WO2026019555A1

WO2026019555A1 - Base station antenna

Info

Publication number: WO2026019555A1
Application number: PCT/US2025/035837
Authority: WO
Inventors: Jianpeng LU; Hangsheng Wen; Guiyu SUN; Fei Li; Yuanpeng REN; Changfu Chen
Original assignee: Outdoor Wireless Networks LLC
Current assignee: Outdoor Wireless Networks LLC
Priority date: 2024-07-17
Filing date: 2025-06-30
Publication date: 2026-01-22
Anticipated expiration: 2027-01-17
Also published as: CN121367046A

Abstract

A base station antenna comprises a radome; a reflector; radiation element arrays mounted on respective faces of the reflector; and radiation pattern modulating elements configured to be mounted between the radome and the reflector and used to optimize a roundness of a radiation pattern achieved by the radiation element arrays.

Description

BASE STATION ANTENNA

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to Chinese Patent Application No. 202410956007.4, filed July 17, 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 a plurality of phased arrays of radiation elements, wherein the radiation elements are arranged in one or a plurality of 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 a plurality of 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 a plurality of 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 radiation 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 radiation elements. Beamforming arrays are capable of generating antenna beams that have a narrowed beamwidth in, for example, a horizontal or “azimuthal” plane, 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 MIMO radio device and used to send/receive one of a plurality of data streams. In fact, since orthogonal polarizations tend to be highly uncorrelated, radiation elements in MIMO arrays are often implemented as dual-polarized radiation 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 radiation elements in the column, and the second port is connected to a second polarization radiator of the radiation elements in the column). This technique can effectively reduce the number of columns of radiation 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; a reflector; an radiation element array mounted on respective faces of the reflector; and radiation pattern modulating elements configured to be mounted between the radome and the reflector and used to optimize a roundness of a radiation pattern achieved by radiation element arrays.

[0009] According to a second aspect of the present disclosure, an omnidirectional radiation base station antenna is provided, wherein it comprises: a tubular reflector configured to have at least a first face to a third face; a first radiation element array to a third radiation element array mounted on the respective first face to third face of the tubular reflector; and radiation pattern modulating elements configured to comprise metamaterials MTMs periodically distributed in correspondence with the first radiation element array to the third radiation element array.

[0010] According to a third aspect of the present disclosure, an omnidirectional radiation base station antenna is provided, wherein it comprises: a radome; a tubular reflector configured to have at least a first face to a third face; a first radiation element array to a third radiation element array mounted on the respective first face to third face of the tubular reflector; and radiation pattern modulating elements configured to comprise metal traces periodically distributed on an inner side of the radome in correspondence with a junction of two adjacent faces in the first face to the third face.

[0011] According to a fourth aspect of the present disclosure, an omnidirectional radiation slot cavity antenna is provided, wherein it comprises: a reflector; radiation element arrays mounted on respective faces of the reflector; radiation pattern modulating elements configured to comprise metamaterials MTMs distributed periodically, wherein the MTMs are configured to have traces having a same shape and size on surfaces of its two sides.

[0012] An advantage of examples according to the present disclosure is that an omnidirectional base station antenna that can optimize a roundness of a radiation pattern is provided, which compensates for a radiation null by using radiation pattern modulating elements having a periodic structure to modulate a phase difference between a plurality of radiation elements and/or a radiation intensity.

[0013] Another advantage of examples according to the present disclosure is that for an omnidirectional base station antenna comprising high-frequency radiation elements and low- frequency radiation elements, a radiation pattern of a high frequency band can be optimized with almost no effect on a low frequency band; and for an omnidirectional base station antenna having horizontal/vertical (H/V: ) polarization, a roundness of a radiation pattern of the vertical polarization can be optimized with almost no effect on a radiation pattern of the horizontal polarization.

[0014] It should be appreciated that the above advantages do 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. [0015] 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

[0016] 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:

[0017] Fig. 1 is a structural schematic diagram of a conventional base station.

[0018] Fig. 2A and Fig. 2B are a perspective view and a top view, respectively, of a conventional base station antenna comprising high-frequency radiation elements.

[0019] Fig. 2C shows a radiation pattern of the base station antenna in Fig. 2A and Fig. 2B.

[0020] Fig. 3A and Fig. 3B are a perspective view and a top view, respectively, of a conventional base station antenna comprising high-frequency radiation elements and low- frequency radiation elements.

[0021] Fig. 3C shows a radiation pattern of the base station antenna in Fig. 3 A and Fig. 3B.

[0022] Fig. 4 is a schematic diagram of a radiation pattern of a base station antenna according to an example of the present disclosure.

[0023] Fig. 5A shows a schematic front view of a radiation pattern modulating element of a base station antenna according to an example of the present disclosure.

[0024] Fig. 5B to Fig. 5C are a perspective view and a top view, respectively, of a radiation pattern modulating element in Fig. 5A mounted in a base station antenna according to an example of the present disclosure.

[0025] Fig. 5D shows a radiation pattern of the base station antenna in Fig. 5B and Fig.

5C. [0026] Fig. 6A and Fig. 6B are a perspective view and a top view, respectively, of a base station antenna comprising high-frequency radiation elements and low-frequency radiation elements according to an example of the present disclosure.

[0027] Fig. 7A is a schematic diagram of a radiation pattern modulating element of a base station antenna according to another example of the present disclosure.

[0028] Fig. 7B and Fig. 7C are a perspective view and a top view, respectively, of a radiation pattern modulating element in Fig. 7A mounted in a base station antenna according to another example of the present disclosure.

[0029] Fig. 7D shows a radiation pattern of the base station antenna in Fig. 7B and Fig. 7C.

[0030] Fig. 8A and Fig. 8B are a perspective view and a top view, respectively, of a base station antenna comprising high-frequency radiation elements according to another example of the present disclosure.

[0031] Fig. 9A and Fig. 9B are a perspective view and a top view, respectively, of a base station antenna comprising high-frequency radiation elements and low-frequency radiation elements according to yet another example of the present disclosure.

[0032] Fig. 10A is a schematic diagram of a radiation pattern modulating element of a base station antenna according to an alternative example of the present disclosure.

[0033] Fig. 10B and Fig. 10C are a perspective view and a top view, respectively, of the radiation pattern modulating element in Fig. 10A mounted in a base station antenna according to an alternative example of the present disclosure.

[0034] Fig. HA and Fig. 1 IB show a radiation pattern of the base station antenna in Fig. 10B and Fig. 10C in a vertical polarization direction and a horizontal polarization direction, respectively.

[0035] It should be noted that in the examples 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.

[0036] 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

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] It should be noted that when a plurality of same or similar elements are provided below, reference signs composed of numbers in two parts may be used to label them in the attached drawings, such as MTM (metamaterial) 400-1, MTM 400-2, etc. These elements may be referred to herein individually by their respective full reference signs; and may be referred to collectively by a first part common in their reference signs (e.g., MTM 400) when no distinction is needed between them.

[0042] In general, a base station antenna system for achieving an omnidirectional or quasi -omni directional radiation pattern may be combined to provide an MIMO function, which can form a radiation pattern with a higher roundness by arranging a plurality of directional antenna arrays in a spatially symmetrical manner, and mainly consists of a reflector, a plurality of radiation element arrays and a radome. It should be understood that the radiation elements used in an omnidirectional antenna may include dual-polarized radiation elements or a singlepolarized radiation element; ±45° polarization or V-H polarization may be adopted for the dualpolarized antenna elements. In the following examples, ±45° dual -polarized radiation 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.

[0043] Reference is made to Fig. 2A and Fig. 2B, which are a perspective view and a top view, respectively, of a conventional omnidirectional base station antenna comprising high- frequency radiation elements. The base station antenna includes three radiation element arrays and a reflector and is configured to support 4-transmit/4-receive (4T4R) communications. Specifically, as shown in Fig. 2B, in a radome 100, radiation element arrays 300 are mounted on respective faces 201, 202 and 203 of three faces of the tubular reflector 200, and each radiation antenna array 300 includes two columns of radiation elements, for example, the first radiation element array comprises radiation elements in column #1 and column #4, and the second radiation antenna array comprises radiation elements in column #2 and column #5, etc. The radiation elements in column #1, column #2 and column #3 are fed by a set of feed networks, and the radiation elements in column #4, column #5 and column #6 are fed by another set of feed networks, where one column and another column in column #1, column #2 and column #3 differ 120 degrees relative to an axis of the reflector 200, and one column and another column in column #4, column #5 and column #6 differ 120 degrees relative to the axis of the reflector 200. Further, the radiation antenna arrays 300 are composed of dual-polarized radiation elements, thereby enabling 4T4R communications. It will be understood that although the tubular reflector 200 has symmetry in space, the symmetry of column #1, column #2 and column #3 may be offset relative to side faces of the reflector 200 due to the fact that mounting positions of column #1, column #2 and column #3 on each respective face are unable to be located in the center of that face (column #4, column #5 and column #6 are also similar). As shown in Fig. 2C, a more significant nulls are present in the radiation pattern of the base station antenna in Fig. 2A and Fig. 2B at 1 .7-1.9 GHz, for example, three deep nulls where the magnitude of the RF signal is nearly 30db below the peak magnitude, making the roundness of the radiation pattern poor.

[0044] Alternatively, reference is made to Fig. 3A and Fig. 3B, which are a perspective view and a top view, respectively, of another conventional omnidirectional base station antenna comprising high-frequency radiation elements and low-frequency radiation elements. The base station antenna of Fig. 3 A and Fig. 3B includes three radiation element arrays and a reflector, and differs from the base station antenna in Fig. 2A in that each radiation element array 300 comprises three columns of radiation elements, for example, the first radiation antenna array includes radiation elements in column #1, column #4 and column #7, etc., where radiation elements in column #1 and column #4 are listed as high-frequency radiation elements and radiation elements in column #7 are listed as low-frequency radiation elements. Similarly, as shown in Fig. 3C, the radiation pattern of the base station antenna in Fig. 3 A and Fig. 3B similarly results in a deep null of about -15db, affecting a roundness of the omnidirectional radiation pattern.

[0045] Pursuant to embodiments of the present invention, base station antennas are provided that include radiation pattern modulating elements that may improve the roundness of the omnidirectional radiation pattern without significantly affecting the size of the antenna Reference is first made to Fig. 4, which is a schematic diagram of a radiation pattern of a base station antenna according to an example embodiment of the present disclosure. Generally, in case that the mounting positions are symmetrical, distances of radio frequency signals output by, for example, radiation elements in column #7 mounted in the center of the first face 201 and radiation elements in column #8 mounted in the center of the second face 202 shown in Fig. 3B reaching junctions of two faces of the reflector in the space in correspondence with sectors. For a set of radiation elements with mounting positions being asymmetrical compared to the center of each face of the reflector, as shown in Fig. 4, taking radiation elements in column #1, column #2 and column #3 fed by the same set of feed network as an example, due to the offset of their mounting positions relative to the centers of the two faces of the reflector 200, the distances of the radiation elements in column #1 on the first face 201 and the radiation elements in column #3 on the third face 203 reaching a point 10 in space are not equal, and radio frequency signals emitted by the radiation elements in column #1 and column #3 will produce a phase difference when reaching the point 10, that is, the phase of column #1 reaching the point 10 is ahead of the phase of column #3 reaching point 10. It will be understood that magnitudes of the signals of column #1 and the signals of column #3 may also have offset upon reaching the point 10, but the magnitude difference is smaller than the phase difference. Because of the phase difference, the radio frequency signals emitted by the radiation elements in column #1 and column #3, respectively, will not constructively combine completely (and may destructively combine). Consequently, significant radiation nulls may be present in the radiation pattern in a region near junctions of two sectors. The radiation pattern modulating elements according to embodiments of the present invention compensate for the aforementioned phase difference, thereby improving the roundness of the radiation pattern.

[0046] In a non-limiting example, reference is made to Fig. 5A to Fig. 5C, in which Fig. 5B to Fig. 5C are a perspective view and a top view, respectively, of the radiation pattern modulating elements in Fig. 5A mounted in a base station antenna according to an example of the present disclosure. Fig. 5A shows one cell of metamaterials (MTMs) as radiation pattern modulating elements, which may be designed in a shape such as a square, wherein a substrate and an annular trace mounted on the substrate are included. In one non-limiting example, the substrate of the MTMs may be made of a material having a dielectric constant of about 3.5, and may have a low-resistance high-pass filtering effect on the radio frequency signals. Fig. 5B shows a mounting position of MTM 400 in an omnidirectional base station antenna, for example, MTM 400-1, 400-2 and 400-3 may be periodically distributed between the reflector and the radiation element arrays 300 and configured to be mounted in correspondence with a first radiation element array to a third radiation element array, respectively. In one non-limiting example, as shown in Fig. 5C, the MTM 400-1 may include a plurality of MTM cells in two columns as shown in Fig. 5 A, and there may be an angle of bending along an inner side of the reflective shield 100 between the two columns of MTM cells. Based on the characteristics of the MTM 400, a signal phase of column #1 is delayed to be similar to a signal phase of column #3, thereby obtaining an improved radiation pattern in Fig. 5D, wherein a radiation null is no less than - 15db, and its roundness is improved.

[0047] Alternatively, Fig. 6A and Fig. 6B are a perspective view and a top view, respectively, of a base station antenna comprising high-frequency radiation elements and low- frequency radiation elements according to an example of the present disclosure. That is, when the base station antenna shown in Fig. 3B is provided with the MTM 400 shown in Fig. 5A, the roundness of its omnidirectional radiation pattern may similarly be improved.

[0048] In another non-limiting example, reference is made to Fig. 7A to Fig. 7C, in which Fig. 7B to Fig. 7C are a perspective view and a top view, respectively, of a radiation pattern modulating element of Fig. 7A mounted in another base station antenna according to an example of the present disclosure. Fig. 7A shows a set of metal traces 500 as a radiation pattern modulating element, which can be designed as a plurality of traces at uniform spacing, forming a parasitic element at a junction of the base station antenna, and wherein a parasitic current produces secondary radiation, thereby providing compensation for magnitudes. In one nonlimiting example, there may be 5 metal traces in one set. Fig. 7B shows mounting positions of metal traces 500 in an omnidirectional base station antenna, for example, the metal traces 500-1, 500-2 and 500-3 may be periodically distributed between the reflective shield 100 and the radiation element arrays 300 and configured to be mounted on an inner side of the radome 100 in correspondence with a junction of two adjacent faces in the first face 201 to the third face 203, respectively. As shown in Fig. 7C, the three sets of metal traces 500 are periodically distributed 120 degrees apart from each other on the inner side of the reflective shield 100. Based on the characteristics of the metal traces 500, the phase difference between signals of column #1 and column #3 is reduced, thereby obtaining an improved radiation pattern in Fig. 7D, wherein a radiation null is no less than - 15db, and its roundness is improved.

[0049] Alternatively, Fig. 8A and Fig. 8B are a perspective view and a top view, respectively, of a base station antenna comprising high-frequency radiation elements according to another example of the present disclosure. That is, when the metal traces 500 in Fig. 7A are mounted in the base station antenna shown in Fig. 2B, the roundness of its omnidirectional radiation pattern may similarly be optimized.

[0050] In yet another non-limiting example, reference is made to Fig. 9A and Fig. 9B, which are a perspective view and a top view, respectively, of a base station antenna comprising high frequency radiation elements and low frequency radiation elements according to yet another example of the present disclosure. The radiation pattern modulating elements may include MTMs and metal traces mounted simultaneously between the reflective shield 100 and the radiation element arrays 300, thereby superimposing the technical effects of the examples shown

-l i in Fig. 6B and Fig. 7B, achieving the modulation of the phase difference, and producing secondary radiation to improve the radiation null in the omnidirectional radiation pattern.

[0051] Further, the base station antenna system for achieving an omnidirectional or quasi-omnidirectional radiation pattern may also be achieved by a slot cavity antenna. A conventional slot cavity antenna includes an upper media substrate, a lower media substrate and their corresponding metal layers. Due to the inherent properties caused by the structure, a roundness of a radiation pattern in its vertical polarization direction is worse than that in the horizontal polarization direction. With reference to Fig. 10A to Fig. 10C, a slot cavity antenna as an alternative example of the present disclosure is provided, where Fig. 10B and Fig. 10C are a perspective view and a top view, respectively, of a radiation pattern modulating element 610 in Fig. 10A mounted in the base station antenna 600. In one non-limiting example, Fig. 10A shows a cell as a radiation pattern modulating element 610, which may be designed as a periodically distributed MTM 610-2, and has traces having a same shape and size on surfaces of its two sides. Fig. 10B and Fig. 10C show a mounting position of the radiation pattern modulating element 610, for example, 5 element cells as shown in Fig. 10A may be included and mounted in a surrounding mode in correspondence with a slot of the slot cavity antenna 600.

[0052] Further, Fig. 11 A and Fig. 1 IB show a radiation pattern of the base station antenna in Fig. 10B and Fig. 10C in the vertical polarization direction and the horizontal polarization direction, respectively, wherein a comparison of patterns of the base station antenna including or not including the radiation pattern modulating element 610 is shown. Based on the characteristics of the radiation pattern modulating element 610, as shown in Fig. 11A, the roundness of the radiation pattern of the base station antenna 600 in the vertical polarization direction is significantly improved; and for the horizontal polarization direction, as shown in Fig. 1 IB, the characteristics of the original omnidirectional pattern are not significantly affected. Based on this, the radiation pattern modulating element 610 is able to provide an improved roundness of the radiation pattern for the slot cavity antenna 600.

[0053] 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.

[0054] 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 a plurality of 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.

[0055] 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.

[0056] 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.

[0057] 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. [0058] 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.

[0059] 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.

[0060] 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.

[0061] 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, comprising: a radome; a reflector; radiation element arrays mounted on respective faces of the reflector; and radiation pattern modulating elements configured to be mounted between the radome and the reflector and configured to improve a roundness of a radiation pattern achieved by radiation element arrays.

2. The base station antenna according to Claim 1, wherein the reflector comprises a tubular reflector having at least a first face to a third face; and the radiation element arrays comprise a first radiation element array to a third radiation element array mounted on the respective first face to third face of the tubular reflector.

3. The base station antenna according to Claim 2, wherein each of the radiation element arrays in the first radiation element array to the third radiation element array comprises at least two columns of radiation elements.

4. The base station antenna according to Claim 3, wherein the radiation pattern modulating elements comprise periodically-distributed metamaterials (MTMs).

5. The base station antenna according to Claim 4, wherein the MTMs are configured to be mounted in correspondence with the first radiation element array to the third radiation element array, respectively.

6. The base station antenna according to Claim 4, wherein the MTMs are configured to at least partially compensate for a difference in a phase of a first radio frequency signal that is emitted by a first column of radiation elements mounted on the first face and a phase of a second radio frequency signal that is emitted by a second column of radiation elements mounted on the second face when the first and second radio frequency signals reach a same point in space, wherein the first column and the second column differ 120 degrees relative to an axis of the reflector.

7. The base station antenna according to Claim 3, wherein each of the radiation element arrays in the first radiation element array to the third radiation element array comprises at least two columns of high-frequency radiation elements and at least one column of low- frequency radiation elements.

8. The base station antenna according to Claim 3 or 7, wherein the radiation pattern modulating elements comprise periodically-distributed metal traces.

9. The base station antenna according to Claim 8, wherein the metal traces are configured to be mounted on an inner side of the radome in correspondence with a junction of two adjacent faces in the first face to the third face, respectively.

10. The base station antenna according to Claim 8, wherein the metal traces are configured to reduce a phase difference of a first column of radiation elements mounted on the first face and a second column of radiation elements mounted on the second face reaching a same point in space, wherein the first column and the second column differ 120 degrees relative to an axis of the reflector.

11. The base station antenna according to Claim 10, wherein the metal traces are further configured to produce secondary radiation.

12. The base station antenna according to Claim 3 or 7, wherein the radiation pattern modulating elements comprise periodically-distributed metamaterials MTMs and metal traces.

13. The base station antenna according to Claim 1, wherein the base station antenna is a horizontal/vertical polarized slot cavity antenna; and the radiation pattern modulating elements comprise periodically-distributed metamaterials MTMs, wherein the MTMs are configured to have traces having a same shape and size on surfaces of its two sides.

14. The base station antenna according to Claim 13, wherein the radiation pattern modulating elements are configured to be mounted around a slot side of the slot cavity antenna.

15. An omnidirectional radiation base station antenna, comprising: a tubular reflector configured to have at least a first face to a third face; a first radiation element array to a third radiation element array mounted on the respective first face to third face of the tubular reflector; and radiation pattern modulating elements configured to comprise metamaterials MTMs periodically distributed in correspondence with the first radiation element array to the third radiation element array.

16. The base station antenna according to Claim 15, wherein the MTMs are configured to compensate for a phase difference of a first column of radiation elements mounted on the first face and a second column of radiation elements mounted on the second face reaching a same point in space, wherein the first column and the second column differ 120 degrees relative to an axis of the reflector.

17. An omnidirectional radiation base station antenna, comprising: a radome; a tubular reflector configured to have at least a first face to a third face; a first radiation element array to a third radiation element array mounted on the respective first face to third face of the tubular reflector; and radiation pattern modulating elements configured to comprise metal traces periodically distributed on an inner side of the radome in correspondence with a junction of two adjacent faces in the first face to the third face.

18. The base station antenna according to Claim 17, wherein the metal traces are configured to reduce a phase difference of a first column of radiation elements mounted on the first face and a second column of radiation elements mounted on the second face reaching a same point in space, wherein the first column and the second column differ 120 degrees relative to the axis of the reflector.

19. An omnidirectional radiation slot cavity antenna, comprising: a reflector; radiation element arrays mounted on respective faces of the reflector; radiation pattern modulating elements configured to comprise periodically distributed metamaterials MTMs, wherein the MTMs are configured to have traces having a same shape and size on surfaces of its two sides.

20. The slot cavity antenna according to Claim 19, wherein the radiation pattern modulating elements are configured to be mounted around a slot side of the slot cavity antenna.