ends of the second radiation unit are bent towards a second direction opposite to the first direction with a preset length. The feeder line is electrically connected to the first radiation unit and the second radiation unit respectively;

[0007] The first radiation unit is used for radiating a radiation signal in a first frequency band, and the second radiation unit is used for radiating a radiation signal in a second frequency band;

[0008] The length of the first radiation unit is proportional to one-fourth of the resonant wavelength of the first frequency band;

[0009] The length of the second radiation unit is proportional to one-fourth of the resonant wavelength of the second frequency band.

[0010] In one embodiment, the balun structure is U-shaped and symmetrically disposed on both sides of the first axis.

[0011] In one embodiment, the first radiation unit includes a first radiation element and a second radiation element symmetrically disposed on both sides of the first axis. The first radiation unit and the second radiation unit are respectively connected to the balun structure. The width of the first radiation unit in a third direction perpendicular to the first axis gradually decreases, and the width of the second radiation unit in a fourth direction perpendicular to the third direction gradually decreases.

[0012] In one embodiment, the first radiation element includes a first radiation section and a second radiation section. The first radiation section and the second radiation section are arranged in a rectangular shape. The first radiation section is also connected to the balun structure. The first radiation section and the second radiation section are partially connected along the second direction and the fourth direction. The width of the first radiation section in the fourth direction is less than the width of the second radiation section in the fourth direction;

[0013] The second radiation element includes a third radiation section and a fourth radiation section. The third radiation section and the fourth radiation section are arranged in a rectangular shape. The third radiation section is also connected to the balun structure. The third radiation section and the fourth radiation section are partially connected along the second direction and the third direction. The width of the third radiation section in the third direction is less than the width of the fourth radiation section in the third direction.

[0014] In one embodiment, the small-size dual-band antenna further includes a first extension section. The first extension section is respectively connected to the third radiation section, the second radiation unit, and the feeder line. The first extension section is arranged in an L shape along the fourth direction and the first direction.

[0015] In one embodiment, the second radiation unit includes a third radiation element and a fourth radiation element disposed on both sides of the first axis;

[0016] The third radiation element is arranged in a strip shape and connected to the first radiation section. The fourth radiation element is arranged in a strip shape and connected to the third radiation section and the first extension section. The third radiation element is partially bent in the direction towards the first radiation element, and the fourth radiation element is partially bent in the direction towards the second radiation element.

[0017] In one embodiment, the third radiation element includes a connected fifth radiation section and sixth radiation section;

[0018] The fifth radiation section is also connected to the first radiation section. The sixth radiation section is partially bent in the direction towards the first radiation element;

[0019] The fourth radiation monomer includes a connected seventh radiation section and an eighth radiation section;

[0020] The seventh radiation section is also connected to the third radiation section and the first extension section, and the eighth radiation section is partially bent toward the second radiation monomer;

[0021] The end section of the sixth radiation section and the end section of the eighth radiation section are horizontally arranged, and the first extension section is arranged between the fifth radiation section and the seventh radiation section.

[0022] In one embodiment, the small-size dual-band antenna further includes a second extension section. The second extension section is connected to the fifth radiation section. The second extension section is arranged in a U shape. The first extension section is arranged between the fifth radiation section, the eighth radiation section and the second extension section. The feeder line is a coaxial cable. The inner conductor of the coaxial cable is electrically connected to the first extension section, and the outer conductor of the coaxial cable is connected to the second extension section.

[0023] In one embodiment, the resonant wavelength of the first frequency band is 5.15 GHz to 5.85 GHz, and the resonant wavelength of the second frequency band is 2.4 GHz to 2.5 GHz.

[0024] A second aspect of the embodiments of the present invention provides a communication device, and the communication device includes the small-size dual-band antenna as described above.

[0025] In the embodiments of the present invention, a small-size dual-band antenna is composed of a dielectric substrate and a first radiation unit, a second radiation unit, a balun structure and a feeder line arranged on the dielectric substrate. Among them, the first radiation unit and the second radiation unit respectively radiate radiation signals of the first frequency band and the second frequency band to achieve dual-band radiation, and there is no need to separately set two sets of antennas. At the same time, the second radiation unit is bent to reduce the size of the dual-band antenna. The first radiation unit is arranged on both sides of the balun structure in a stepped impedance transformation structure. The second radiation unit is arranged on both sides of the balun structure and both sides are bent toward the balun structure, thereby improving the relative bandwidth of the antenna. The overall structure is approximately axially symmetric and has a good radiation pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the small-size dual-band antenna provided by the embodiments of the present invention;

[0027] Figure 2 is Figure 1 a schematic diagram of the surface current of the small-size dual-band antenna shown;

[0028] Figure 3 is Figure 1 a 3D schematic diagram of the far-field radiation of the first frequency band of the small-size dual-band antenna shown;

[0029] Figure 4 For Figure 1 the 3D far - field radiation schematic diagram of the second frequency band of the small - size dual - band antenna shown in the figure. Specific embodiments

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0032] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0033] In the first aspect of the embodiment of the present invention, a small - size dual - band antenna is provided.

[0034] As Figure 1 shown in the figure, Figure 1 is the structural schematic diagram of the small - size dual - band antenna provided by the embodiment of the present invention. In this embodiment, the small - size dual - band antenna includes a dielectric substrate 100 and a first radiation unit 10, a second radiation unit 20, a balun structure 30 and a feeder line 40 disposed on the dielectric substrate 100;

[0035] The balun structure 30, the first radiation unit 10 and the second radiation unit 20 are sequentially connected along the first direction X1. The first radiation unit 10 has a stepped impedance transformation structure and is disposed on both sides of a first axis parallel to the first direction X1. The second radiation unit 20 is strip - shaped and is disposed on both sides of the first axis. The two ends of the second radiation unit 20 are bent toward the second direction X2 opposite to the first direction X1 with a preset length. The feeder line 40 is electrically connected to the first radiation unit 10 and the second radiation unit 20 respectively;

[0036] The first radiation unit 10 is used to radiate radiation signals of the first frequency band, and the second radiation unit 20 is used to radiate radiation signals of the second frequency band;

[0037] The length of the first radiation unit 10 is proportional to one - quarter of the resonance wavelength of the first frequency band;

[0038] The length of the second radiation unit 20 is proportional to one - quarter of the resonance wavelength of the second frequency band.

[0039] In this embodiment, the first radiation unit 10, the second radiation unit 20 and the balun structure 30 are connected to form a shape close to a "Chinese knot". The first - frequency - band radiation unit adopts a stepped impedance transformation structure to improve the impedance matching of the conversion, reduce the return loss, increase the bandwidth of the first frequency band. The second radiation unit 20 adopts a bent strip structure, making the second - frequency - band matching stable, widening the bandwidth, and reducing the size of the dual - frequency antenna. The balun structure 30 connects the first radiation unit 10 and the second radiation unit 20 together, truncates the high - frequency current outside the feeder line 40, and at the same time adjusts the matching of the two radiation units.

[0040] At the same time, since the first radiation unit 10 adopts a stepped impedance transformation structure, which has the advantages of miniaturization, easy adjustment of size, adjustable parasitic resonance frequency, etc., it is convenient to adjust the matching of the antenna in this frequency band, so that the first - frequency - band radiation antenna achieves better signal transmission and reception effects.

[0041] Among them, the first radiation unit 10 contributes to the first frequency band. The material length from the feeding point of the feeder line 40 and the first radiation unit 10 to the end of the first radiation unit 10 is one - quarter of the resonance wavelength of the first frequency band. The second radiation unit 20 contributes to the second frequency band. The material length from the feeding point of the feeder line 40 and the second radiation unit 20 to the end of the second radiation unit 20 is one - quarter of the resonance wavelength of the second frequency band. The first radiation unit 10 and the second radiation unit 20 form a multi - branch structure. Each branch operates in a different frequency band, forming multiple resonances and sharing the same feeder line 40. The length of the radiation unit of each branch can be adjusted separately to resonate to the corresponding frequency band, improving the radiation conversion efficiency.

[0042] The first radiation unit 10 has a stepped impedance transformation structure, and the number of its steps is not limited, and the direction of its stepped transformation is not limited, which is specifically set according to requirements.

[0043] At the same time, the bending angle of the second radiation unit 20 is specifically set according to various factors such as the dielectric substrate 100, the second frequency band and the size of the dual - frequency antenna, and no specific limitation is made here.

[0044] The balun structure 30 can be in the shape of a square, a circle, etc. In one embodiment, the balun structure 30 is U - shaped and symmetrically arranged on both sides of the first axis, forming axial symmetry. Combining the structures of the first radiation unit 10 and the second radiation unit 20, the dual - frequency antenna is approximately axially symmetric, making the dual - frequency antenna have an omnidirectional good radiation pattern.

[0045] The dielectric substrate 100 can be arranged in a square or circular shape. In one embodiment, in order to match the antenna structure and reduce the antenna size, the dielectric substrate 100 is arranged in a square shape.

[0046] The resonant wavelengths of the first frequency band and the second frequency band are obtained by correspondingly adjusting the size and shape of the dual-band antenna required by the communication device. In one embodiment, the resonant wavelength of the first frequency band is 5.15 GHz to 5.85 GHz, and the resonant wavelength of the second frequency band is 2.4 GHz to 2.5 GHz.

[0047] In the embodiment of the present invention, a small-size dual-band antenna is composed of a dielectric substrate 100 and a first radiation unit 10, a second radiation unit 20, a balun structure 30, and a feeder line 40 arranged on the dielectric substrate 100. Among them, the first radiation unit 10 and the second radiation unit 20 respectively radiate radiation signals of the first frequency band and the second frequency band to achieve dual-band radiation, and there is no need to separately set two sets of antennas. At the same time, the second radiation unit 20 is bent to reduce the size of the dual-band antenna. The first radiation unit 10 is arranged on both sides of the balun structure 30 in a stepped impedance transformation structure, and the second radiation unit 20 is arranged on both sides of the balun structure 30 and bends towards the balun structure 30 on both sides, thereby improving the relative bandwidth of the antenna. The overall structure is approximately axisymmetric and has a good radiation pattern.

[0048] Please continue to refer to Figure 1 , in one embodiment, the first radiation unit 10 includes a first radiation monomer 11 and a second radiation monomer 12 symmetrically arranged on both sides of the first axis. The first radiation unit 10 and the second radiation unit 20 are respectively connected to the balun structure 30. The width of the first radiation unit 10 gradually decreases in the third direction X3 perpendicular to the first axis, and the width of the second radiation unit 20 gradually decreases in the fourth direction X4 in the direction of the third direction X3.

[0049] In this embodiment, the width of the stepped structure of the first radiation monomer 11 and the second radiation monomer 12 close to the balun structure 30 is greater than the width of the adjacent stepped structure, so as to avoid the position of the second radiation monomer 12 close to the second radiation unit 20 being too large, resulting in a change in the antenna size, achieving the purpose of reducing the size of the dual-band antenna. At the same time, the isolation degree of the first radiation unit 10 and the second radiation unit 20 is improved to avoid interference between the two frequency bands. At the same time, the first radiation monomer 11 and the second radiation monomer 12 are combined into a stepped impedance transformation structure to improve the impedance matching of the conversion, reduce the return loss, and increase the bandwidth of the first frequency band.

[0050] Please continue to refer to Figure 1In one embodiment, the first radiation element 11 includes a first radiation section 11A and a second radiation section 11B. The first radiation section 11A and the second radiation section 11B are arranged in a rectangular shape. The first radiation section 11A is also connected to the balun structure 30. The first radiation section 11A and the second radiation section 11B are partially connected along the second direction X2 and the fourth direction X4. The width of the first radiation section 11A in the fourth direction X4 is less than the width of the second radiation section 11B in the fourth direction X4;

[0051] The second radiation element 12 includes a third radiation section 12A and a fourth radiation section 12B. The third radiation section 12A and the fourth radiation section 12B are arranged in a rectangular shape. The third radiation section 12A is also connected to the balun structure 30. The third radiation section 12A and the fourth radiation section 12B are partially connected along the second direction X2 and the third direction X3. The width of the third radiation section 12A in the third direction X3 is less than the width of the fourth radiation section 12B in the third direction X3.

[0052] In this embodiment, the first radiation element 11 includes two sections, and the second radiation element 12 includes two sections, thus combining into a stepped impedance transformation structure with a variable width. The first radiation section 11A and the third radiation section 12A are the transmission sections for the radiation signals of the first frequency band, and the second radiation section 11B and the fourth radiation section 12B are the transceiver sections for the radiation signals. The widths of the first radiation section 11A, the second radiation section 11B, the third radiation section 12A, and the fourth radiation section 12B can be correspondingly adjusted according to the reception effect of the dual-band antenna. The second radiation section 11B and the fourth radiation section 12B are far from the second radiation unit 20. In order to improve the isolation and meet the radiation conditions, the widths of the second radiation section 11B and the fourth radiation section 12B are greater than those of the first radiation section 11A and the second radiation section 11B.

[0053] In one embodiment, the small-size dual-band antenna further includes a first extension section 50. The first extension section 50 is respectively connected to the third radiation section 12A, the second radiation unit 20, and the feeder line 40. The first extension section 50 is arranged in an L shape along the fourth direction X4 and the first direction X1.

[0054] In this embodiment, the first radiation unit 10 is connected to the feeder line 40 through the first extension section 50. The first extension section 50 is arranged in an L shape, which can minimize the antenna oscillator on the basis of a limited size and at the same time integrate a small-size antenna within the limited volume of the device.

[0055] In one embodiment, the second radiation unit 20 includes a third radiation element 21 and a fourth radiation element 22 disposed on both sides of the first axis;

[0056] The third radiation monomer 21 is arranged in a strip shape and connected to the first radiation segment 11A. The fourth radiation monomer 22 is arranged in a strip shape and connected to the third radiation segment 12A and the first extension segment 50. The third radiation monomer 21 is partially bent towards the first radiation monomer 11, and the fourth radiation monomer 22 is partially bent towards the second radiation monomer 12.

[0057] In this embodiment, the third radiation monomer 21 and the fourth radiation unit are bent correspondingly according to the shapes of the first radiation unit 10, the first extension segment 50, the resonant wavelength of the second frequency band, and the antenna size. In order to reduce the size of the dual-band antenna, the third radiation monomer 21 and the fourth radiation monomer 22 are bent towards the first radiation unit 10, which can enable the dual-band antenna to obtain a larger radiation unit length within a limited space. At the same time, through the matching of the first extension segment 50, the first radiation unit 10 and the second radiation unit 20 are connected to match the high and low frequencies.

[0058] In one embodiment, the third radiation monomer 21 includes a connected fifth radiation segment 21A and a sixth radiation segment 21B;

[0059] The fifth radiation segment 21A is also connected to the first radiation segment 11A, and the sixth radiation segment 21B is partially bent towards the first radiation monomer 11;

[0060] The fourth radiation monomer 22 includes a connected seventh radiation segment 22A and an eighth radiation segment 22B;

[0061] The seventh radiation segment 22A is also connected to the third radiation and the first extension segment 50, and the eighth radiation segment 22B is partially bent towards the second radiation monomer 12;

[0062] The end segments of the sixth radiation segment 21B and the eighth radiation segment 22B are horizontally arranged, and the first extension segment 50 is arranged between the fifth radiation segment 21A and the seventh radiation segment 22A.

[0063] In this embodiment, the fifth radiation segment 21A and the seventh radiation segment 22A are the transmission segments of the radiation signals of the second frequency band, and the sixth radiation segment 21B and the eighth radiation segment 22B are the receiving and transmitting segments of the radiation signals. The sixth radiation segment 21B and the eighth radiation segment 22B are partially bent, which can enable the dual-band antenna to obtain a larger radiation unit length within a limited space. At the same time, in order to match the structure of the dielectric substrate 100, the end segments of the sixth radiation segment 21B and the eighth radiation segment 22B are horizontally arranged.

[0064] At the same time, the second radiation unit 20 adopts the fifth radiation segment 21A and the seventh radiation segment 22A for increasing the signal transmission end and the sixth radiation segment 21B and the eighth radiation segment 22B with a gradient structure, so that the second frequency band is stably matched and the bandwidth is widened.

[0065] In one embodiment, the small-sized dual-band antenna further includes a second extension section 60. The second extension section 60 is connected to the fifth radiation section 21A. The second extension section 60 is arranged in a U shape. The first extension section 50 is arranged between the fifth radiation section 21A, the eighth radiation section 22B, and the second extension section 60. The feeder line 40 is a coaxial cable. The inner conductor of the coaxial cable is electrically connected to the first extension section 50, and the outer conductor of the coaxial cable is connected to the second extension section 60.

[0066] In this embodiment, the feeder line 40 adopts a coaxial cable. The center of the U-shaped structure extended from the second radiation unit 20 is connected through the coaxial cable 00. The balun structure 30 chokes off the current flowing into the outer conductor of the coaxial cable, that is, cuts off the high-frequency current flowing through the outer conductor of the coaxial cable, and at the same time plays a role in impedance matching.

[0067] In this embodiment, the radiation sections in the first radiation unit 10 and the second radiation unit 20 are connected to form an antenna with a concave structure respectively. When fed at the midpoint of a reasonable size, orthogonal distributed currents at the two operating frequencies can be excited. The distributed currents are orthogonal in the radiation field pattern when observed in the far field, effectively reducing the mutual coupling between the two radiation units. The distributed currents and the field pattern are as Figures 2 to 4 .

[0068] The present invention also provides a communication device. The communication device includes a small-sized dual-band antenna. The specific structure of the small-sized dual-band antenna refers to the above embodiment. Since this communication device adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A small-sized dual-band antenna, characterized in that, It includes a dielectric substrate and a first radiation unit, a second radiation unit, a balun structure, and a feeder line disposed on the dielectric substrate; The balun structure, the first radiation unit, and the second radiation unit are sequentially connected along a first direction. The first radiation unit is a stepped impedance transformation structure and is disposed on both sides of a first axis parallel to the first direction. The second radiation unit is strip-shaped and is disposed on both sides of the first axis. Two ends of the second radiation unit are bent toward a second direction opposite to the first direction with a preset length. The feeder line is electrically connected to the first radiation unit and the second radiation unit respectively; The first radiation unit is used to radiate radiation signals in a first frequency band, and the second radiation unit is used to radiate radiation signals in a second frequency band; The length of the first radiation unit is proportional to one-fourth of the resonant wavelength of the first frequency band; The length of the second radiation unit is proportional to one-fourth of the resonant wavelength of the second frequency band; The small-size dual-band antenna further includes: A first extension section, through which the first radiation unit is connected to the feeder line; A second extension section, through which the second radiation unit is connected to the feeder line. Wherein, the feeder line is a coaxial cable. The inner conductor of the coaxial cable is electrically connected to the first extension section, and the outer conductor of the coaxial cable is connected to the second extension section; The first extension section is arranged in an L shape along a fourth direction and the first direction. The first axis is perpendicular to a third direction, and the fourth direction is opposite to the third direction; The second extension section is arranged in a U shape, and the coaxial cable is connected to the structural center of the second extension section.

2. The small-sized dual-band antenna according to claim 1, characterized in that, The balun structure is U-shaped and symmetrically disposed on both sides of the first axis.

3. The small-sized dual-band antenna according to claim 2, characterized in that, The first radiation unit includes a first radiation monomer and a second radiation monomer symmetrically disposed on both sides of the first axis. The first radiation unit and the second radiation unit are respectively connected to the balun structure. The width of the first radiation unit gradually decreases in the third direction, and the width of the second radiation unit gradually decreases in the fourth direction.

4. The small-sized dual-band antenna according to claim 3, characterized in that, The first radiation monomer includes a first radiation section and a second radiation section, which are arranged in a rectangle. The first radiation section is also connected to the balun structure. The first radiation section and the second radiation section are partially connected along the second direction and the fourth direction. The width of the first radiation section in the fourth direction is smaller than the width of the second radiation section in the fourth direction; The second radiation monomer includes a third radiation section and a fourth radiation section, which are arranged in a rectangle. The third radiation section is also connected to the balun structure. The third radiation section and the fourth radiation section are partially connected along the second direction and the third direction. The width of the third radiation section in the third direction is smaller than the width of the fourth radiation section in the third direction.

5. The small-sized dual-band antenna according to claim 4, characterized in that, The first extension section is respectively connected to the third radiation section, the second radiation unit, and the feeder line.

6. The small-sized dual-band antenna according to claim 5, characterized in that, The second radiation unit includes a third radiation element and a fourth radiation element disposed on both sides of the first axis; The third radiation element is arranged in a strip shape and connected to the first radiation section. The fourth radiation element is arranged in a strip shape and connected to the third radiation section and the first extension section. The third radiation element is partially bent in the direction towards the first radiation element, and the fourth radiation element is partially bent in the direction towards the second radiation element.

7. The small-sized dual-band antenna according to claim 6, characterized in that, The third radiation element includes a fifth radiation section and a sixth radiation section connected to each other; The fifth radiation section is further connected to the first radiation section, and the sixth radiation section is partially bent in the direction towards the first radiation element; The fourth radiation element includes a seventh radiation section and an eighth radiation section connected to each other; The seventh radiation section is further connected to the third radiation section and the first extension section, and the eighth radiation section is partially bent towards the second radiation element; The end sections of the sixth radiation section and the eighth radiation section are horizontally arranged, and the first extension section is disposed between the fifth radiation section and the seventh radiation section.

8. The small-sized dual-band antenna according to claim 7, characterized in that, The second extension section is connected to the fifth radiation section. The first extension section is disposed between the fifth radiation section, the seventh radiation section and the second extension section. The feeder line is a coaxial cable, and the inner conductor of the coaxial cable is electrically connected to the first extension section.

9. The small-sized dual-band antenna according to claim 1, characterized in that, The resonant wavelength of the first frequency band is 5.15 GHz to 5.85 GHz, and the resonant wavelength of the second frequency band is 2.4 GHz to 2.5 GHz.

10. A communication device, characterized in that, It includes a small-sized dual-band antenna according to any one of claims 1 to 9.

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