High cross-polarization ratio antenna element, antenna and communication base station

Abstract

The present application discloses a high cross-polarization ratio antenna element, an antenna and a communication base station. Among them, the high cross-polarization ratio antenna element includes: an upper radiation patch, a lower radiation patch and a feeding network; the upper radiation patch is arranged parallel to and directly above the upper radiation patch; the output end of the feeding network is connected to the lower radiation patch; the lower radiation patch couples the upper radiation patch through air; the shapes of the upper radiation patch and the lower radiation patch are rectangular, circular and polygonal; the sizes of the upper radiation patch and the lower radiation patch are set according to the size of the antenna; extension patches are symmetrically arranged at both ends of the upper radiation patch, the shape of the extension patch is set according to the application scenario of the antenna, the size of the extension patch is set according to the frequency band of the antenna, and the extension patch is used to improve the cross-polarization ratio in the axial direction. By adopting the foregoing solution, the cross-polarization ratio of the antenna is effectively improved by improving the current distribution, and the structure is simple and the cost is lower.

Description

Technical Field

[0001] The present application relates to the technical field of mobile communication antennas, and in particular, to a high cross-polarization ratio antenna element, an antenna, and a communication base station. Background Art

[0002] With the rapid development of wireless communication, the requirements for communication systems are continuously increasing, resulting in continuous tension in communication resources. Research shows that using the orthogonal polarization characteristics of electromagnetic waves to design communication systems can enable dual-polarization systems to obtain higher communication system capacities. In order to increase the communication system capacity and reduce the influence of multipath fading, diversity techniques are widely used. Diversity technology is a powerful receiving technology in communication base station antennas that can significantly improve the performance of wireless links with relatively low-cost investments.

[0003] In base station antennas, diversity technology mainly uses dual-polarization antennas. A dual-polarization antenna combines two antennas with orthogonal polarization directions of +45° and -45° and operates in a dual-transmit and dual-receive mode simultaneously, greatly saving the number of antennas in each cell. At the same time, since ±45° are orthogonal polarizations, it effectively ensures a good effect of diversity reception. Among them, the polarization purity of the ±45° (or other orthogonal polarization methods) antenna is described using the concept of cross polarization. The cross-polarization ratio is specifically defined as the ratio of the main polarization component to the cross-polarization component. The larger the cross-polarization ratio, the stronger the signal orthogonality that can be obtained from the antenna, the smaller the correlation between the two signals, and the better the polarization effect.

[0004] Currently, the common method to improve the cross-polarization ratio of antennas is mainly to add a baffle around the antenna. However, this method not only increases costs but also, with the increasingly strict requirements for antenna size, there are fewer positions where the baffle can be placed. At the same time, adding a baffle will also significantly affect other performance indicators of the antenna. Therefore, how to improve the cross-polarization ratio of the antenna under the premise of limited space and without increasing additional costs is an urgent problem to be solved currently. Summary of the Invention

[0005] The present application provides a high cross-polarization ratio antenna element, an antenna, and a communication base station to solve the problem of how to improve the cross-polarization ratio of the antenna under the premise of limited space and without increasing additional costs.

[0006] In a first aspect, an embodiment of the present application provides a high cross-polarization ratio antenna element, including: an upper radiation patch, a lower radiation patch, and a feeding network;

[0007] The upper radiation patch is disposed parallel and directly above the lower radiation patch; the output end of the feeding network is connected to the lower radiation patch; the lower radiation patch couples the upper radiation patch through air;

[0008] The shapes of the upper radiation patch and the lower radiation patch are rectangular, circular, and polygonal; the sizes of the upper radiation patch and the lower radiation patch are set according to the size of the antenna;

[0009] Two extension patches are symmetrically arranged at both ends of the upper radiation patch. The shape of the extension patch is set according to the application scenario of the antenna, the size of the extension patch is set according to the frequency band of the antenna, and the extension patch is used to improve the cross-polarization ratio in the axial direction.

[0010] In one implementation manner in combination with the first aspect, the length of the extension patch is one-fourth of the diameter or length of the radiator, and the width of the extension patch does not exceed one-tenth of the diameter or length of the radiator.

[0011] In one implementation manner in combination with the first aspect, the extension patch is in a C shape, and the two ends of the opening are connected to the upper radiation patch. The two parallel sides are wide sides, and the sides connecting the wide sides are long sides.

[0012] In one implementation manner in combination with the first aspect, the long side of the extension patch is 10 mm, and the wide side of the extension patch is 2 mm.

[0013] In one implementation manner in combination with the first aspect, the shape of the upper radiation patch is circular, and the shape of the lower radiation patch is a regular octagon.

[0014] In one implementation manner in combination with the first aspect, the feeding network is a two-way power divider. The input port of the power divider is connected to the output end of the RF circuit for feeding. The length of the input link of the power divider is set according to the position of the RF output end of the antenna unit; the two output ports of the power divider are connected to the +45° polarization direction of the same polarization ports of the two antenna units. At the same time, the two output ports of the power divider in the other polarization direction are connected to the -45° polarization ports of the two dipole units, forming a ±45° cross-polarized dual array.

[0015] In a second aspect, some embodiments of the present application provide a high cross-polarization ratio antenna, including the high cross-polarization ratio antenna unit described in any one of the implementation manners of the first aspect.

[0016] In one implementation manner in combination with the second aspect, the high cross-polarization ratio antenna further includes: an antenna cover and an antenna metal base;

[0017] The antenna cover and the antenna metal base are connected to form a sealed cavity, and the high cross-polarization ratio antenna unit is arranged in the sealed cavity.

[0018] In a third aspect, some embodiments of the present application provide a communication base station, and the communication base station includes the high cross-polarization ratio antenna described in any one of the implementation manners of the second aspect.

[0019] The present application discloses a high cross-polarization ratio antenna element, an antenna, and a communication base station. The high cross-polarization ratio antenna element includes: an upper radiation patch, a lower radiation patch, and a feeding network; the upper radiation patch is disposed parallel and directly above the upper radiation patch; the output end of the feeding network is connected to the lower radiation patch; the lower radiation patch couples with the upper radiation patch through air; the shapes of the upper radiation patch and the lower radiation patch are rectangular, circular, and polygonal; the sizes of the upper radiation patch and the lower radiation patch are set according to the size of the antenna; extension patches are symmetrically disposed at both ends of the upper radiation patch, the shape of the extension patch is set according to the application scenario of the antenna, the size of the extension patch is set according to the frequency band of the antenna, and the extension patch is used to improve the cross-polarization ratio in the axial direction. With the foregoing solution, by improving the current distribution, the cross-polarization ratio of the antenna is effectively increased, and the structure is simple and the cost is lower. Description of the Drawings

[0020] To more clearly illustrate the technical solutions of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0021] Figure 1 is a polarization diagram provided by an embodiment of the present application;

[0022] Figure 2 is a structural diagram of a high cross-polarization ratio antenna element provided by an embodiment of the present application;

[0023] Figure 3 is a structural diagram of a radiation patch in a high cross-polarization ratio antenna element provided by an embodiment of the present application;

[0024] Figure 4 is a schematic diagram of the current distribution of the antenna before loading the extension patch provided by an embodiment of the present application;

[0025] Figure 5 is a schematic diagram of the current distribution of the antenna after loading the extension patch provided by an embodiment of the present application;

[0026] Figure 6 is a schematic diagram of the comparison of cross-polarization ratio data before and after loading provided by an embodiment of the present application;

[0027] Figure 7 is a structural diagram of a high cross-polarization ratio antenna provided by an embodiment of the present application;

[0028] Figure 8 is a side view of a high cross-polarization ratio antenna provided by an embodiment of the present application.

[0029] Among them, 1 - antenna unit; 11 - upper radiation patch; 111 - extended patch; 12 - lower radiation patch, 13 - feeding network; 131 - input port; 132 - output port; 2 - antenna cover; 3 - antenna metal base. Detailed implementation manners

[0030] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0031] The embodiments of the present application are described by taking a patch antenna as an example. This is mainly because the patch antenna has a simple structure, low cost, and small loss. Therefore, it is favored in many application scenarios. However, since the radiation pattern of the patch antenna belongs to the slot mode, when dual-polarized feeding is performed, its polarization is impure, resulting in poor cross-polarization of this type of antenna.

[0032] To better understand the cross-polarization ratio of the antenna, first study how the cross-polarization ratio is measured and calculated when the antenna is placed at ±45°. Since the 45° positions of the antenna under test and the source antenna are placed, there will inevitably be an angular deviation from the original main polarization position when the turntable rotates. Therefore, first record the angle α by which the measured antenna deviates from the original main polarization angle after the turntable rotates, and its cross-polarization deviates from the original main polarization angle β after the turntable rotates. As Figure 1 shown in the polarization schematic diagram, Figure 1 In the coordinate system schematic diagram established in, line A is the 45° main polarization we set on the XOY plane. When the turntable rotates, that is, the main polarization rotates along the X axis and rotates an angle to reach line B. At this time, the angle with the original main polarization line A is α; its cross-polarization orthogonal to the main polarization also rotates the same angle along the X axis when the turntable rotates and reaches the position of line C. At this time, the angle between line C and the main polarization line A is β.

[0033] The cross-polarization ratio can be obtained by simple mathematical calculation, that is, dividing the main polarization vector direction by the cross-polarization vector direction. That is, the cross-polarization ratio of the antenna can be obtained by using the cosine component cosα / cosβ.

[0034] For the axial direction, α = 0°, β = 90°, cosα / cosβ = ∞. Theoretically, its axial cross-polarization ratio will tend to infinity.

[0035] For the ±60° direction, we set that it rotates 60° along the X axis. Then α = 48°, β = 77°, cosα / cosβ = 3. Converting it to dB, 20lg3 = 9.542dB. This is the theoretical value of the ±60° cross-polarization ratio of our measured antenna system.

[0036] As can be seen from the above theoretical derivation, to improve the cross-polarization ratio of the antenna, the angles α between the rotated antenna and the original main polarization and β of the cross-polarization can be controlled, that is, the polarization components and directions of the antenna are controlled. Ultimately, controlling the polarization components and directions of the antenna is to control the current distribution on the antenna.

[0037] Therefore, to improve the cross-polarization ratio of the antenna and obtain an antenna with a high cross-polarization ratio, the embodiments of the present application first disclose a high cross-polarization ratio antenna element, such as Figure 2 and Figure 3 shown in Figure 2 Figure 1 shows an antenna element 1 of a ±45-degree polarization two-element array, and the antenna element 1 includes: an upper radiation patch 11, a lower radiation patch 12, and a feeding network 13.

[0038] The upper radiation patch 11 is arranged parallel to the upper radiation patch 11 directly above; the output end of the feeding network 13 is connected to the lower radiation patch 12; the lower radiation patch 12 is coupled to the upper radiation patch 11 through air. The lower radiation patch 12 and the feeding network 13 can be arranged on a PCB board.

[0039] Among them, the working principle of the antenna element 1 is as follows: the feeding network 13 can be a two-way power divider. The input port 131 of the power divider is connected to the output end of the RF circuit for feeding, and the input link length of the power divider can be designed according to the position of the RF output end of the antenna element; the two output ports 132 of the power divider are connected to the same polarization ports of two antenna elements, which is called the +45° polarization direction. At the same time, the two output ports 132 of the power divider in the other polarization direction are connected to the -45° polarization ports of two dipole elements, forming a ±45° cross-polarized dual array. The two output ports 132 of the power divider are respectively connected to the lower radiation patch 12 of the antenna, and the upper radiation patch 11 is coupled through air, thus forming a complete working link of the antenna element 1.

[0040] The shapes of the upper radiation patch 11 and the lower radiation patch 12 are rectangular, circular, and polygonal; the sizes of the upper radiation patch 11 and the lower radiation patch 12 are set according to the size of the antenna.

[0041] The setting of the radiation patches (the upper radiation patch 11 and the lower radiation patch 12) is determined according to the radiation frequency band of the antenna. For example, Figure 2 the antenna element in Figure 2 is applied to the 2.6 GHz frequency band. According to the wavelength λ = c / f (c is the speed of light, f is the operating frequency of the antenna), this is a patch antenna, and its size is theoretically about λ / 2. If the frequency increases, the size will be smaller; if the frequency is small, the size will be larger.

[0042] Such as Figure 3As shown, extension patches 111 are symmetrically arranged at both ends of the upper radiation patch 11. The shape of the extension patch 111 is set according to the application scenario of the antenna, the size of the extension patch 111 is set according to the frequency band of the antenna, and the extension patch 111 is used to improve the cross-polarization ratio in the axial direction.

[0043] In this embodiment, by arranging a device that can improve the cross-polarization ratio on the antenna radiation unit, the current distribution on the antenna radiation unit is improved, thereby improving the cross-polarization ratio of the antenna, and the structure is simple and the cost is lower.

[0044] Optionally, the length of the extension patch 111 is one-fourth of the diameter or length of the radiator, and the width of the extension patch 111 does not exceed one-tenth of the diameter or length of the radiator.

[0045] As the antenna frequency changes, the size of the antenna radiator (upper radiation patch 11 and lower radiation patch 12) will change, and the extension edge will also change accordingly. Experimental verification shows that the length of the extension patch 111 is generally 1 / 4 of the diameter or length of the radiator, and the width should not exceed 1 / 10 of the diameter or length of the radiator.

[0046] In addition, the shape of the extension patch 111 needs to be set according to the application scenario of the antenna, and no specific limitation is made here.

[0047] In one implementation, as Figure 3 shown, the shape of the upper radiation patch 11 is circular, and the shape of the lower radiation patch 12 is a regular octagon.

[0048] Optionally, the extension patch 111 is in a C shape, and the two ends of the opening are connected to the upper radiation patch 11. The two parallel sides are wide sides, and the sides connecting the wide sides are long sides.

[0049] Optionally, the long side of the extension patch 111 is 10 mm, and the wide side of the extension patch 111 is 2 mm.

[0050] Figure 3 In, the extension patch 111 is arranged on the circular upper radiation patch 11, and the number is 2, which are axially symmetrically arranged. Its shape is C-shaped, the long side L is 10 mm, and the wide side W of the extension patch 111 is 2 mm.

[0051] In order to further reflect the beneficial effects of the high cross-polarization ratio antenna unit disclosed in this application, the embodiments of this application also disclose the effect comparison between the above high polarization ratio patch antenna unit and the patch antenna in the prior art, which is specifically as follows:

[0052] Referring to Figure 4 and Figure 5 shown, Figure 4 is the current distribution of the antenna unit without the extended patch structureFigure 5 is the current distribution of the antenna unit with a loaded extended patch structure. From Figure 6 the data comparison of the cross-polarization ratio before and after loading disclosed by Figure 6 , it can be found that after loading the extended patch structure along the antenna axis, a small part of the current is generated at the extended patch, which enhances the radiation energy at that place, thereby changing the polarization energy distribution of the antenna in different directions, and thus improving the cross-polarization ratio of the antenna.

[0053] Based on the above-disclosed antenna unit, an embodiment of the present application also discloses a high cross-polarization ratio antenna, which includes the high cross-polarization ratio antenna unit in any of the above implementation manners.

[0054] Referring to Figure 7 and Figure 8 as shown, the high cross-polarization ratio antenna further includes: an antenna cover 2 and an antenna metal base 3.

[0055] The antenna cover 2 and the antenna metal base 3 are connected to form a sealed cavity, and the high cross-polarization ratio antenna unit is disposed in the sealed cavity.

[0056] Among them, the sealed cavity formed by the antenna cover 2 and the antenna metal base 3 can play a protective role, and the number of antenna units can be set according to actual needs.

[0057] Figure 8 In Figure 8 , the height L1 of the antenna cover 2 from the antenna metal base 3 (i.e., the height of the antenna cover 2) is 10 mm, and the distance L2 between the upper radiation patch 11 and the plane where the feeding network 13 is located (i.e., the PCB board) is 5 mm.

[0058] Based on the above-disclosed antenna unit, an embodiment of the present application also discloses a communication base station, which includes the high cross-polarization ratio antenna in any of the above implementation manners.

[0059] The present application has been described in detail above in combination with specific implementation manners and exemplary examples, but these descriptions should not be construed as limiting the present application. Those skilled in the art understand that without departing from the spirit and scope of the present application, various equivalent replacements, modifications or improvements can be made to the technical solutions and implementation manners of the present application, and these all fall within the scope of the present application. The protection scope of the present application is subject to the appended claims.

Claims

1. A high cross-polarization ratio antenna element, characterized in that, it includes: an upper radiation patch (11), a lower radiation patch (12) and a feeding network (13); the upper radiation patch (11) is arranged parallel and directly above the lower radiation patch (12); the output end of the feeding network (13) is connected to the lower radiation patch (12); the lower radiation patch (12) couples with the upper radiation patch (11) through air; the shapes of the upper radiation patch (11) and the lower radiation patch (12) are circular or polygonal; the sizes of the upper radiation patch (11) and the lower radiation patch (12) are set according to the size of the antenna; extension patches (111) are symmetrically arranged at both ends of the upper radiation patch (11), the shapes of the extension patches (111) are set according to the application scenario of the antenna, the sizes of the extension patches (111) are set according to the frequency band of the antenna, and the extension patches (111) are used to improve the cross-polarization ratio in the axial direction; the length of the extension patch (111) is one quarter of the diameter or length of the radiator, and the width of the extension patch (111) does not exceed one tenth of the diameter or length of the radiator; the extension patch (111) is in a C shape, and the two open ends are connected to the upper radiation patch (11), the two parallel sides are wide sides, and the sides connecting the wide sides are long sides.

2. The high cross-polarization ratio antenna element according to claim 1, characterized in that, the long side of the extension patch (111) is 10 mm, and the wide side of the extension patch (111) is 2 mm.

3. The high cross-polarization ratio antenna element according to claim 1, characterized in that, the shape of the upper radiation patch (11) is circular, and the shape of the lower radiation patch (12) is a regular octagon.

4. The high cross-polarization ratio antenna element according to claim 1, characterized in that, the feeding network (13) is a two-way power divider, the input port (131) of the two-way power divider is connected to the output end of the RF circuit for feeding, and the input link length of the two-way power divider is set according to the position of the RF output end of the antenna element; the two output ports (132) of the two-way power divider are connected to the same polarization port +45° polarization direction of two antenna elements, and at the same time the two output ports (132) of the power divider in the other polarization direction are connected to the -45° polarization ports of two dipole elements, forming a ±45° cross-polarized dipole array.

5. A high cross-polarization ratio antenna, characterized in that, it includes the high cross-polarization ratio antenna element according to any one of claims 1-4.

6. The high cross-polarization ratio antenna according to claim 5, characterized in that, the high cross-polarization ratio antenna further includes: an antenna cover (2) and an antenna metal base (3); the antenna cover (2) and the antenna metal base (3) are connected to form a sealed cavity, and the high cross-polarization ratio antenna element is arranged in the sealed cavity.

7. A communication base station, characterized in that, the communication base station includes the high cross-polarization ratio antenna according to claim 5 or 6.

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