Dual-band antenna structure and antenna system

Abstract

The present invention provides a dual-frequency antenna structure and antenna system, including a dielectric plate, a metal ground, a first antenna branch and a second antenna branch, the dielectric plate having a front side and a back side, the metal ground and the first antenna branch being arranged on the front side of the dielectric plate, and a feeding point being arranged between the metal ground and the first antenna branch, the second antenna branch being arranged on the back side of the dielectric plate, the dielectric plate having a metal via electrically connecting the first antenna branch and the second antenna branch, and the projections of the first antenna branch and the second antenna branch on the front side of the dielectric plate having an overlapping area. The dual-frequency antenna structure provided by the present invention adjusts the equivalent capacitance values ​​of the first antenna branch and the second antenna branch on the front and back sides of the dielectric plate by adjusting the size of the overlapping area, and flexibly adjusts the position of the resonant frequency point by using the equivalent capacitance loading effect, and can also adjust the frequency point of the antenna while keeping the volume of the antenna unchanged without adding antenna branches.

Description

Technical Field

[0001] The present invention belongs to the field of antenna technology, and more specifically, relates to a dual-frequency antenna structure and an antenna system. Background Art

[0002] The reason why dual-band antennas, such as dual-band WiFi antennas, have dual bands is that they have two antenna branches. Although this structural form of two antenna branches can achieve dual-band characteristics, it will inevitably increase the size of the antenna. When the size of antennas such as terminal antennas is limited, larger antennas cannot be used in compact devices, which is not conducive to the high integration of antennas. Summary of the invention

[0003] The object of the present invention is to provide a dual-frequency antenna structure to solve the technical problem of large size of the dual-frequency antenna in the prior art.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a dual-band antenna structure, including a dielectric plate, a metal ground, a first antenna branch and a second antenna branch, the dielectric plate has a front side and a back side, the metal ground and the first antenna branch are arranged on the front side of the dielectric plate, and there is a feeding point between the metal ground and the first antenna branch, the second antenna branch is arranged on the back side of the dielectric plate, the dielectric plate has a metal via electrically connecting the first antenna branch and the second antenna branch, and the projections of the first antenna branch and the second antenna branch on the front side of the dielectric plate have an overlapping area.

[0005] In one embodiment, the number of overlapping areas is three, namely, a first overlapping area, a second overlapping area and a third overlapping area; the first antenna branch includes a first metal segment and a second metal segment, the second antenna branch includes a third metal segment and a fourth metal segment, the first end of the first metal segment is the feeding point, the second end of the first metal segment and the first end of the third metal segment have the first overlapping area, the first end of the second metal segment and the second segment of the third metal segment have the second overlapping area, and the second end of the second metal segment and the first end of the fourth metal segment have the third overlapping area.

[0006] In one embodiment, the width of the first antenna branch and the width of the second antenna branch are both 0.5 mm.

[0007] In one embodiment, the third metal segment is L-shaped, the length of a section where the third metal segment overlaps with the first metal segment is 4 mm, and the length of a section where the third metal segment overlaps with the second metal segment is 10 mm.

[0008] In one embodiment, the length of the first overlapping area is 1 mm, the length of the second overlapping area is 3 mm, and the length of the third overlapping area is 3 mm.

[0009] In one embodiment, the length of the first metal segment is 4 mm, the length of the second metal segment is 10 mm, and the length of the fourth metal segment is 10 mm.

[0010] In one embodiment, the two frequency points of the dual-frequency antenna structure are 2.4 GHz and 5.8 GHz respectively.

[0011] In one embodiment, the second overlapping region is a current minimum point.

[0012] In one embodiment, the metal via is provided in the first overlapping area.

[0013] The present invention also provides an antenna system, comprising the above-mentioned dual-frequency antenna structure.

[0014] The dual-frequency antenna structure and antenna system provided by the present invention have the following beneficial effects: compared with the prior art, the dual-frequency antenna structure of the present invention includes a dielectric plate, a metal ground, a first antenna branch and a second antenna branch, the metal ground and the first antenna branch are arranged on the front side of the dielectric plate, and a feeding point is provided between the metal ground and the first antenna branch, and the second antenna branch is arranged on the back side of the dielectric plate. The dielectric plate has a metal via electrically connecting the first antenna branch and the second antenna branch, and an inductive loading effect is performed through the metal via.

[0015] An antenna with a single metal branch is called a monopole antenna. The monopole antenna has a quarter-wavelength resonance point frequency and a three-quarter-wavelength resonance point frequency. For example, when a quarter-wavelength resonance is generated at 2.4 GHz, a three-quarter-wavelength resonance point frequency is generated at 7.2 GHz. However, when these two frequencies do not match the two frequencies required by the antenna, such as the required frequencies of 2.4 GHz and 5.8 GHz, the prior art will add an antenna branch to meet the other frequency. This solution sets an overlapping area at the projection of the first metal branch and the second metal branch on the front of the dielectric plate, and adjusts the equivalent capacitance value of the first antenna branch and the second antenna branch on the front and back of the dielectric plate by adjusting the size of the overlapping area. The equivalent capacitance loading effect is used to flexibly adjust the position of the resonance frequency, so that the other frequency also meets the required frequency value. The frequency of the antenna can be adjusted without adding antenna branches and keeping the volume of the antenna unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 A schematic diagram of the front structure of a dual-frequency antenna structure provided by an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the back structure of a dual-frequency antenna structure provided by an embodiment of the present invention;

[0019] Figure 3 A perspective view of a dual-frequency antenna structure provided by an embodiment of the present invention;

[0020] Figure 4 A current distribution diagram of a dual-frequency antenna structure provided by an embodiment of the present invention;

[0021] Figure 5 The S11 simulation curves of the dual-frequency antenna structure provided in the embodiment of the present invention and the monopole antenna in the prior art.

[0022] Among them, the reference numerals in the figure are:

[0023] 1- dielectric board; 10- metal via; 11- first overlapping area; 12- second overlapping area; 13- third overlapping area; 2- metal ground; 3- first antenna branch; 31- first metal segment; 32- second metal segment; 4- second antenna branch; 41- third metal segment; 42- fourth metal segment; 5- feeding point. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 intended to limit the present invention.

[0025] 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.

[0026] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0028] The dual-frequency antenna structure provided by the embodiment of the present invention is now described.

[0029] See also Figures 1 to 3 In one embodiment of the dual-frequency antenna structure, the dual-frequency antenna structure includes a dielectric plate 1, a metal ground 2, a first antenna branch 3, and a second antenna branch 4. The dielectric plate 1 has a front side and a back side, the metal ground 2 and the first antenna branch 3 are arranged on the front side of the dielectric plate 1, and there is a feeding point 5 between the metal ground 2 and the first antenna branch 3, and the dual-frequency antenna structure is fed from the feeding point 5. The second antenna is arranged on the back side of the dielectric plate 1, and the dielectric plate 1 has a metal via 10 electrically connecting the first antenna branch 3 and the second antenna branch 4, and an inductive loading effect is performed through the metal via 10. The projections of the first metal branch and the second metal branch on the front side of the dielectric plate 1 have an overlapping area, and the equivalent capacitance value of the first antenna branch 3 and the second antenna branch 4 on the front and back sides of the dielectric plate 1 is adjusted by adjusting the size of the overlapping area, and the position of the resonant frequency point is flexibly adjusted by using the equivalent capacitance loading effect.

[0030] More specifically, an antenna with a single metal branch is called a monopole antenna. The monopole antenna has a quarter-wavelength resonance point frequency and a three-quarter-wavelength resonance point frequency. For example, when a quarter-wavelength resonance is generated at 2.4 GHz, a three-quarter-wavelength resonance point frequency is generated at 7.2 GHz. However, when these two frequencies do not match the two frequencies required by the antenna, such as the required frequencies of 2.4 GHz and 5.8 GHz, the prior art will add an antenna branch to meet the other frequency. This solution sets an overlapping area at the projection of the first metal branch and the second metal branch on the front of the dielectric plate 1, and adjusts the equivalent capacitance value of the first antenna branch 3 and the second antenna branch 4 on the front and back of the dielectric plate 1 by adjusting the size of the overlapping area. The equivalent capacitance loading effect is used to flexibly adjust the position of the resonance frequency, so that the other frequency also meets the required frequency value. The frequency of the antenna can be adjusted without adding antenna branches and keeping the volume of the antenna unchanged.

[0031] Optionally, the dielectric constant of the dielectric plate 1 is between 2-8.

[0032] See also Figure 3 In one embodiment of the dual-frequency antenna structure, the number of overlapping areas is three to meet the needs of frequency adjustment. The number of overlapping areas can also be one, two, four, etc., and the specific number is not limited here. When the number of overlapping areas is three, they are the first overlapping area 11, the second overlapping area 12 and the third overlapping area 13. Correspondingly, the first antenna branch 3 includes a first metal segment 31 and a second metal segment 32, and the second antenna branch 4 includes a third metal segment 41 and a fourth metal segment 42. The first end of the first metal segment 31 is a feeding point 5, and there is a first overlapping area 11 between the second end of the first metal segment 31 and the first end of the third metal segment 41, the first end of the second metal segment 32 and the second segment of the third metal segment 41 have a second overlapping area 12, and the second end of the second metal segment 32 and the first end of the fourth metal segment 42 have a third overlapping area 13. In this way, the dual-frequency antenna structure has three overlapping areas to meet the resonance requirements. When the length and position of the overlapping area change, the size of the two resonant frequency points will also change accordingly.

[0033] For further information, see Figure 3 The third metal segment 41 is L-shaped, so that the dual-frequency antenna structure is a monopole antenna. One end of the third metal segment 41 overlaps with the first metal segment 31 , and the other end of the third metal segment 41 overlaps with the second metal segment 32 .

[0034] See also Figure 4 , Figure 4The current distribution diagram of the dual-frequency antenna structure in the above embodiment when fed at 5.8GHz. The direction of the arrow is the direction of the current. It can be seen that the currents in the red circle are opposite to each other and the current here is the smallest. The effect of setting the overlapping area, i.e., the capacitor loading, is very obvious here. Figure 3 An overlapping area is set here to enhance the tuning effect.

[0035] See also Figures 1 to 3 In one embodiment of the dual-band antenna structure, the width of the first antenna branch 3 and the second antenna branch 4 are both 0.5mm. When the third metal segment 41 is L-shaped, the length of a section where the third metal segment 41 overlaps with the first metal segment 31 is 4mm, and the length of a section where the third metal segment 41 overlaps with the second metal segment 32 is 10mm. The length of the first overlapping area 11 is 1mm, the length of the second overlapping area 12 is 3mm, and the length of the third overlapping area 13 is 3mm. The length of the first metal segment 31 is 4mm, the length of the second metal segment 32 is 10mm, and the length of the fourth metal segment 42 is 10mm, so that when one of the frequency points of the dual-band antenna structure in this embodiment is 2.4GHz, the other frequency point can be adjusted to 5.8GHz through the setting of the above-mentioned overlapping area. In this way, the frequency point of the antenna is adjusted through the effect of capacitor loading, and no additional metal branches are required to ensure that the volume of the antenna remains unchanged to achieve the required dual frequency points. More specifically, when the two frequency points of the dual-band antenna structure are 2.4GHz and 5.8GHz respectively, the wifi frequency band is met.

[0036] Of course, first antenna branch 3 and second antenna branch 4 may also have other widths and lengths, and the sizes of first antenna branch 3 and second antenna branch 4 may be set according to the required frequency points, and the sizes are not limited here.

[0037] See also Figure 3 In one embodiment of the dual-frequency antenna structure, the metal via 10 is disposed in the first overlapping region 11. The first overlapping region 11, the second overlapping region 12, and the third overlapping region 13 are increasingly far from the feeding point 5. The metal via 10 is disposed in the first overlapping region 11, so that the second overlapping region 12 and the third overlapping region 13 can both form capacitive loads.

[0038] See also Figure 5 , Figure 5 for Figure 3 The S11 reflection coefficient simulation curve of the dual-frequency antenna structure and the ordinary monopole antenna in FIG. Figure 3The dielectric constant of the dielectric plate 1 is 6, and the specific dimensions are as follows: the width of the first antenna branch 3 and the second antenna branch 4 are both 0.5 mm. The third metal segment 41 is L-shaped, and the length of the section where the third metal segment 41 overlaps with the first metal segment 31 is 4 mm, and the length of the section where the third metal segment 41 overlaps with the second metal segment 32 is 10 mm. The length of the first overlapping area 11 is 1 mm, the length of the second overlapping area 12 is 3 mm, and the length of the third overlapping area 13 is 3 mm. The length of the first metal segment 31 is 4 mm, the length of the second metal segment 32 is 10 mm, and the length of the fourth metal segment 42 is 10 mm. The ordinary monopole antenna is arranged on one side of the dielectric plate 1, and the dielectric constant of the dielectric plate 1 is also 6. The width of the vertical segment and the horizontal segment of the ordinary monopole antenna are both 0.5 mm, the length of the vertical segment is 7 mm, and the length of the horizontal segment is 24 mm. Figure 5 In FIG. 1 , the horizontal axis is the resonant frequency, the vertical axis is the S11 reflection coefficient, and the dotted line is the S11 simulation curve in this embodiment, which is realized as the S11 simulation curve of a common monopole antenna. Figure 5 From the S11 simulation curve of this embodiment, it can be seen that the dual-band antenna structure of this embodiment has two frequency points 1 and 2 in the figure, which are 2.6GHz and 5.8GHz respectively, meeting the dual-band WiFi frequency point requirements. Figure 5 From the S11 curve of the ordinary monopole antenna, it can be seen that the antenna has two frequency points, 3 and 4, which are 2.5 GHz and 7.6 GHz respectively, namely the resonance point frequency of the quarter-wavelength mode and the resonance point frequency of the three-quarter-wavelength mode.

[0039] The present invention further provides an antenna system, which includes the dual-frequency antenna structure in any one of the above embodiments.

[0040] The antenna system of the above embodiment adopts the dual-frequency antenna structure of any of the above embodiments. The dual-frequency antenna structure sets an overlapping area in the projection of the first metal branch and the second metal branch on the front side of the dielectric plate 1. The equivalent capacitance value of the first antenna branch 3 and the second antenna branch 4 on the front and back sides of the dielectric plate 1 is adjusted by adjusting the size of the overlapping area. The position of the resonant frequency point is flexibly adjusted by using the equivalent capacitance loading effect, so that the other frequency point also meets the required frequency point value. The frequency point of the antenna can also be adjusted without adding antenna branches and keeping the volume of the antenna unchanged.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Dual-frequency antenna structure, characterized by: The invention comprises a dielectric plate, a metal ground, a first antenna branch and a second antenna branch, wherein the dielectric plate has a front side and a back side, the metal ground and the first antenna branch are arranged on the front side of the dielectric plate, and a feeding point is provided between the metal ground and the first antenna branch, the second antenna branch is arranged on the back side of the dielectric plate, the dielectric plate has a metal via electrically connecting the first antenna branch and the second antenna branch, and the projections of the first antenna branch and the second antenna branch on the front side of the dielectric plate have an overlapping area; the number of the overlapping areas is three, namely, a first overlapping area, a second overlapping area and a third overlapping area; the first antenna branch comprises a first metal segment and a second metal segment, the second The antenna branch includes a third metal segment and a fourth metal segment, the first end of the first metal segment is the feeding point, the second end of the first metal segment and the first end of the third metal segment have the first overlapping area, the first end of the second metal segment and the second segment of the third metal segment have the second overlapping area, and the second end of the second metal segment and the first end of the fourth metal segment have the third overlapping area; the width of the first antenna branch and the second antenna branch are both 0.5 mm, the third metal segment is L-shaped, the length of a section of the third metal segment overlapping with the first metal segment is 4 mm, and the length of a section of the third metal segment overlapping with the second metal segment is 10 mm.

2. The dual-frequency antenna structure according to claim 1, characterized in that: The length of the first overlapping area is 1 mm, the length of the second overlapping area is 3 mm, and the length of the third overlapping area is 3 mm.

3. The dual-frequency antenna structure according to claim 2, wherein: The length of the first metal segment is 4 mm, the length of the second metal segment is 10 mm, and the length of the fourth metal segment is 10 mm.

4. The dual-frequency antenna structure according to claim 3, characterized in that: The two frequency points of the dual-frequency antenna structure are 2.4 GHz and 5.8 GHz respectively.

5. The dual-frequency antenna structure according to claim 1, wherein: The second overlapping area is a current minimum point.

6. The dual-frequency antenna structure according to claim 1, wherein: The metal via is arranged in the first overlapping area.

7. An antenna system, characterized in that: It comprises the dual-frequency antenna structure as described in any one of claims 1 to 6.

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