Base station antenna and its high-frequency radiation unit

Abstract

The present invention provides a base station antenna and a high-frequency radiation unit thereof. The high-frequency radiation unit includes a feeding balun, a dielectric substrate disposed on the top of the feeding balun, and two pairs of radiators with orthogonal polarizations and fed by the feeding balun. Each radiator includes a radiation patch and a decoupling circuit electrically connected to the radiation patch and used for reducing low-frequency parasitic radiation. The radiation patch and the decoupling circuit are disposed on opposite surfaces of the dielectric substrate. The high-frequency radiation unit provided by the present invention is provided with a decoupling circuit on the dielectric substrate. Through the decoupling circuit, the coupling signal of the low-frequency radiation unit adjacent to the high-frequency radiation unit can be effectively suppressed, and the parasitic radiation can be reduced. Therefore, the distance between the high-frequency and low-frequency radiation units can be reduced on the premise of ensuring good low-frequency electrical performance, realizing the miniaturization of the antenna. Secondly, since the decoupling circuit and the radiation patch are disposed on opposite surfaces of the dielectric substrate, the structure is simple and compact and is beneficial to cost control.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile communications, and in particular to a high-frequency radiation unit and a base station antenna using the high-frequency radiation unit. Background Art

[0002] With the rapid development of mobile communication technology, in the current environment of coexistence of multiple networks, the demand for the number of base station antennas has increased exponentially, and problems such as difficult site selection and inconvenient installation of base station antennas have become increasingly prominent. To save site and antenna feeder resources, multi-band and miniaturization have become the main development directions of base station antennas.

[0003] However, in a multi-band antenna system, to meet the demand for miniaturization, the array arrangements of different frequency bands are extremely compact, resulting in mutual coupling phenomena. For example, a low-frequency radiation unit will generate a certain excitation signal to its adjacent high-frequency radiation unit, thereby generating parasitic radiation, causing the pattern of the low-frequency signal to be distorted and the performance of the low-frequency signal to drop sharply. To solve this problem, the existing solutions generally increase the distance between the high- and low-frequency radiation units or design a radiation unit with a complex structure to achieve the decoupling function, which is not conducive to the miniaturization of the antenna and will also increase the manufacturing cost of the antenna. Summary of the Invention

[0004] The primary object of the present invention is to provide a high-frequency radiation unit with a simple and compact structure that can effectively reduce low-frequency parasitic radiation.

[0005] Another object of the present invention is to provide a base station antenna using the above high-frequency radiation unit.

[0006] To achieve the above objects, the present invention provides the following technical solutions:

[0007] As a first aspect, the present invention relates to a high-frequency radiation unit, including a feeding balun, a dielectric substrate disposed on the top of the feeding balun, and two pairs of radiators with orthogonal polarizations and fed by the feeding balun. The radiator includes a radiation sheet and a decoupling circuit electrically connected to the radiation sheet and used to reduce low-frequency parasitic radiation. The radiation sheet and the decoupling circuit are disposed on opposite surfaces of the dielectric substrate.

[0008] Preferably, the decoupling circuit includes a coupling disk equivalent to a capacitor and a transmission line equivalent to an inductor. Two ends of the transmission line are respectively connected to the coupling disk and the radiation sheet.

[0009] Preferably, a connection hole for electrically connecting to the feeding balun is opened at the center of the coupling disk.

[0010] Preferably, the radiation patch is disposed on a surface of the dielectric substrate close to the feeding balun. An avoidance hole is formed in the radiation patch at a position of the connection hole, and a diameter of the avoidance hole is larger than a diameter of the connection hole.

[0011] Further, the radiator further includes a connecting line disposed on the dielectric substrate and configured to connect the radiation patch and the decoupling circuit.

[0012] Preferably, a height of the feeding balun is 0.15 to 0.2 times a wavelength of a center frequency of the high-frequency radiation unit.

[0013] Further, the feeding balun includes a support base, a feeding piece and a feeding post both disposed on the support base. The feeding piece is electrically connected to the radiation patch, and the feeding post is electrically connected to the decoupling circuit.

[0014] Preferably, the support base is integrally formed.

[0015] Preferably, the radiation patch is disposed on a surface of the dielectric substrate close to the feeding balun. The feeding balun further includes a support post disposed on the support base and configured to support the dielectric substrate. A diameter of the support post is larger than a diameter of the feeding post, and the feeding post is coaxially disposed on a top of the support post relative to the support post.

[0016] As a second aspect, the present invention further relates to a base station antenna, including a reflector, a low-frequency radiation unit and the above-mentioned high-frequency radiation unit both disposed on the reflector.

[0017] Compared with the prior art, the solution of the present invention has the following advantages:

[0018] 1. In the high-frequency radiation unit provided by the present invention, a decoupling circuit is disposed on the dielectric substrate. Through the decoupling circuit, a coupling signal of a low-frequency radiation unit adjacent to the high-frequency radiation unit can be effectively suppressed, and parasitic radiation is reduced. Thus, the distance between the high-frequency and low-frequency radiation units can be reduced on the premise of ensuring good low-frequency electrical performance, and antenna miniaturization can be achieved. Secondly, since the decoupling circuit and the radiation patch are disposed on two opposite surfaces of the dielectric substrate, the structure is simple and compact and is beneficial to cost control.

[0019] 2. In the high-frequency radiation unit provided by the present invention, since a decoupling circuit is provided, an equivalent electrical length of the feeding balun is increased. When a height of the feeding balun is 0.15 to 0.2 times a wavelength of a center frequency of the high-frequency radiation unit, good impedance matching can be achieved. However, a height of a conventional high-frequency radiation unit is generally a quarter of a wavelength of a center frequency. The reduction of the height is more beneficial to the realization of antenna miniaturization.

[0020] 3. In the high-frequency radiation unit provided by the present invention, since the decoupling circuit is disposed on the dielectric substrate, the structure of the feeding balun can be greatly simplified, enabling the support base of the feeding balun to be integrally formed, thereby reducing the number of solder joints, improving the intermodulation stability and reducing the production cost.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description, which will become apparent from the following description or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0023] Figure 1 is a perspective view of the high-frequency radiation unit provided by an embodiment of the present invention;

[0024] Figure 2 is Figure 1 an exploded view of the high-frequency radiation unit shown;

[0025] Figure 3 is Figure 1 a schematic assembly structure diagram of the radiation sheet and the dielectric substrate in the high-frequency radiation unit shown;

[0026] Figure 4 is Figure 1 a schematic assembly structure diagram of the decoupling circuit and the dielectric substrate in the high-frequency radiation unit shown;

[0027] Figure 5 is Figure 1 a schematic assembly structure diagram of the radiator in the high-frequency radiation unit shown, where the solid line represents the structure on the front side of the dielectric substrate and the dashed line represents the structure on the back side of the dielectric substrate;

[0028] Figure 6 is Figure 1 a simulation result diagram of the return loss and isolation of the high-frequency radiation unit shown;

[0029] Figure 7 is the radiation pattern of the low-frequency signal of the base station antenna provided by an embodiment of the present invention;

[0030] Figure 8 is the radiation pattern of the low-frequency signal of the base station antenna using the existing high-frequency radiation unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be construed as a limitation to the present invention.

[0032] Those skilled in the art of the present technology can understand that, unless specifically stated otherwise, the term "including" used in the description of the present invention means the presence of the described features, integers, steps, operations, components and / or assemblies, but does not exclude the presence or addition of one or more other features, integers, steps, operations, components, assemblies and / or their groups. It should be understood that when we say that a component is "connected" to another component, it can be directly connected to other components, or there may also be intermediate components. The term "and / or" used here includes all or any unit and all combinations of one or more related listed items.

[0033] Figures 1 to 8 Collectively show a high-frequency radiation unit provided by an embodiment of the present invention, which belongs to a dual-polarized broadband radiation unit, with an operating frequency band of 1700 MHz to 2690 MHz and a relative bandwidth of about 45%. The high-frequency radiation unit is used to be installed on the reflector of a base station antenna for radiating and receiving communication signals. The structure of the high-frequency radiation unit is simple and compact, and can effectively reduce the parasitic radiation to the adjacent low-frequency radiation unit. When applied to a base station antenna, it is beneficial to realize the miniaturization of the antenna and improve the antenna performance.

[0034] As Figure 1 shown, the high-frequency radiation unit 1 includes a feeding balun 11, a dielectric substrate 12 and a radiator 13. The dielectric substrate 12 is disposed on the top of the feeding balun 11 and is supported and suspended by the feeding balun 11. There are two pairs of radiators 13, which are orthogonally polarized and disposed on the dielectric substrate 12 and are both used for radiating signals.

[0035] As Figure 2 shown, the feeding balun 11 includes a support base 111 and a feeding sheet 112. The support base 111 is provided with a card slot 1111 for embedding the feeding sheet 112. The feeding sheet 112 is embedded in the card slot 1111 and is electrically connected to the radiator 13, and the feeding sheet 112 is used to feed the radiator 13, and its feeding method can be direct feeding or coupled feeding.

[0036] Further, since there are two pairs of radiators 13, there are correspondingly two feeding sheets 112. Each pair of radiators 13 is fed by one feeding sheet 112, and the crossing positions of the feeding sheet 112 and the other feeding sheet 112 are mutually avoided through a bending structure.

[0037] Please combine with Figures 3 to 5 , in Figure 3 , the structure on the side of the dielectric substrate 12 close to the feeding balun 11 is shown. In Figure 4 , the structure on the side of the dielectric substrate 12 away from the feeding balun 11 is shown. In Figure 5 , the assembly structure of the radiator 13 on the front and back sides of the dielectric substrate 12 is shown. Each radiator 13 includes a radiation sheet 131 and a decoupling circuit 132 electrically connected to the radiation sheet 131. The decoupling circuit 132 is used to reduce low-frequency parasitic radiation. The radiation sheet 131 and the decoupling circuit 132 are disposed on opposite sides of the dielectric substrate 12.

[0038] Specifically, the decoupling circuit 132 includes a coupling disk 1321 equivalent to a capacitor and a transmission line 1322 equivalent to an inductor. The two ends of the transmission line 1322 are respectively connected to the coupling disk 1321 and the radiation sheet 131. That is, the decoupling circuit 132 is composed of a capacitor and an inductor connected in parallel. After the radiation sheet 131 is connected to the decoupling circuit 132, the coupling signal of the low-frequency radiation unit adjacent to the high-frequency radiation unit 1 can be suppressed, and the low-frequency parasitic radiation can be reduced. And because the decoupling circuit 132 and the radiation sheet 131 are disposed on opposite sides of the dielectric substrate 12, the overall structure is simple and compact, which is beneficial to cost control and realizes the miniaturization of the antenna.

[0039] In practical applications, for radiation units with different structures and sizes, as well as different layout structures in the antenna, by adjusting parameters such as the size of the coupling disk 1321 and the length and width of the transmission line 1322, the decoupling circuit 132 can be better adapted to the high-frequency radiation unit 1, and the low-frequency coupling signal can be effectively suppressed. Specifically, it can be adjusted in combination with the structure of the simulation test to ensure that both the return loss and the isolation degree can reach the preset values.

[0040] It should be understood that in this embodiment, the radiation sheet 131 is disposed on the side of the dielectric substrate 12 close to the feeding balun 11. In other embodiments, the radiation sheet 131 can also be disposed on the side of the dielectric substrate 12 away from the feeding balun 11. Correspondingly, the decoupling circuit 132 will be disposed on the side of the dielectric substrate 12 close to the feeding balun 11, and the radiation performance of this structure is equivalent to that of the high-frequency radiation unit 1 provided in this embodiment.

[0041] Preferably, a connection hole 1323 for electrically connecting with the feed balun 11 is formed in the center of the coupling disk 1321. A through hole 121 is formed in the dielectric substrate 12 corresponding to the position of the connection hole 1323. An avoidance hole 1311 is formed in the radiation sheet 131 at the position of the connection hole 1323, and the diameter of the avoidance hole 1311 is larger than that of the connection hole 1323.

[0042] As shown in Figure 2 , the feed balun 11 further includes a support column 113 and a feed column 114 provided on the support base 111. The diameter of the support column 113 is larger than that of the feed column 114, and the diameter of the support column 113 is smaller than that of the avoidance hole 1311. The feed column 114 is coaxially provided on the top of the support column 113 relative to the support column 113. Both the support column 113 and the feed column 114 are provided with four, and they are arranged in a rectangular array corresponding to the positions of the four radiators 13. The dielectric substrate 12 abuts against the end face of the support column 113 and is supported on the support base 111 by the support column 113. The feed column 114 passes through the avoidance hole 1311, the through hole 121 and the connection hole 1323 in sequence to realize electrical connection with the coupling disk 1321, and the radiation sheet 131 is insulated from the feed column 114 through the avoidance hole 1311.

[0043] As shown in Figure 5 , the radiator 13 further includes a connection line 133 provided on the dielectric substrate 12 and used for connecting the radiation sheet 131 and the decoupling circuit 132. The connection line 133 extends from the radiation sheet 131. One end of the transmission line 1322 away from the coupling disk 1321 is connected to one end of the connection line 133 away from the radiation sheet 131, and metalized vias for passing through the dielectric substrate 12 for connection are provided at the connection positions of both.

[0044] Preferably, the height of the feed balun 11 is 0.17 times the wavelength of the center frequency of the high-frequency radiation unit 1, while the height of the existing high-frequency radiation unit is generally one-fourth of the wavelength of the center frequency. Due to the provision of the decoupling circuit 132, the equivalent electrical length of the feed balun 11 is increased, and good impedance matching is still ensured after reducing the height of the feed balun 11. When applied in a multi-band antenna, it will not produce a large coupling effect with adjacent low-frequency radiation units, which is beneficial to the miniaturization of the antenna.

[0045] In other embodiments, according to different parameter requirements, the specific height of the feed balun 11 can be adjusted between 0.15 and 0.2 times the wavelength of the center frequency of the high-frequency radiation unit 1.

[0046] Preferably, the support base 111 is integrally formed, and specifically, it can be made by die-casting. Since both the radiation sheet 132 and the decoupling circuit 132 are provided on the dielectric substrate 12, there is no need to provide relevant circuit structures on the feeding balun 11, which can greatly simplify the feeding balun 11, enabling the support base 111 to be integrally formed, reducing the number of solder joints, improving the intermodulation stability of the high-frequency radiation unit 1 and reducing the production cost.

[0047] In Figure 6 the simulation results of the return loss and isolation of the high-frequency radiation unit 1 are shown. The line S11 and the line S22 show the return loss of the high-frequency radiation unit 1 in two polarization directions, and the line S21 is used to show the isolation between the two polarization directions of the high-frequency radiation unit 1. As can be seen from Figure 6 it, both the return loss and isolation of the high-frequency radiation unit 1 are at normal levels, and its radiation performance can be better realized when applied in an antenna.

[0048] As a second aspect, the present invention also relates to a base station antenna (not shown in the figure, the same below), including a reflector, a low-frequency radiation unit and the above-mentioned high-frequency radiation unit 1 both provided on the reflector. Since the structure of the high-frequency radiation unit 1 is compact and can effectively reduce the parasitic radiation to the adjacent low-frequency radiation unit, the layout of the base station antenna can be more compact, realizing miniaturization.

[0049] Please refer to Figure 7 and Figure 8 In Figure 7 the radiation pattern of the low-frequency signal of the base station antenna using the high-frequency radiation unit 1 is shown, and in Figure 8 the radiation pattern of the low-frequency signal of the base station antenna using the existing high-frequency radiation unit is shown. As shown in the figure, under the same compact layout, all parameters of the base station antenna provided in this embodiment are normal, while when using the existing high-frequency radiation unit, the radiation pattern of the base station antenna is significantly distorted and the performance cannot be guaranteed.

[0050] In summary, due to the adoption of the high-frequency radiation unit 1, the base station antenna provided in this embodiment can effectively avoid the coupling effect between high and low frequencies while realizing miniaturization, ensure good electrical performance, and improve the product competitiveness.

[0051] The above are only some embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A high-frequency radiation unit, characterized in that, It includes a feeding balun, a dielectric substrate disposed on the top of the feeding balun, and two pairs of radiators with orthogonal polarizations and fed by the feeding balun. The radiator includes a radiation patch and a decoupling circuit electrically connected to the radiation patch and used to reduce low-frequency parasitic radiation. The radiation patch and the decoupling circuit are disposed on opposite surfaces of the dielectric substrate. The decoupling circuit includes a coupling disk equivalent to a capacitor and a transmission line equivalent to an inductor. Two ends of the transmission line are respectively connected to the coupling disk and the radiation patch.

2. The high-frequency radiation unit according to claim 1, characterized in that, A connection hole for electrically connecting with the feeding balun is formed in the center of the coupling disk.

3. The high-frequency radiation unit according to claim 2, characterized in that, The radiation patch is disposed on a surface of the dielectric substrate close to the feeding balun. An avoidance hole is formed at a position of the connection hole on the radiation patch. The diameter of the avoidance hole is larger than that of the connection hole.

4. The high-frequency radiation unit according to claim 1, wherein The radiator further includes a connection line disposed on the dielectric substrate and used to connect the radiation patch and the decoupling circuit.

5. The high-frequency radiation unit according to claim 1, wherein The height of the feeding balun is 0.15 to 0.2 times the wavelength of the center frequency of the high-frequency radiation unit.

6. The high-frequency radiation unit according to claim 1, characterized in that, The feeding balun includes a support base, a feeding sheet and a feeding post both disposed on the support base. The feeding sheet is electrically connected to the radiation patch. The feeding post is electrically connected to the decoupling circuit.

7. The high-frequency radiation unit according to claim 6, characterized in that, The support base is integrally formed.

8. The high-frequency radiation unit according to claim 6, wherein The radiation patch is disposed on a surface of the dielectric substrate close to the feeding balun. The feeding balun further includes a support post disposed on the support base and used to support the dielectric substrate. The diameter of the support post is larger than that of the feeding post. The feeding post is coaxially disposed on the top of the support post relative to the support post.

9. A base station antenna, comprising a reflector, a high-frequency radiation unit and a low-frequency radiation unit both disposed on the reflector, characterized in that, The high-frequency radiation unit is the high-frequency radiation unit according to any one of claims 1 to 8.

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