Small base station broadband antenna

Abstract

The present application provides a small base station broadband antenna, including an antenna unit and a metal carrier, wherein the antenna unit is arranged at the edge of the metal carrier. The antenna unit includes: a radiator, a circuit board, and a current path branch. The radiator is connected to the circuit board so as to be arranged on the metal carrier through the circuit board; the current path branch is a metal sheet structure connecting the radiator, and the current path branch is parallel to the metal carrier; the feeding current flows through the current path branch to form a construction current, so that the feeding current distribution path on the radiator is opposite to the ground current on the side close to the center of the metal carrier; and a compensation current path is formed to offset the reverse current on the radiator. The present application improves the radiation roundness by constructing an antenna to compensate for the radiation current, and has a simple structure, stable performance, and easy installation, thereby solving the problem of poor radiation roundness of existing broadband antennas.

Description

[0001] This application claims the priority of the Chinese patent application filed with the China Patent Office on April 27, 2020, with application number 202010346285.X and invention name “A Small Base Station Broadband Antenna”, the entire contents of which are incorporated by reference in this application. Technical Field

[0002] The present application relates to the field of antenna technology, and in particular to a small base station broadband antenna. Background Art

[0003] Small base stations, also known as micro base stations, are base station equipment with low transmission power and small coverage. They can share the load of macro base stations and improve network problems such as signal blind spots and weak coverage. In order to be compatible with 3G, 4G and 5G network systems, small base station antennas are required to be broadband, that is, they can support multiple frequency bands.

[0004] In order to further improve the transmission rate, multiple antennas (MIMO, Multiple-Input Multiple-Output) technology is applied to small base stations. Since it is necessary to ensure high isolation between adjacent bands in the antenna, avoid interference between adjacent antenna radiation units, and improve diversity gain and system channel capacity, the omnidirectional antenna of the small base station is usually placed at the edge of the metal carrier (rectangular or circular), but this will cause the antenna reference ground current distribution to be asymmetric, which will lead to chaotic current distribution at high frequencies for broadband antennas, affecting the signal radiation quality, deteriorating the radiation roundness of the antenna at high frequencies, and not conducive to achieving wide-range coverage.

[0005] In order to improve the radiation roundness of broadband antennas, the prior art can optimize the broadband roundness by changing the antenna structure or the coupling feeding method. For example, the Chinese patent with publication number CN107925151A discloses a method of using a coupling feeding method to make the current distribution of the metal carrier ground relatively symmetrical through an asymmetric antenna structure to improve the roundness; the Chinese patent with publication number CN106941213A discloses a method of adjusting the radiation directivity of the antenna radiation unit by adjusting the positions of multiple pairs of feeding points and grounding points on a sheet radiator; and the Chinese patent with publication number CN109216917A discloses a method of generating an omnidirectional radiation pattern in a wide bandwidth range through the center-fed conical grounded broadband planar inverted F antenna described in the patent.

[0006] However, the above methods all increase the complexity of the radiator or circuit structure, are not suitable for small base station environments, and are likely to affect the radiation area and radiation quality of the signal. At the same time, the above methods do not fundamentally solve the radiation roundness problem, resulting in insignificant improvement effects on the radiation roundness. Summary of the invention

[0007] The present application provides a small base station broadband antenna to solve the problem of poor radiation roundness of existing broadband antennas.

[0008] The present application provides a small base station broadband antenna, comprising a metal carrier and at least one antenna unit arranged on the metal carrier; the antenna unit is arranged at an edge position of the metal carrier; wherein the antenna unit comprises: a radiator, a circuit board and a current path branch;

[0009] The radiator is connected to the circuit board so as to be arranged on the metal carrier through the circuit board; the current path branch is a metal sheet structure connected to the radiator, and the current path branch is parallel to the metal carrier; the feeding current flows through the current path branch to form a structural current, so that the feeding current distribution path on the radiator is opposite to the ground current on the center side of the metal carrier; and a compensation current path is formed to offset the reverse current on the radiator.

[0010] Optionally, the antenna unit further includes a feeding pin; the radiator is a metal sheet structure; the radiator is connected to the circuit board via the feeding pin, and the radiator is parallel to the metal carrier.

[0011] Optionally, the antenna unit further includes a ground pin; a ground layer is provided on the circuit board, and the radiator is connected to the ground layer on the circuit board via the ground pin.

[0012] Optionally, the antenna unit includes two radiators and two current path branches; the two radiators and the two current path branches form a rectangular frame structure parallel to the metal carrier.

[0013] Optionally, the radiator is a rod-shaped radiating arm arranged on the metal carrier; one end of the radiator is connected to the metal carrier through the circuit board, and the other end is vertically connected to the current path branch.

[0014] Optionally, the current path branch is a U-shaped metal sheet structure, and the opening of the current path branch faces the center of the metal carrier; the radiator is connected to the middle position of the bottom edge of the current path branch.

[0015] Optionally, the current path branch is a hollow rectangular frame structure.

[0016] Optionally, the radiator and the current path branch are an integrated structure.

[0017] Optionally, the metal carrier is a rectangular metal plate, and four antenna units are respectively provided at four corners of the metal carrier.

[0018] Optionally, the circuit board is a PCB board that is bonded to an edge of the metal carrier.

[0019] It can be seen from the above technical solutions that the present application provides a small base station broadband antenna, including an antenna unit and a metal carrier, and the antenna unit is arranged at the edge of the metal carrier. Among them, the antenna unit includes: a radiator, a circuit board, and a current path branch. The radiator is connected to the circuit board so as to be arranged on the metal carrier through the circuit board; the current path branch is a metal sheet structure connecting the radiator, and the current path branch is parallel to the metal carrier; the feeding current flows through the current path branch to form a construction current, so that the feeding current distribution path on the radiator is opposite to the ground current on the side close to the center of the metal carrier; and a compensation current path is formed to offset the reverse current on the radiator. The present application improves the radiation roundness by constructing an antenna to compensate for the radiation current, and has a simple structure, stable performance, and easy installation, thereby solving the problem of poor radiation roundness of existing broadband antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 It is a schematic diagram of the structure of a symmetrical oscillator;

[0022] Figure 2 It is a schematic diagram of the current path structure when the radiator is set at the center of the metal carrier;

[0023] Figure 3 It is the radiation pattern of the radiation field in the horizontal direction when the radiator is set at the center of the metal carrier;

[0024] Figure 4 It is a schematic diagram of the current path structure when the radiator is arranged at the edge of the metal carrier;

[0025] Figure 5 It is the radiation pattern of the radiation field in the horizontal direction when the radiator is set at the edge of the metal carrier;

[0026] Figure 6 A schematic diagram of the structure of a broadband antenna for a small base station for this application;

[0027] Figure 7 This is a schematic diagram of the structure of the antenna unit of this application;

[0028] Figure 8 This is a schematic diagram of the structure of constructing a current path when the radiator of the present application is arranged at a corner of a metal carrier;

[0029] Fig. 9 This is a schematic diagram of the structure of constructing a current path when the radiator of the present application is arranged at the edge of a metal carrier;

[0030] Fig.10 This is a schematic diagram of a reverse current in this application;

[0031] Fig.11 This is a schematic diagram of the structure of the current path when the relative bandwidth of the present application reaches 40%-50%;

[0032] Fig.12 This is a schematic diagram of the current path branch structure of the hollow rectangular frame structure in this application;

[0033] Fig.13 The current distribution of the antenna unit at 1.7 GHz for this application;

[0034] Fig.14 The current distribution of the antenna unit at 2.7 GHz for this application;

[0035] Fig.15 Current distribution of the antenna unit at 3.6 GHz for this application. DETAILED DESCRIPTION

[0036] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.

[0037] In the technical solution provided in this application, the small base station broadband antenna provided can improve the overall radiation roundness of the antenna. In practical applications, conventional omnidirectional antennas usually place the antenna unit at the center of a metal carrier (reference ground), such as Figure 1 As shown. According to the mirror principle, a symmetrical oscillator can be constructed and the antenna radiation field can be obtained.

[0038]

[0039] The directional pattern function is:

[0040]

[0041] It can be seen that the current distribution on the metal carrier is centrally symmetrical, and the current directions on both sides of the radiator are opposite. Therefore, it can be concluded that the far-field radiation cancels each other out and there is no radiation, such as Figure 2 Correspondingly, the horizontal radiation pattern of the total radiation field is as follows: Figure 3 shown.

[0042] However, for small base stations, there is not enough space to place the radiator, so the radiator needs to be placed at the edge of the metal carrier. Figure 4 As shown. Due to the change in the boundary conditions on the reference ground, the current distribution is an asymmetric structure. Through the radiation principle, the far-field horizontal pattern can be obtained as follows Figure 5 As shown, the radiation circularity in a certain direction of the radiator is affected, so that a deeper concave point appears on the radiation pattern, and the circularity becomes worse.

[0043] In order to improve the radiation roundness of the antenna, the present application provides a small base station broadband antenna. Figure 6 , which is a structural diagram of a small base station broadband antenna in the present application.

[0044] like Figure 6 As shown, the small base station broadband antenna provided by the present application includes an antenna unit 1 and a metal carrier 2. Among them, the antenna unit 1 is used to generate and receive radio electromagnetic waves to achieve signal transmission and reception. The antenna unit 1 can select a monopole antenna, a microstrip patch antenna, a loop antenna, a PIFA antenna, a dipole antenna, etc. according to different actual application scenarios. The metal carrier 2 is a metal plate structure, which can provide support and perform grounding processing to serve as a reference ground for signal transmission.

[0045] In practical applications, multiple antenna units 1 can be arranged on the same metal carrier 2. Due to the small installation space of the small base station, the antenna unit 1 is arranged at the edge of the metal carrier 2. Multiple antenna units 1 can be arranged on the metal carrier 2 in different arrangements, for example, evenly distributed along the edge of the metal carrier 2. Depending on different application scenarios, the antenna unit 1 can be arranged on the metal carrier 2 near the edge or near the corner. For example, Figure 6 In the corresponding solution, the entire small base station antenna includes a metal carrier 2 and four antenna units 1. The metal carrier 2 is a rectangular metal plate, and four antenna units 1 are respectively arranged at the four corners of the metal carrier 2. Arranging multiple antenna units 1 on the metal carrier 2 can improve the signal transmission rate of the antenna in the radiation direction.

[0046] Since in the technical solution provided in the present application, the antenna unit 1 is also arranged at the edge of the metal carrier 2, the antenna unit 1 will also be affected by the boundary conditions on the reference ground, resulting in an asymmetric structure of the current distribution on the antenna unit 1, affecting the circularity of the signal radiation.

[0047] In order to improve the signal radiation roundness of the antenna unit 1, in this application, Figure 7As shown, the antenna unit 1 includes: a radiator 12, a circuit board 14 and a current path branch 15. The radiator 12 is connected to the circuit board 14 so as to be arranged on the metal carrier 2 through the circuit board 14. In practical applications, the radiator 12 can be set to different vibrator structures according to the specific antenna type of the antenna unit 1. For example, when the antenna unit 1 is a monopole antenna, the radiator 12 is a rectangular metal sheet structure. A signal processing module can be provided on or externally connected to the circuit board 14 to feed the radiator 12 so that the radiator 12 generates an electromagnetic signal in a specific form.

[0048] Furthermore, the circuit board 14 is a PCB (Printed Circuit Board) attached to the edge of the metal carrier 2. The PCB has grounding and power feeding functions.

[0049] The current path branch 15 is a metal sheet structure connected to the radiator 12, and the current path branch 15 is parallel to the metal carrier 2; the feeding current flows through the current path branch 15 to form a construction current, so that the feeding current distribution path on the radiator 12 is opposite to the ground current on the side close to the center of the metal carrier 2; and a compensation current path is formed to offset the reverse current on the radiator 12. In the technical solution provided by the present application, an equivalent current can be constructed on the side close to the edge through the current path branch 15, so that the current transmitted to the radiator 12 maintains the same boundary conditions in all directions, thereby improving the radiation roundness.

[0050] It can be seen that the present application constructs the antenna radiation current through the current path branch 15, thereby achieving the same ground current distribution as the radiator 12 in the center of the metal carrier 2, and improving the radiation roundness. The antenna designed by this method can achieve a better roundness of the antenna radiation pattern within a wider frequency band, and has a simple structure, stable performance, and easy installation.

[0051] In practical applications, in order to obtain a better roundness of the signal in the horizontal direction, it is necessary to construct a Figure 2 Similar boundary conditions for metal carriers, such as Figure 8 As shown, the antenna is placed at the corner of the reference ground. According to the mirror image principle, the horizontal current flow direction of the antenna's radiator is the same as the current flow direction of the structure, which can improve the horizontal radiation roundness.

[0052] Similarly, if the antenna radiator 12 is placed at the edge of the metal carrier 2, it is necessary to construct Fig. 9The radiation current direction shown in the figure will greatly improve the horizontal radiation roundness of the antenna. It can be seen that in some embodiments of the present application, the radiator 12 is a rod-shaped radiation arm arranged on the metal carrier 2; one end of the radiator 12 is connected to the metal carrier 2 through the circuit board 14, and the other end is vertically connected to the current path branch 15.

[0053] However, as the antenna operating frequency band becomes wider and wider, when the relative bandwidth reaches about 40%-50%, the current distribution in the high frequency band will be reversed, such as Fig.10 As shown, the roundness will deteriorate at high frequencies, and it is necessary to increase the current path so that the current flows in the required direction at high frequencies without reverse current, and the direction of the increased current path is perpendicular to the required current flow, which will not affect the overall radiation direction. The horizontal radiation direction still maintains a good roundness. At this time, the working wavelength of the antenna at high frequencies is 1 / 2 wavelength.

[0054] That is Fig.11 As shown, in some embodiments of the present application, the current path branch 15 is a U-shaped metal sheet structure, and the opening of the current path branch 15 faces the center of the metal carrier 2; the radiator 12 is connected to the middle position of the bottom edge of the current path branch 15.

[0055] When the relative bandwidth reaches more than 50%, Fig.11 The radiator 12 in the embodiment will also have reverse current at high frequency, which will affect the high frequency radiation roundness. Therefore, it is also necessary to increase the current path so that reverse current will not occur. Fig.12 As shown, the current path branch 15 can be a hollow rectangular frame structure, so as to form a compensation current path in the rectangular frame, so that there is no reverse current in the required current direction, and the current is vertical, which will not affect the overall radiation, and the horizontal radiation direction can still maintain a good roundness. At this time, the working wavelength of the antenna at high frequency is one wavelength.

[0056] It can be seen from the above technical solutions that in order to obtain a broadband or ultra-broadband antenna with good roundness in the horizontal radiation direction, the present application sets a current path branch 15 so that a similar current distribution is achieved in the entire bandwidth. Furthermore, if a reverse current occurs in the desired current flow direction, the added current branch 15 can eliminate the reverse current, thereby maintaining the antenna with good horizontal radiation roundness in the entire frequency band. Fig.13 , Fig.14 , Fig.15 As shown, the current distribution of the present application remains consistent within a wide frequency band, and a better horizontal radiation roundness can be obtained.

[0057] In some embodiments of the present application, in order to offset the reverse current and enhance the overall stability of the antenna, the radiator 12 and the current path branch 15 are an integrated structure. In addition, the antenna unit 1 also includes a feeding pin 13. The feeding pin 13 is used to feed the radiator 12 so that the radiator 12 generates electromagnetic radiation. The radiator 12 is a metal sheet structure, that is, a monopole antenna is formed by the metal sheet structure. The radiator 12 is connected to the circuit board 14 through the feeding pin 13, and the electrical signal on the circuit board 14 is transmitted to the radiator 12 by direct feeding, so that the radiator 12 generates a sending or receiving electromagnetic signal.

[0058] Since the compensation current path generated on the current path branch 15 needs to be perpendicular to the desired current flow direction (ie, the direction of the feeding pin 13 ), the current path branch 15 needs to be parallel to the metal carrier 2 , and the corresponding integrated radiator 12 is also parallel to the metal carrier 2 .

[0059] Furthermore, the antenna unit 1 further includes a ground pin 11; a ground layer is provided on the circuit board 14, and the radiator 12 is connected to the ground layer on the circuit board 14 through the ground pin 11. For example, the antenna unit 1 includes two radiators 12 and two current path branches 15; the two radiators 12 and the two current path branches 15 form a rectangular frame structure parallel to the metal carrier 2. Figure 6 , Figure 7 As shown, the top of the antenna unit 1 can be a hollow rectangular metal sheet, and the current path branches 15 and the radiator 12 are the four sides of the rectangular frame respectively. In actual applications, the circuit board 14 feeds the radiator 12 through the feeding pin 13. The current formed by the feeding is affected by the boundary conditions of the metal carrier 2, and a compensation current path will be formed on the radiator 12 and the current path branches 15 to offset the reverse current and maintain the radiation roundness of the antenna.

[0060] In practical applications, the antenna unit 1 can significantly improve the radiation roundness of the signal. It can be seen from the current distribution test of the antenna unit 1 under 1.7 GHz, 2.7 GHz and 3.6 GHz signals that Fig.12 , 11 As shown in Figure 14, the antenna unit 1 provided in the present application can maintain a consistent current distribution in a wide frequency band, and can obtain a good horizontal radiation roundness. Through actual test experiments, under different antenna signals. The antenna unit 1 provided in the present application has good roundness in the entire frequency band, among which the worst roundness value is -5.31dB, which also meets the requirements of small base stations for radiation roundness.

[0061] It can be seen from the above technical solutions that the present application provides a small base station broadband antenna, including an antenna unit 1 and a metal carrier 2, wherein the antenna unit 1 is arranged at the edge of the metal carrier 2. Among them, the antenna unit 1 includes: a radiator 12, a circuit board 14, and a current path branch 15. The radiator 12 is connected to the circuit board 14, so as to be arranged on the metal carrier 2 through the circuit board 14; the current path branch 15 is a metal sheet structure connecting the radiator 12, and the current path branch 15 is parallel to the metal carrier 2; the feeding current flows through the current path branch 15 to form a structural current, so that the feeding current distribution path on the radiator 12 is opposite to the ground current on the metal carrier 2 near the center side; and a compensation current path is formed to offset the reverse current on the radiator 12. The present application improves the radiation roundness by constructing an antenna to compensate for the radiation current, and has a simple structure, stable performance, and convenient installation, thereby solving the problem of poor radiation roundness of existing broadband antennas.

[0062] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims

1. A small base station broadband antenna, comprising a metal carrier (2) and at least one antenna unit (1) arranged on the metal carrier (2); the antenna unit (1) is arranged at an edge position of the metal carrier (2); characterized in that: The antenna unit (1) comprises: a radiator (12), a circuit board (14) and a current path branch (15); The radiator (12) is connected to the circuit board (14) so ​​as to be arranged on the metal carrier (2) through the circuit board (14); the current path branch (15) is a metal sheet structure connected to the radiator (12), and the current path branch (15) is parallel to the metal carrier (2); a feeding current flows through the current path branch (15) to form a structural current, so that the feeding current distribution path on the radiator (12) is opposite to the ground current on the side close to the center of the metal carrier (2); due to being at the boundary position, the current formed by the feeding forms a compensation current path on the radiator (12) and the current path branch (15); The antenna unit (1) comprises two radiators (12) and two current path branches (15); the two radiators (12) and the two current path branches (15) form a rectangular frame structure parallel to the metal carrier (2); The radiator (12) and the current path branch (15) are an integrated structure.

2. The small base station broadband antenna according to claim 1, characterized in that: The antenna unit (1) further comprises a feeding pin (13); the radiator (12) is a metal sheet structure; the radiator (12) is connected to the circuit board (14) via the feeding pin (13), and the radiator (12) is parallel to the metal carrier (2).

3. The small base station broadband antenna according to claim 1, characterized in that: The metal carrier (2) is a rectangular metal plate, and four antenna units (1) are respectively arranged at the four corners of the metal carrier (2).

4. The small base station broadband antenna according to claim 1, characterized in that: The circuit board (14) is a PCB board that is arranged on the edge of the metal carrier (2).

5. A small base station broadband antenna, comprising a metal carrier (2) and at least one antenna unit (1) arranged on the metal carrier (2); the antenna unit (1) is arranged at an edge position of the metal carrier (2); characterized in that: The antenna unit (1) comprises: a radiator (12), a circuit board (14) and a current path branch (15); The radiator (12) is connected to the circuit board (14) so ​​as to be arranged on the metal carrier (2) through the circuit board (14); the current path branch (15) is a metal sheet structure connected to the radiator (12), and the current path branch (15) is parallel to the metal carrier (2); a feed current flows through the current path branch (15) to form a construction current, and the distribution path of the construction current formed by the feed current flowing through the current path branch (15) is opposite to the direction of the ground current on the metal carrier (2) close to the center side; The radiator (12) is a rod-shaped radiating arm arranged on the metal carrier (2); one end of the radiator (12) is connected to the metal carrier (2) via the circuit board (14), and the other end is vertically connected to the current path branch (15); The current path branch (15) is a hollow rectangular frame structure, and the radiator (12) is connected to the middle position of the bottom edge of the current path branch (15), thereby forming a compensation current path in the rectangular frame.

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