WO2026019554A1

WO2026019554A1 - Base station antenna

Info

Publication number: WO2026019554A1
Application number: PCT/US2025/035835
Authority: WO
Inventors: Lin Wang; Haiyan Chen; Fangwen Wan; Hangsheng Wen
Original assignee: Outdoor Wireless Networks LLC
Current assignee: Outdoor Wireless Networks LLC
Priority date: 2024-07-15
Filing date: 2025-06-30
Publication date: 2026-01-22
Anticipated expiration: 2027-01-15
Also published as: CN121355616A

Abstract

A base station antenna comprises: a radome; X antenna arrays configured to be distributed annularly along the inner wall of the radome, wherein X ≥ 2; a feed network configured to have N RF ports and X feed ports connected to the X antenna arrays, with N ≤ X. The feed network comprises one or more 90-degree hybrid couplers that are connected to the N RF ports. The phase difference between the X antenna arrays is set by arranging the connection relationship between the X antenna arrays and the feed network to achieve quasi-omnidirectional antenna patterns.

Description

BASE STATION ANTENNA

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to Chinese Patent Application No. 202410949683.9, filed July 15, 2024, the entire content of which is incorporated herein by reference as if set forth fully herein.

FIELD

[0002] The present disclosure relates to the field of radio communications, and more specifically, to an omnidirectional base station antenna that may be used in MIMO communication systems

BACKGROUND

[0003] Wireless base stations are well known in the art, and generally include baseband units, radio equipment, antennas and other components. Antennas are configured to provide bidirectional radio frequency (“RF”) communication to fixed and mobile subscribers (“users”) located throughout a cell. Generally, antennas are installed on towers or raised structures such as poles, roofs, water towers, etc., and separate baseband units and radio equipment are connected to the antennas.

[0004] FIG. 1 is a structural schematic diagram of a conventional base station 10. The base station 10 comprises a base station antenna 15 that is capable of being mounted on an antenna tower 14. The base station 10 further comprises a baseband unit 11 and a radio unit 12. In order to simplify the attached drawing, a single baseband unit 11 and a single radio unit 12 are shown in FIG. 1. However, it should be understood that more than one baseband unit 11 and/or radio unit 12 may be provided. In addition, although the radio unit 12 is shown as being located at the same position as the baseband unit 11 at the bottom of the antenna tower 14, it should be understood that in other cases, the radio unit 12 may be a remote radio head (RRH) mounted on the antenna tower 14 adjacent to the base station antenna 15. The baseband unit 11 is capable of receiving data from another source (e.g., a backhaul network), and is capable of processing the data and providing a data stream to the radio unit 12. The radio unit 12 is capable of generating radio frequency signals including data encoded therein and is capable of amplifying and transmitting these radio frequency signals to the base station antenna 15 through a radio frequency cable 13 (e.g., a coaxial transmission cable). It should also be understood that the base station 10 of FIG. 1 may generally comprise various other devices (not shown), such as a power supply, a backup battery, a power bus, an Antenna Interface Standards Group (AISG) controller, and the like. Generally, a base station antenna includes one or more phased arrays of radiating elements, wherein the radiating elements are arranged in one or more columns when the antenna is installed for use.

[0005] Generally, in cellular communication systems, the geographic area is divided into a series of regions or “cells” served by corresponding base stations. Each base station may comprise one or more base station antennas that are configured to provide bidirectional RF communications to users within a cell served by the base station. In many cases, each base station is divided into “sectors”. In a common configuration, hexagonal cells are divided into three 120-degree sectors in the azimuth plane, and each sector is served by one or more base station antennas having an azimuth half power beam width of approximately 65°. Typically, base station antennas are mounted on towers or other elevated structures, with the radiation patterns generated by the base station antennas directed outward. Base station antennas are often realized as linear or planar phased arrays with radiating elements.

[0006] To increase capacity, base station antennas including beamforming arrays and/or configured to operate with multiple input multiple output (MEMO: Multiple-Input Multiple- Output) radio devices have been introduced in recent years. A beamforming array refers to an antenna array comprising a plurality of columns of radiating elements. Beamforming arrays are capable of generating antenna beams in, for example, a horizontal or “azimuthal” plane with a narrowed beamwidth, which increases the directionality or “gain” of the antenna, and thereby increasing the throughput that may be supported. MEMO refers to a communication technique in which data streams are divided into multiple fragments that are simultaneously transmitted over a plurality of relatively unrelated transmission paths between the transmitting station and the receiving station using certain coding techniques. A plurality of columns of antenna arrays may be used for MIMO transmission, wherein each column of an array may be connected to a port of a MEMO radio device and used to send/receive one of a plurality of data streams. In fact, since orthogonal polarizations tend to be highly uncorrelated, radiating elements in MIMO arrays are often implemented as dual-polarized radiating elements, allowing each column in the MIMO array to be connected to two ports on the radio device (wherein the first port is connected to a first polarization radiator of the radiating elements in the column, and the second port is connected to a second polarization radiator of the radiating elements in the column). This technique can effectively reduce the number of columns of radiating elements required by half, as each of the physical columns of the array comprises two independent radiator columns.

SUMMARY

[0007] A brief overview of the present disclosure is given below in order to provide a basic understanding of some aspects of the present disclosure. However, it should be understood that this overview is not an exhaustive overview of the present disclosure. It is not intended to be used to determine a critical or important part of the present disclosure, nor is it intended to be used to define the scope of the present disclosure. The purpose is merely to provide certain concepts of the present disclosure in simplified form as a preamble to the more detailed description provided later.

[0008] According to a first aspect of the present disclosure, a base station antenna is provided, comprising: a radome; X antenna arrays configured to be distributed annularly along the inner wall of the radome, wherein X > 2; a feed network configured to have N RF ports and X feed ports connected to the X antenna arrays, and N < X, wherein the feed network comprises a plurality of 90-degree hybrid couplers connected to the N RF ports, and wherein, by arranging the connection relationship between the X antenna arrays and the feeding network, phase differences between the X antenna arrays are set to achieve a quasi -omnidirectional antenna pattern.

[0009] In some examples, the X antenna arrays comprise dual-polarized antenna elements, wherein the feed network comprises a first feed network for feeding a first polarization direction and a second feed network for feeding a second polarization direction. [0010] In some examples, when X is 4, the first antenna array and the third antenna array, positioned at an angle of 180 degrees with respect to the central axis of the radome, are arranged to be fed by a first power divider, and the second antenna array and the fourth antenna array are arranged to be fed by a second power divider.

[0011] In some examples, the feeding method of the radiating elements is configured such that the initial phase of the first antenna array and the fourth antenna array is the first phase, and the initial phase of the second antenna array and the third antenna array is the second phase, wherein the phase difference between the second phase and the first phase is -180 degrees.

[0012] In some examples, for the same polarization direction, the feed points of the second antenna array and the third antenna array are oriented opposite to those of the first antenna array and the fourth antenna array to achieve the aforementioned phase difference.

[0013] In some examples, for the same polarization direction, the aforementioned phase difference is achieved by altering the length difference between the feed cables of the second antenna array and the third antenna array relative to the feed cables of the first antenna array and the fourth antenna array.

[0014] In some examples, when X is 3, the feed network includes a third power divider and a 90-degree hybrid coupler, wherein the output power of the first output port of the 90- degree hybrid coupler is twice that of the second output port, and the first output port is configured to connect to the third power divider to feed the first antenna array and the second antenna array, while the second output port directly powers the third antenna array.

[0015] In some examples, the radome has a cylindrical or prismatic shape.

[0016] In some examples, the base station antenna further comprises a reflector, wherein the X antenna arrays are arranged on the reflector, and the reflector has the shape of a regular prism or an approximately regular prism.

[0017] In some examples, the X antenna arrays are distributed on the outer surface of the reflector in a centrally symmetrical position relative to the central axis of the reflector.

[0018] In some examples, when X is 6, the shape of the reflector may be a regular triangular prism or a regular hexagonal prism, wherein when the reflector has the shape of a regular triangular prism, two columns of radiating elements are arranged on each side of the reflector; and when the reflector has the shape of a regular hexagonal prism, one column of radiating elements is arranged on each side of the reflector. [0019] In some examples, when X is 8, the shape of the reflector may be a regular quadrilateral prism or a regular octagonal prism, wherein when the reflector has the shape of a regular quadrilateral prism, two columns of radiating elements are arranged on each side of the reflector; and when the reflector has the shape of a regular octagonal prism, one column of radiating elements is arranged on each side of the reflector.

[0020] According to a second aspect of the present disclosure, a MIMO base station antenna is provided, wherein it comprises: a radome; X antenna arrays configured to be distributed annularly along the inner wall of the radome; a feed network configured to have X feed ports connected to the X antenna arrays, wherein the feed network comprises one or more 90-degree hybrid couplers to achieve a doubled number of ports for MIMO communication.

[0021] In some examples, the feed network has N RF ports provided by the one or more 90-degree hybrid couplers.

[0022] In some examples, the X array of antennas includes dual-polarized antenna elements and the base station antenna is implemented with a communication configuration of 2N transmitting antennas and 2N receiving antennas based on the feed network.

[0023] In some examples, a 4T4R configuration may be achieved when N is 2. In some examples, an 8T8R configuration may be achieved when N is 4.

[0024] An advantage of examples in accordance with the present disclosure is that a low- cost, compact omni-directional base station antenna is provided that can achieve double the number of antenna transceiver ports while substantially maintaining the size of a traditional omnidirectional antenna. For example, it can realize a 4T4R configuration using the basic size of the traditional 2T2R configuration, or realize a 8T8R configuration using the basic size of the traditional 4T4R configuration, etc.

[0025] Another advantage of the examples disclosed herein is the ability to change the phase difference between the various antenna arrays by arranging the connection relationship between the antenna arrays and the feed network, as well as by altering the feed connection method to preset the relative phase of the antenna arrays. This ensures that while achieving quasi-omni directional radiation patterns, the precoding patterns under transmission modes such as closed-loop spatial multiplexing (TM4: transmission mode 4) exhibit good orthogonality characteristics, thereby maximizing MIMO performance. [0026] It should be appreciated that the above advantage does not need to be achieved in one or some particular examples, but may be partially dispersed in different examples according to the present disclosure. The examples according to the present disclosure may have one or some of the above advantages, and may alternatively or additionally have other advantages.

[0027] Through the following detailed description of exemplary examples of the present disclosure by referencing the attached drawings, other features and advantages of the present disclosure will become clearer.

BRIEF DESCRIPTION OF THE DRAWING

[0028] The foregoing and other features and advantages of an example of the present disclosure will become clear from the following descriptions of the examples of the present disclosure shown in conjunction with the attached drawings. The attached drawings are incorporated herein and form a part of the Specification to further explain the principles of the present disclosure and enable those skilled in the art to make and use the present disclosure. In which:

[0029] FIG. 1 shows a structural schematic diagram of a conventional base station.

[0030] FIG. 2A to FIG. 2B show schematic diagrams of top views of conventional omnidirectional base station antenna systems with 2T2R and 4T4R configurations, respectively.

[0031] FIG. 3A shows a structural schematic diagram of a conventional feed network having X feed ports and 1 RF port.

[0032] FIG. 3B shows a structural schematic diagram of a feed network having X feed ports and N RF ports according to an example of the present disclosure.

[0033] FIG. 4A shows a schematic diagram of an antenna array in an omnidirectional antenna system with four antenna arrays, according to examples of the present disclosure.

[0034] FIG. 4B and FIG. 4C respectively show a single-layer structural schematic diagram and a top view schematic diagram of the antenna array shown in FIG. 4A.

[0035] FIG. 5 shows a top view schematic diagram of the single-layer structure of an omnidirectional antenna system with four antenna arrays according to an example of the present disclosure.

[0036] FIG. 6 shows a schematic diagram of the connection of the feed network used for the omnidirectional antenna system shown in FIG. 5, according to an example of the present disclosure. [0037] FIG. 7A and FIG. 7B respectively show the port radiation patterns and precoding patterns under the TM4 mode achieved when the omnidirectional antenna system shown in FIG. 5 is configured with the feed network shown in FIG. 6.

[0038] FIG. 8 shows a schematic diagram of the connection of the feed network used for the omnidirectional antenna system shown in FIG. 5, according to another example of the present disclosure.

[0039] FIG. 9A and FIG. 9B respectively show the port radiation patterns and precoding patterns under the TM4 mode achieved when the omnidirectional antenna system shown in FIG. 5 is configured with the feed network shown in FIG. 8.

[0040] FIG. 10 shows a table of the final phase differences formed at each antenna port as a result of setting up the feed network shown in FIG. 8 while taking into account the feed connection method of the radiating elements.

[0041] FIG. 11 A and FIG. 1 IB respectively show the port radiation patterns and precoding patterns under the TM4 mode achieved when the omnidirectional antenna system shown in FIG. 5 is configured with the feed network shown in FIG. 8 and preset with the phase differences shown in FIG. 10.

[0042] FIG. 12A to FIG. 12B show schematic diagrams of the feed connection method used to set the phase differences shown in FIG. 10, according to examples of the present disclosure.

[0043] FIG. 13A shows a schematic diagram of an antenna array in an omnidirectional antenna system with three antenna arrays, according to examples of the present disclosure.

[0044] FIG. 13B and FIG. 13C respectively show a single-layer structural schematic diagram and a top view schematic diagram of the antenna array shown in FIG. 13 A.

[0045] FIG. 14 shows a top view schematic diagram of the single-layer structure of the omnidirectional antenna system with three antenna arrays, according to yet another example of the present disclosure.

[0046] FIG. 15A shows a schematic diagram of the connection of the feed network used for the omnidirectional antenna system shown in FIG. 14, according to yet another example of the present disclosure. [0047] FIG. 15B shows a table of the final phase differences formed at each antenna port as a result of setting up the feed network shown in FIG. 15A while taking into account the feed connection method of the radiating elements.

[0048] FIG. 16 shows a schematic diagram of the feeding method for the omnidirectional antenna system with four antenna arrays, according to examples of the present disclosure.

[0049] FIG. 17 shows a schematic diagram of the feeding method for the omnidirectional antenna system with three antenna arrays, according to examples of the present disclosure.

[0050] It should be noted that in the embodiments described below, the same reference signs are sometimes used across different attached drawings to denote the same parts or parts with similar functions, and repeated descriptions thereof are omitted. In some cases, similar labels and letters are used to denote similar items. Therefore, once an item is defined in one attached drawing, there is no need for further discussion in subsequent attached drawings.

[0051] For ease of understanding, the position, dimension, and range of each structure shown in the attached drawings and the like sometimes do not represent the actual position, dimension, and range. Therefore, the present disclosure is not limited to the positions, dimensions, and ranges disclosed in the attached drawings and the like.

DETAILED DESCRIPTION

[0052] Various exemplary examples of the present disclosure will be described in detail below by referencing the attached drawings. It should be noted that: unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values of components and steps set forth in these examples do not limit the scope of the present disclosure.

[0053] The following description of at least one exemplary example is actually only illustrative, and in no way serves as any limitation to the present disclosure and its application or use. In other words, the structure and method herein are shown in an exemplary manner to illustrate different examples of the structure and method in the present disclosure. However, those skilled in the art will understand that they only illustrate exemplary ways of implementing the present disclosure, rather than exhaustive ways. In addition, the attached drawings are not necessarily drawn to scale, and some features may be enlarged to show details of specific components. [0054] In addition, the technologies, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be regarded as part of the Specification.

[0055] In all examples shown and discussed herein, any specific value should be construed as merely exemplary value and not as limiting value. Therefore, other examples of the exemplary example may have different values.

[0056] FIG. 2A and FIG. 2B are top views of omnidirectional base station antenna systems in conventional 2-transmit/2 -receive (2T2R) and 4-transmit/4-receive (4T4R) configurations, respectively; In general, MEMO functionality may be implemented in base station antenna systems designed to achieve omnidirectional or quasi-omnidirectional radiation patterns. It should be understood that the radiating elements used in an omnidirectional antenna may include dual -polarized radiating elements or a single-polarized radiating element; ±45° polarization or V-H polarization may be adopted for the dual-polarized antenna elements. In the following examples, ±45° dual-polarized radiating elements are mainly used as examples, which include a first feed network for a first polarization direction (such as +45°) and a second feed network for a second polarization direction (such as -45°). Specifically, due to the symmetry or correspondence of the two sets of feed networks, to avoid redundancy, descriptions will often be provided only for the feed network of one polarization direction, and it is understood that the other polarization direction may be similarly configured.

[0057] As shown in FIG. 2A, a conventional 2T2R device simultaneously feeds ports #1 to #4, which are connected to four antenna arrays in symmetrical arrangement, wherein each antenna array may comprise a column of dual-polarized radiating elements configured to form a single antenna beam in each polarization direction within a 90° sector in the azimuth plane, which may thereby be used to implement MEMO communication per antenna beam. Similarly, in the conventional 4T4R configuration as shown in FIG. 2B, ports #1 to #8 are fed simultaneously, and they are connected to four antenna arrays in a symmetrical arrangement, with each antenna array comprising two columns of dual-polarized radiating elements. Compared to the 2T2R scheme in FIG. 2A, the 4T4R scheme in FIG. 2B, while achieving the effect of doubling the transceiver ports and thus supporting higher data throughput, also requires a larger antenna size and a more complex component configuration, which increases costs significantly. Considering the limitations of the antenna mounting space and wind load requirements, a technical solution that simply doubles the number of components will encounter many difficulties.

[0058] Based on this, the present disclosure provides a base station antenna that achieves omnidirectional radiation patterns based on an improved feed network without significantly increasing the overall size of the antenna. First, refer to FIG. 3A which shows conventional single polarization 4x1 feed network 310. for The feed network 310 comprises an RF port 3101 #1 and feed ports 3102 #1 to #4, where the feed ports 3102 are connected to the corresponding antenna arrays to feed the radiating elements. The feed network 310 also includes one or more power dividers 3103 (such as RF power dividers, etc.). In one non-limiting example, the feed network 310 should comprise at least one power divider connected to the RF port 3101 and two power dividers connected to the feed ports 3102, thereby distributing and delivering the RF signals received by the RF port 3101 to the corresponding four feed ports of the antenna arrays.

[0059] Further, to transmit RF signals to more than 4 feed ports, such as when the number "X" is 8, the feed network 310 may be configured with a three-layer power divider structure, such that RF signals from the RF port 3101 #1 are divided three times into 8 RF signals of equal power, which are then outputted to 8 antenna arrays accordingly. Alternatively or additionally, for a single polarization direction, to achieve a feed network for inputting signals via N RF ports greater than 1, such as when N is 2, two sets of feed networks 310 may be arranged as shown in FIG. 3A, in other words repeating the preceding complete set of feed assembly such that RF signals are inputted via RF ports #1 and #2, respectively. In the case where the antenna array comprises dual -polarized radiating elements, four sets of feed networks 310 (two sets per polarization arrangement) are required, thereby achieving a 4T4R communication configuration. It should be understood that in FIG. 3 A, if it is desired to double the number of RF ports, such as from 1 to 2, at least twice as much space would needed for the feed network section to accommodate the duplicate set of feed components, i.e., an undesired increase in size.

[0060] FIG. 3B shows an XxN feed network 320 according to an example embodiment of the present disclosure. The feed network components between RF ports 3201 #1 to #N and feed ports 3202 #1 to #X comprise a 90-degree hybrid coupler 3204 connected to the RF port 3201. Depending on the base attributes of the 90-degree hybrid coupler 3204, it may be used to combine two input signals and divide the input signals into two output signals having a phase difference of 90 degrees while maintaining a high degree of isolation between the two. In other words, the 90-degree hybrid coupler 3204 provides twice as many RF ports (3201) as conventional power dividers without significantly increasing the size of the component. As such, the feed network 320 should comprise at least N/2 90-degree hybrid couplers 3204 when N RF ports greater than 1 need to be provided. It should be understood that FIG. 3B is only one nonlimiting example of a feed network 320. The actual feed network 320 may comprise a structure with more than two layers of components, and/or may comprise only a plurality of 90-degree hybrid couplers connected to each other in one or more ways. Additionally or alternatively, the feed network 320 may also comprise a plurality of power dividers 3203.

[0061] Next, refer to FIG. 4A to FIG. 4C, which respectively show a schematic diagram of an omnidirectional antenna system 40 with four antenna arrays according to an example of the present disclosure, a schematic diagram of the single-layer structure 410 of the antenna arrays, and a top view schematic diagram of the omnidirectional antenna system. Generally, to achieve an omnidirectional or quasi -omnidirectional radiation pattern, a symmetrical four-sided structure is adopted for the antenna system 40, with X being 4 in the aforementioned feed network 320. FIG. 4 A shows an antenna system (where the radome is not shown) that comprises a plurality of columns of radiating elements on the exterior surface of the reflector 420, wherein the reflector 420 has the shape of a regular prism or an approximately regular prism, with its sides composed of reflector plates of the same size, while the number of sides of the base polygon is set depending on the number and positions of the antenna arrays of the desired arrangement. It should be understood that “regular prism” here refers to the reflector 420 having multiple reflector plates as the sides of a regular prism, wherein these reflector plates may form a short connection between each other at the mounting position or form an open circuit based on an insulating structure. The “approximate” in “approximately regular prism” here means that the reflector 420 is mainly composed of sides with a prismatic shape serving as reflector plates; in actual use or installation, it does not have a base and the sides may form flanges with a certain angle and width between the edges and the center of the sides, making it not a regular prism in the geometric sense; however, in this field, it primarily describes that the reflector 420 preferably has a centrally symmetrical shape that facilitates symmetry of the omnidirectional radiation pattern. [0062] With specific reference to FIG. 4 A, each antenna array is distributed on the outer surface of the reflector 420 in a centrally symmetrical position relative to the central axis of the reflector 420. In one non-limiting example, the number of sides of the reflector 420 may be equal to the number of antenna arrays desired to be mounted, wherein each antenna array is arranged with a column of radiating elements on each side, for example, three columns of radiating elements are arranged on the sides of a regular triangular prism, four columns of radiating elements are arranged on the sides of a regular quadrilateral prism, and six columns of radiating elements are arranged on the sides of a regular hexagonal prism, etc. However, as the number of sides of the reflector 420 increases, the reflector plate that makes up each side may be limited in size, thereby increasing the overall design difficulty of the omnidirectional antenna system. Alternatively, a scheme in which two columns of radiating elements are arranged on each side may also be adopted for each antenna array, for example, eight columns of radiating elements on the sides of a regular quadrilateral prism, six columns of radiating elements on the sides of a regular triangular prism, etc. In one example of the antenna array shown in FIG. 4A, four antenna arrays are arranged on the four side reflector plates of the reflector 420, with each antenna array comprising a column of five radiating elements (e g. 4100). It will be understood that the radiating elements included in each antenna array are not limited to a specific number, but are determined based on product design requirements.

[0063] Next, refer to FIG. 4B, which shows a perspective schematic diagram of a singlelayer structure 410 in the omnidirectional antenna system 40. The antenna system 40 may be divided into a plurality of single-layer structures based on the number of radiating elements included in each of the antenna arrays according to a plane perpendicular to the central axis of the reflector 420. FIG. 4B shows the single-layer structure 410 in which the radiating elements 4100 reside. In one non-limiting example, the dual -polarized radiating elements 4100 have a first polarization direction 4101 of -45° and a second polarization direction 4102 of +45°. As shown in FIG. 4B, the radiating elements 4100 are connected to the reflector 420 via a stalk 4101, wherein the stalk 4101 may comprise, for example, four stalks connected to different radiating arms of the radiating elements 4100. Further shown in conjunction with FIG. 4C are two stalks 4101-1 and 4101-2 respectively connected to different polarization directions, which can be seen from the top view (the other two stalks are not shown), thereby achieving feeding in two polarization directions. [0064] Refer to FIG. 5, which shows a schematic diagram of the single-layer structure 410 of the omnidirectional antenna system 40 with four antenna arrays according to an example of the present disclosure. Specifically, the radome 401 of the antenna system may have centrally symmetrically shaped sides, such as a circular bottom profile as shown in FIG. 5 when the radome 401 is cylindrical. That is, the radome 401 may have a cylindrical or prismatic shape. The four antenna arrays are a first, a second, a third, and a fourth antenna array, which are embodied in the single-layer structure 410 as four radiating elements disposed annularly along the inner wall of the radome 401 and arranged at an angle of 90 degrees to each other. Reference may be made to FIG. 16, which shows the spatial relationship of the four radiating elements in the single-layer structure 410. In a single polarization direction, for example, these four radiating elements each correspond to four ports 4110 (denoted as Ai, A2, A3 and A4) of the antenna array, which are connected in one-to-one correspondence to the feed ports 4310 of the feed network 430 shown in FIG. 6, wherein these four feed ports are also denoted as Ai, A2, A3 and A4 for the convenience of description.

[0065] Next, refer to FIG. 6, which shows a schematic diagram of the connection of the feed network 430 used for the omnidirectional antenna system 40 shown in FIG. 5, according to an example of the present disclosure. The feed network 430 is configured to have four feed ports 4310 and two RF ports 4320 (denoted as Pi and P2). That is, for the X*N feed network shown in FIG. 3B, X is 4 and N is 2 in the example shown in FIG. 6. Specifically, the feed network 430 comprises a 90-degree hybrid coupler 4304 and two power dividers, denoted as a first power divider 4303 and a second power divider 4305. In one non-limiting example, the feed network 430 may separately feed two RF communication signals of the same amplitude to the 90-degree hybrid coupler 4304 via the two RF ports 4320, as well as separately feed the four feed ports 4310 via the two-way power dividers 4303 and 4305. Therein, ports Ai and A2 correspond to the power divider 4303 and ports A3 and A4 correspond to the power divider 4305. In other words, as can be seen in conjunction with FIG. 5, the first antenna array and the adjacent second antenna array in the 360-degree annular direction of the radome 401 are connected to the first power divider 4303, while the third antenna array and the fourth antenna array are connected to the second power divider 4305. The phase of the signal input at RF port Pi and transmitted to the feed ports Ai and A2 is 0°, while the phase of the signal input at port Pi and transmitted to the feed ports A3 and A4 is -90°; in addition, the signal input at port P2 and transmitted to the feed ports Ai and A2 is -90°, while the phase of the signal input at port P2 and transmitted to the feed ports A3 and A4 is 0°.

[0066] The resulting radiation patterns are shown in FIG. 7A and FIG. 7B. FIG. 7A and FIG. 7B respectively show the port radiation patterns and precoding patterns under the TM4 mode achieved when the omnidirectional antenna system 40 shown in FIG. 5 is configured with the feed network 430 shown in FIG. 6. Specifically, FIG. 7A shows a radiation pattern at the output of each port at a frequency of 2.2 GHz, wherein the radiation patterns formed by the two signals input by Pi and P2 are such that one is at a peak position and the other is approximately at a null position, with the two compensating for each other to essentially achieve a quasi- omnidirectional pattern. Referring to FIG. 7B at the same time, upon further examination of the precoding pattern generated by the antenna system, it can be seen that the [0, 90] and [0, -90] patterns satisfy relative orthogonality characteristics within a certain phase range while ignoring certain errors. For example, the position of the null in the [0, 90] pattern approximately corresponds to the peak in the [0, -90] pattern, which is conducive to maximizing MIMO communication performance.

[0067] Alternatively, FIG. 8 shows a schematic diagram of the connection of the feed network 430 used for the omnidirectional antenna system 40 shown in FIG. 5, according to another example of the present disclosure. In another non-limiting example, the phase difference of the output signals from the various ports may be set by changing the manner in which the feed network 430 is connected to the various antenna arrays. The same reference numerals in FIG. 8 as in FIG. 6 denote the same components and will not be described again; the main differences are that ports Ai and A3 correspond to the power divider 4303 and ports A2 and A4 correspond to the power divider 4305. In other words, as can be seen in conjunction with FIG. 5, for the first to fourth antenna arrays corresponding to the four ports, the first antenna array and the third antenna array, positioned at an angle of 180 degrees with respect to the central axis of the radome 401, are arranged to be fed by the first power divider 4303, and the second antenna array and the fourth antenna array are arranged to be fed by the second power divider 4305. This setup of the connection relationship changes the phase relationship between the input RF signals of the second antenna array and the third antenna array, thereby causing the radiation patterns to change. The phase of the signal input at RF port Pi and transmitted to the feed ports Ai and A3 is 0°, while the phase of the signal input at port Pi and transmitted to the feed ports A2 and A4 is - 90°; in addition, the signal input at port P2 and transmitted to the feed ports Ai and A3 is -90°, while the phase of the signal input at port P2 and transmitted to the feed ports A2 and A4 is 0°.

[0068] The corresponding changes in the radiation patterns can be seen in FIG. 9A and FIG. 9B. FIG. 9A and FIG. 9B respectively show the port radiation patterns and precoding patterns under the TM4 mode achieved when the omnidirectional antenna system 40 shown in FIG. 5 is configured with the feed network 430 shown in FIG. 8. As shown in FIG. 9 A, at a frequency of 2.2 GHz, the connection method in FIG. 8 is also capable of achieving a relatively ideal quasi-omnidirectional radiation pattern. Examining the precoding patterns in FIG. 9B, all four patterns have distinct peaks and nulls and their tendency to vary with each other, and it is possible to satisfy approximate orthogonal characteristics within a certain range.

[0069] Additionally or alternatively, the phase difference of the radiating elements 4100 may be further set to optimize the radiating patterns. In yet another non-limiting example, the initial phase of the various antenna ports may be preset by adjusting the feed connection method of the radiating elements 4100. FIG. 10 shows a table of the final phase differences formed at each antenna port as a result of setting up the feed network shown in FIG. 8 while taking into account the feed connection method of the radiating elements. Specifically, the respective initial phases between the ports Ai and A4 as well as between A2 and A3 are set to be equal, and the ports A2 and A3 are set to have a phase difference of -180° with respect to Ai and A4. Based on this, coupled with the 90° phase difference generated between the two RF signals generated through the feed network 320 based on the inherent attributes of the 90-degree hybrid coupler, the phases of the signals input at port Pi and transmitted to the feed ports A2, A3 and A4 are - 270°, -180° and -90° respectively; in addition, the phases of the signals input at port P2 and transmitted to the feed ports Ai, A2, A3 and A4 are -90°, -180°, -270° and 0°, respectively.

[0070] The resulting radiation patterns can be seen in FIG. 11 A and FIG. 1 IB. FIG. 11 A and FIG. 1 IB respectively show the port radiation patterns and precoding patterns under the TM4 mode achieved when the omnidirectional antenna system shown 40 in FIG. 5 is configured with the feed network 430 shown in FIG. 8 and preset with the phase differences shown in FIG. 10. As shown in FIG. 11 A, at a frequency of 2.2 GHz, the radiation pattern realized at each port can form a quasi-omnidirectional pattern. The radiation patterns formed by the two signals input at ports Pi and P2 are such that when one is at a peak position, the other is approximately at a null, with the two compensating for each other. In addition, as also seen in FIG. 1 IB, more desirable orthogonal characteristics may be achieved between the [0, 0] and [0, 180] patterns as well as between the [0, 90] and [0, -90] patterns, with each of the patterns having obviously clear peaks and nulls, and with the peaks of one group corresponding to the positions of the nulls in the other. In other words, the precoding patterns in the TM4 mode are also more favorable, thus enabling the maximization of MIMO performance.

[0071] Additionally, regarding how the phase differences shown in FIG. 10 may be set, that is, setting a phase of -180° for ports A2 and A3, refer to FIG. 12A and FIG. 12B for details. FIG. 12A to FIG. 12B show schematic diagrams of the feed connection method used to set the phase differences shown in FIG. 10, according to examples of the present disclosure. FIG. 12A shows a front view of the single-layer structure 410 from the direction of the first antenna array corresponding to the port Ai, and FIG. 12B shows a front view of the single-layer structure 410 from the direction of the second antenna array, that is, FIG. 12B is equivalent to the viewing angle achieved by rotating FIG. 12A 90° toward the left side of the paper along the central axis of the antenna system. Therein, with respect to the +45° polarization direction of each of the radiating elements (refer to the second polarization direction 4102 in FIG. 4B), the direction of the feed points in the radiating elements in the first antenna array corresponding to the port Ai and the fourth antenna array corresponding to A4 is set to be opposite the direction of the feed points in the radiating elements in the second antenna array corresponding to the port A2 and in the third antenna array corresponding to A3, i.e., the phase corresponding to the ports Ai and A4 shown in FIG. 2A is 0°, while the phase corresponding to the ports A2 and A3 is -180°. Alternatively, the phase differences may also be achieved by altering the length difference between the feed cables of the second antenna array and the third antenna array relative to the feed cables of the first antenna array and the fourth antenna array. As a result, the phase difference between the two sets of ports may be achieved in a relatively simple manner while keeping the circuit structure basically unchanged, and thus the radiation patterns required by the omnidirectional antenna may be optimized in a relatively compact component space.

[0072] It should be understood that the omnidirectional antenna system of the present disclosure may be implemented by a plurality of directional antenna arrays (the aforementioned X) arranged in a spatially symmetrical manner, wherein FIG. 4A illustrates a case where X is 4, while in practice X may also be set to other numbers, for example, X may also be 3. Next, refer to FIG. 13 A to FIG. 13C, which respectively show a schematic diagram of an omnidirectional antenna system 60 with three antenna arrays according to another example of the present disclosure, a schematic diagram of a single-layer structure 610 of the antenna arrays, and a top view schematic diagram of the omnidirectional antenna system. Similarly, the antenna system 60 comprises a reflector 620 having three sides, which are composed of three reflector plates of the same size, and the bottom is an approximately equilateral triangle. First, second, and third antenna arrays are respectively arranged on the sides of the reflector 620, wherein, for example, the first antenna array comprises radiating elements 6100. Further, the radiating elements 6100 are connected to the reflector 620 via a stalk 6101, wherein the stalk 6101 may comprise, for example, four stalks connected to different radiating arms of the radiating elements 6100. FIG. 13C shows, when the radiating elements 6100 are dual-polarized radiating elements, stalks 6101- 1 and 6101-2 (the other two stalks are not shown) that are separately connected to different polarization directions for feeding, as can be seen from the top view.

[0073] Next, refer to FIG. 14, which shows a top view schematic diagram of the singlelayer structure 610 of the omnidirectional antenna system with three antenna arrays, according to yet another example of the present disclosure. The antenna system comprises a cylindrical radome and three antenna arrays, presented in the single-layer structure 610 as three radiating elements corresponding to the first to third antenna array, and connected to respective antenna ports 6110 (respectively denoted as Ai, A2, and A3). Further, FIG. 15A shows a schematic diagram of the connection of two feed networks 630 for the omnidirectional antenna system shown in FIG. 14. The feed networks 630 are configured to have three feed ports 6310 (also denoted as Ai, A2 and A3 corresponding to the antenna ports 6110 for brevity) and two RF ports 6320 (denoted as Pi and P2). That is, for the X*N feed network shown in FIG. 3B, X is 3 and N is 2 in the example shown in FIG. 15A. Specifically, the feed network 630 comprises a 90- degree hybrid coupler 6304 and a power divider (denoted as a third power divider 6303) that function similarly to the corresponding components of the feed network 430 in FIG. 6. The main difference is that due to the odd number of feeding ports 6310, not all of them can be connected to the output ports of the two-way power divider. At least one port (e.g. port A3 in FIG. 15 A) may be directly connected to one output port of the 90-degree hybrid coupler 6304. Further, the 90-degree hybrid coupler 6320 may be configured such that the output power of the first output port thereof is twice the output power of the second output port thereof; and when the first output port is then connected to the third power divider 6303 for two-way division, three signals of equal power are obtained and are separately outputted to the corresponding antenna arrays.

[0074] Alternatively, FIG. 15B shows a table of the final phase differences formed at each antenna port as a result of setting up the feed network shown in FIG. 15A while taking into account the feed connection method of the radiating elements. In one non-limiting example, the initial phase of the various antenna ports may be preset by adjusting the feed connection method of the radiating elements 6110. Specifically, the initial phases between the ports Ai and A2 are set to be equal, and the port A3 is set to have a phase difference of -180° with respect to Ai and A2. Then, with the phase of the transmitted signals inputted from the RF port Pi to the feed port Ai being 0°, the phases of the transmitted signals inputted from Pi to the feed ports A2 and A3 are 0° and -270°; and the phases of the transmitted signals inputted from P2to the feed ports Ai, A2 and A3 are -90°, -90° and -180°, respectively. From the distribution of the output phases of the three ports, it appears that setting specific phase differences has no obvious impact on improving the orthogonal characteristics of precoding patterns under the TM4 mode. It should be understood that this means that for a base station antenna system with three antenna arrays, whether or not phase differences are preset, the aforementioned orthogonal characteristics can still be achieved to some extent, thus facilitating MIMO performance optimization. In other words, in the three-sided omnidirectional base station antenna system 60, the use of a feed network containing a 90-degree hybrid coupler is primarily intended to achieve the effect of doubling the RF ports in a compact space.

[0075] Next, refer to FIG. 16, which shows a schematic diagram of a feeding method for an omnidirectional antenna system having four antenna arrays as shown in FIG. 4A. To facilitate the presentation of the relationships between components, the three-dimensional structure of the antenna system 40 is unfolded and drawn on the same plane, comprising the first to fourth antenna arrays, specifically comprising four columns of dual-polarized radiating elements of five per column; and two sets of feed networks 430, separately denoted as 430-1 and 430-2. Therein, for one polarization direction, such as the -45° direction, stalks corresponding to that polarization direction in a column of radiating elements are sequentially connected and thereby connected via the same antenna port to one of the feed ports 4310 of the feed network 430-1, thereby connecting the four antenna arrays sequentially to the four feed ports. Similarly, for another polarization direction, i.e., the +45° direction, another set of stalks in the column of radiating elements is sequentially connected and thereby connected via the same antenna port to one of the feed ports of the feed network 430-2. As a result, the omnidirectional base station antenna system 40, with its structure of four antenna arrays, is equipped with four RF ports for MIMO communication, thereby achieving a 4T4R communication configuration. Additionally, when each of the first to fourth antenna arrays comprises two columns of radiating elements (refer to FIG. 2B for the hardware structure), i.e., when the single-layer structure 410 comprises eight radiating elements, a setup similar to that of the feed network 430 may be configured with 8 RF ports and 4 feed networks, thus achieving an 8T8R configuration.

[0076] Alternatively, FIG. 17 shows a schematic diagram of a feed method of an omnidirectional antenna system having three antenna arrays. Similar to the configuration of FIG. 16, the omnidirectional base station antenna system 60 comprises first to third antenna arrays and two feed networks 630-1 and 630-2. Therein, for the -45° direction, stalks corresponding to that polarization direction in a column of radiating elements are sequentially connected and thereby connected via the same antenna port to one of the feed ports 6310 of the feed network 630-1; and the +45° direction is similarly configured. As a result, the antenna system 60, with its structure of three antenna arrays, is equipped with four RF ports for MIMO communication, achieving a 4T4R communication configuration. Similarly, when each of the first to third antenna arrays comprises two columns of radiating elements, an 8T8R communication configuration may also be achieved by adjusting the components of the feed network to increase the number of ports.

[0077] It should be understood that the omnidirectional base station antenna described in the examples of the present disclosure may be designed with more arrays than just the three- sided and four-sided antenna arrays shown in FIG. 16 and FIG. 17, depending on actual needs. Consequently, it is also possible to achieve a 16T16R or other MIMO communication configuration. That is, for the aforementioned X antenna arrays of the omnidirectional base station antenna, X may be a numerical value other than 3 or 4; and considering that setting only one antenna array is more applicable to directional antennas in order to achieve an omnidirectional radiation pattern, X should be at least 2 or greater. On the other hand, for base station antennas, when there are size limitations on the outer diameter, X affects the number of sides of the reflector plate of each side. If X is too large, the reflector on a single side will be too narrow, which is not conducive to the mounting of radiating elements. In other words, the numerical value of X should be determined based on a combination of exterior size constraints and MIMO communication requirements, among other things. Tn addition, considering the inherent characteristics of a 90-degree hybrid coupler, the number of RF ports in the feeding network, i.e., the total input ports of the 90-degree hybrid coupler denoted as N, should not exceed X to achieve a reasonable feeding circuit structure.

[0078] The terms “left”, “right”, “front”, “rear”, “top”, “bottom”, “upper”, “lower”, “high”, “low” in the Specification and Claims, if present, are used for descriptive purposes and not necessarily used to describe constant relative positions. It should be understood that the terms used in this way are interchangeable under appropriate circumstances, so that the examples of the present disclosure described herein, for example, can operate on other orientations that differ from those orientations shown herein or otherwise described. For example, when the device in the attached drawing is turned upside down, features that were originally described as “above” other features can now be described as “below” other features. The device may also be oriented by other means (rotated by 90 degrees or at other locations), and at this time, a relative spatial relation will be explained accordingly.

[0079] In the Specification and Claims, when an element is referred to as being “above” another element, “attached” to another element, “connected” to another element, “coupled” to another element, or “contacting” another element, the element may be directly above another element, directly attached to another element, directly connected to another element, directly coupled to another element, or directly contacting another element, or there may be one or more intermediate elements. In contrast, if an element is described “directly” “above” another element, “directly attached” to another element, “directly connected” to another element, “directly coupled” to another element or “directly contacting” another element, there will be no intermediate elements. In the Specification and claims, a feature that is arranged “adjacent” to another feature, may denote that a feature has a part that overlaps an adjacent feature or a part located above or below the adjacent feature.

[0080] As used herein, the word “exemplary” means “serving as an example, instance, or illustration” rather than as a “model” to be copied exactly. Any realization method described exemplarily herein is not necessarily interpreted as being preferable or advantageous over other realization methods. Moreover, the present disclosure is not limited by any expressed or implied theory given in the technical field, background art, summary of the invention, or specific implementation methods. [0081] As used herein, the word “basically” means comprising any minor changes caused by design or manufacturing defects, device or component tolerances, environmental influences, and/or other factors. The word “basically” also allows the gap from the perfect or ideal situation due to parasitic effects, noise, and other practical considerations that may be present in the actual realization.

[0082] In addition, for reference purposes only, “first”, “second” and similar terms may also be used herein, and thus are not intended to be limitative. For example, unless the context clearly indicates, the words “first”, “second” and other such numerical words involving structures or elements do not imply a sequence or order.

[0083] It should also be understood that when the term “include/comprise” is used in this text, it indicates the presence of the specified feature, entirety, step, operation, unit and/or component, but does not exclude the presence or addition of one or more other features, entireties, steps, operations, units and/or components and/or combinations thereof.

[0084] In the present disclosure, the term “provide” is used in a broad sense to cover all ways of obtaining an object, so “providing an object” includes but is not limited to “purchase”, “preparation/manufacturing”, “arrangement/setting”, “installation/assembly”, and/or “order” of the object, etc.

[0085] As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. The terms used herein are only for the purpose of describing specific examples, and are not intended to limit the present disclosure. As used herein, the singular forms “a”, “an” and “the” are also intended to include the plural forms, unless the context clearly dictates otherwise.

[0086] Those skilled in the art should realize that the boundaries between the above operations are merely illustrative. A plurality of operations can be combined into a single operation, which may be distributed in the additional operation, and the operations can be executed at least partially overlapping in time. Also, alternative examples may include a plurality of instances of specific operations, and the order of operations may be changed in other various examples. However, other modifications, changes and substitutions are also possible. Aspects and elements of all examples disclosed above may be combined in any manner and/or in conjunction with aspects or elements of other examples to provide a plurality of additional examples. Therefore, the Specification and attached drawings hereof should be regarded as illustrative rather than limitative.

Claims

Claims:

1. A base station antenna, wherein it comprises: a radome;

X antenna arrays configured to be distributed annularly along the inner wall of the radome, wherein X > 2; a feed network configured to have N RF ports and X feed ports connected to the X antenna arrays, with N < X, wherein the feed network comprises at least one 90-degree hybrid coupler connected to the N RF ports, and wherein the phase difference between the X antenna arrays is set by arranging the connection relationship between the X antenna arrays and the feed network to achieve quasi- omnidirectional antenna patterns.

2. The base station antenna according to Claim 1, wherein each of the X antenna arrays comprises dual -polarized antenna elements, wherein the feed network comprises a first feed network for feeding a first polarization direction and a second feed network for feeding a second polarization direction.

3. The base station antenna according to Claim 1, wherein when X is 4, the first antenna array and the third antenna array, positioned at an angle of 180 degrees with respect to a central axis of the radome, are arranged to be fed by a first power divider, and the second antenna array and the fourth antenna array are arranged to be fed by a second power divider.

4. The base station antenna according to Claim 3, wherein the feeding method of the radiating elements is configured such that an initial phase of the first antenna array and the fourth antenna array is a first phase, and an initial phase of the second antenna array and the third antenna array is a second phase, and wherein a phase difference between the second phase and the first phase is -180 degrees.

5. The base station antenna according to Claim 4, wherein for the same polarization direction, the feed points of the second antenna array and the third antenna array are oriented opposite to those of the first antenna array and the fourth antenna array to achieve the aforementioned phase difference.

6. The base station antenna according to Claim 4, wherein for the same polarization direction, the phase difference is achieved by altering the length difference between the feed cables of the second antenna array and the third antenna array relative to the feed cables of the first antenna array and the fourth antenna array.

7. The base station antenna according to Claim 1, wherein when X is 3, the feed network comprises a power divider and a 90-degree hybrid coupler, wherein an output power of a first output port of the 90-degree hybrid coupler is twice an output power of the second output port of the 90-degree hybrid coupler, and the first output port is connected to the power divider to feed the first antenna array and the second antenna array, and the second output port is coupled to the third antenna array.

8. The base station antenna according to any of Claims 1-7, wherein the radome has a cylindrical or prismatic shape.

9. The base station antenna according to any of Claims 1-7, further comprising a reflector, wherein X antenna arrays are arranged on the reflector, and the reflector has the shape of a regular prism or an approximately regular prism.

10. The base station antenna according to Claim 9, wherein the X antenna arrays are distributed on the outer surface of the reflector in a centrally symmetrical position relative to the central axis of the reflector.

11. The base station antenna according to Claim 9, wherein when X is 6, the shape of the reflector may be a regular triangular prism or a regular hexagonal prism, wherein when the reflector has the shape of a regular triangular prism, two columns of radiating elements are arranged on each side of the reflector; and when the reflector has the shape of a regular hexagonal prism, one column of radiating elements is arranged on each side of the reflector.

12. The base station antenna according to Claim 9, wherein when X is 8, the shape of the reflector may be a regular quadrilateral prism or a regular octagonal prism, wherein when the reflector has the shape of a regular quadrilateral prism, two columns of radiating elements are arranged on each side of the reflector, and when the reflector has the shape of a regular octagonal prism, one column of radiating elements is arranged on each side of the reflector.

13. A MIMO base station antenna, comprising: a radome;

X antenna arrays configured to be distributed annularly along the inner wall of the radome; a feed network configured to have X feed ports connected to the X antenna arrays, wherein the feed network comprises one or more 90-degree hybrid couplers to achieve a doubled number of ports for MIMO communication.

14. The base station antenna according to Claim 13, wherein the feed network has N RF ports that are coupled to input ports of the one or more 90-degree hybrid couplers.

15. The base station antenna according to Claim 14, wherein the X antenna arrays comprise dual -polarized antenna elements, and the base station antenna is implemented with a communication configuration of 2N transmitting antennas and 2N receiving antennas based on the feed network.

16. The base station antenna according to Claim 15, wherein a 4T4R configuration may be achieved when N is 2.

17. The base station antenna according to Claim 15, wherein an 8T8R configuration may be achieved when N is 4.