Patent Application
20210296760
This patent application claims priority to and the benefit of Chinese Patent Application Serial Number 202010198924.2 filed Mar. 20, 2020, the content of which is hereby incorporated by reference as if recited in full herein.
The present invention relates to communications systems and, more particularly, to base station antennas.
In a cellular communication system, a geographic area is divided into a series of regions, which are called “cells” that are served by corresponding base stations. Each base station may include one or more antennas that are configured to provide two-way radio frequency (“RF”) communication with mobile users in the cell served by the base station. In many cases, each cell is divided into “sectors”. In a common configuration, a hexagonal cell is divided into three 120° sectors in the azimuth plane, and each sector is served by one or more base station antennas whose azimuth half-power beam width (“HPBW”) is about 65°. Generally, the base station antenna is mounted on a tower, with the radiation pattern (also referred to herein as the “antenna beam”) produced by the base station antenna pointing outwards. Base station antennas are usually implemented as linear or planar phased arrays of radiating elements.
Embodiments of the present invention are directed to base station antennas.
A first aspect of this invention is to provide a base station antenna that includes: a reflector that is configured to provide a ground plane; a first radiating element array including at least one first cross-polarized radiating element that is arranged on the reflector; and a first parasitic element array including first through third parasitic element pairs that respectively extend substantially parallel to a first longitudinal axis of the at least one first cross-polarized radiating element and are respectively coupled to the reflector. Each of the first through third parasitic element pairs includes a pair of parasitic elements that are arranged substantially symmetrically on both sides of the first longitudinal axis, and distances from the first through third parasitic element pairs respectively to the first longitudinal axis increase sequentially. Projections of any two of the first parasitic element pair, the second parasitic element pair, the third parasitic element pair, and the at least one first cross-polarized radiating element on the first longitudinal axis at least partly overlap.
The base station antenna can comprise slant 45 degree radiating elements and parasitic elements can extend at an angle of 45 degrees with respect to a dipole radiator of a respective radiating element. The parasitic elements can be horizontal or vertical parasitics.
Other aspects of the present invention provide a base station antenna that includes a reflector that is configured to provide a ground plane and a radiating element array including horizontally adjacent first and second columns of cross-polarized radiating elements that are respectively arranged on the reflector substantially parallel to a longitudinal axis of the base station antenna. The first column includes a first radiating element, the second column includes a second radiating element. The base station antenna also includes a parasitic element array including first through fifth parasitic elements between the first and second columns that each extend substantially parallel to the longitudinal axis, extend forwardly from the reflector, and are coupled to the reflector, and the first through fifth parasitic elements are sequentially spaced apart from each other in a horizontal direction. Projections of any two of the first parasitic element, the second parasitic element, the third parasitic element, and the first radiating element on the longitudinal axis at least partly overlap, and projections of any two of the third parasitic element, the fourth parasitic element, the fifth parasitic element, and the second radiating element on the longitudinal axis at least partly overlap.
Another aspect of the present invention is directed to a base station antenna that includes: a reflector that is configured to provide a ground plane; a radiating element that is arranged on the reflector, the radiating element including a slant −45 degree dipole radiator with respect to a longitudinal axis of the radiating element and a slant +45 degree dipole radiator with respect to the longitudinal axis; and a parasitic element array including first through third parasitic element pairs that respectively extend substantially parallel to the longitudinal axis and are respectively coupled to the reflector. Each of the first through third parasitic element pairs includes a pair of parasitic elements that are arranged substantially symmetrically on both sides of the longitudinal axis, and distances from the first through third parasitic element pairs respectively to the longitudinal axis increase sequentially, wherein projections of any two of the first parasitic element pair, the second parasitic element pair, the third parasitic element pair, and the radiating element on the longitudinal axis at least partly overlap.
Another aspect of this invention is to provide a base station antenna that includes: a reflector that is configured to provide a ground plane; a cross-polarized radiating element that is arranged on the reflector; and a parasitic element array that includes first through third parasitic element pairs that respectively extend substantially parallel to a horizontal axis of the radiating element and are respectively coupled to the reflector. Each of the first through third parasitic element pairs includes a pair of parasitic elements that are arranged substantially symmetrically on both sides of the horizontal axis, and distances from the first through third parasitic element pairs respectively to the horizontal axis increase sequentially. Projections of any two of the first parasitic element pair, the second parasitic element pair, the third parasitic element pair, and the radiating element on the horizontal axis at least partly overlap.
Yet another aspect is directed to a base station antenna that includes: a reflector that is configured to provide a ground plane; a radiating element that is arranged on the reflector, the radiating element including a slant −45 degree dipole radiator with respect to a horizontal axis of the radiating element and a slant +45 degree dipole radiator with respect to the horizontal axis; and a parasitic element array including first through third parasitic element pairs that respectively extend substantially parallel to the horizontal axis and are respectively coupled to the reflector. Each of the first through third parasitic element pairs includes a pair of parasitic elements that are arranged substantially symmetrically on both sides of the horizontal axis, and distances from the first through third parasitic element pairs respectively to the horizontal axis increase sequentially. Projections of any two of the first parasitic element pair, the second parasitic element pair, the third parasitic element pair, and the radiating element on the horizontal axis at least partly overlap.
Other features of the present invention and advantages thereof will become explicit by means of the following detailed descriptions of exemplary embodiments of the present invention with reference to the drawings.
The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.
Note that, in some cases the same elements or elements having similar functions are denoted by the same reference numerals in different drawings, and description of such elements is not repeated. In some cases, similar reference numerals and letters are used to refer to similar elements, and thus once an element is defined in one figure, it need not be further discussed for following figures.
In order to facilitate understanding, the position, size, range, or the like of each structure illustrated in the drawings may not be drawn to scale. Thus, the invention is not necessarily limited to the position, size, range, or the like as disclosed in the drawings.
The present invention will be described with reference to the accompanying drawings, which show a number of example embodiments thereof. It should be understood, however, that the present invention can be embodied in many different ways, and is not limited to the embodiments described below. Rather, the embodiments described below are intended to make the disclosure of the present invention more complete and fully convey the scope of the present invention to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in any way to provide many additional embodiments.
The terminology used herein is for the purpose of describing particular embodiments, but is not intended to limit the scope of the present invention. All terms (including technical terms and scientific terms) used herein have meanings commonly understood by those skilled in the art unless otherwise defined. For the sake of brevity and/or clarity, well-known functions or structures may be not described in detail.
Herein, when an element is described as located “on” “attached” to, “connected” to, “coupled” to or “in contact with” another element, etc., the element can be directly located on, attached to, connected to, coupled to or in contact with the other element, or there may be one or more intervening elements present. In contrast, when an element is described as “directly” located “on”, “directly attached” to, “directly connected” to, “directly coupled” to or “in direct contact with” another element, there are no intervening elements present. In the description, references that a first element is arranged “adjacent” a second element can mean that the first element has a part that overlaps the second element or a part that is located above or below the second element.
Herein, the foregoing description may refer to elements or nodes or features being “connected” or “coupled” together. As used herein, unless expressly stated otherwise, “connected” means that one element/node/feature is electrically, mechanically, logically or otherwise directly joined to (or directly communicates with) another element/node/feature. Likewise, unless expressly stated otherwise, “coupled” means that one element/node/feature may be mechanically, electrically, logically or otherwise joined to another element/node/feature in either a direct or indirect manner to permit interaction even though the two features may not be directly connected. That is, “coupled” is intended to encompass both direct and indirect joining of elements or other features, including connection with one or more intervening elements.
Herein, terms such as “upper”, “lower”, “left”, “right”, “front”, “rear”, “high”, “low” may be used to describe the spatial relationship between different elements as they are shown in the drawings. It should be understood that in addition to orientations shown in the drawings, the above terms may also encompass different orientations of the device during use or operation. For example, when the device in the drawings is inverted, a first feature that was described as being “below” a second feature can be then described as being “above” the second feature. The device may be oriented otherwise (rotated 90 degrees or at other orientation), and the relative spatial relationship between the features will be correspondingly interpreted.
Herein, the term “A or B” used through the specification refers to “A and B” and “A or B” rather than meaning that A and B are exclusive, unless otherwise specified. The term “exemplary”, as used herein, means “serving as an example, instance, or illustration”, rather than as a “model” that would be exactly duplicated. Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the detailed description.
Herein, the term “substantially”, is intended to encompass any slight variations due to design or manufacturing imperfections, device or component tolerances, environmental effects and/or other factors. The term “substantially” also allows for variation from a perfect or ideal case due to parasitic effects, noise, and other practical considerations that may be present in an actual implementation.
Herein, certain terminology, such as the terms “first”, “second” and the like, may also be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, the terms “first”, “second” and other such numerical terms referring to structures or elements do not imply a sequence or order unless clearly indicated by the context.
Further, it should be noted that, the terms “comprise”, “include”, “have” and any other variants, as used herein, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.
It should be noted that when multiple identical or similar elements are provided herein, two-part reference numbers (e.g., parasitic element 141-1) may be used to label them in the drawings. These elements may be individually referred to herein by all of their reference numbers (e.g., parasitic elements 141-1 and 141-2) and may be collectively referred to by the first part of their reference numbers (e.g., parasitic element pair 141).
The base station antennas according to some embodiments of the present invention each include first through third parasitic element pairs that respectively extend substantially parallel to the longitudinal or horizontal axis of a cross-polarized radiating element, and are respectively coupled to the reflector. Each parasitic element pair includes a pair of parasitic elements that are arranged substantially symmetrically on both sides of the axis. Distances from the first through third parasitic element pairs respectively to the axis increase sequentially. Projections of any two of the first parasitic element pair, the second parasitic element pair, the third parasitic element pair, and the cross-polarized radiating element on the axis at least partly overlap.
The cross-polarized radiating element includes two radiators that are arranged to be orthogonal to each other, for example, a slant −45 degree dipole radiator and a slant +45 degree dipole radiator with respect to the axis. For example, when the +45 degree dipole radiator is being operated, in the non-ideal case, a relatively small amount of electromagnetic radiation in the −45 degree direction is generated. By adjusting the sizes and arrangements of the parasitic elements near the cross-polarized radiating element, it is possible to increase the electromagnetic radiation in the +45 degree direction and reduce the electromagnetic radiation in the −45 degree direction when the +45 degree dipole radiator is being operated. Therefore, the base station antennas according to the embodiments of the present invention can provide an improved cross polarization ratio (“CPR”) over sector.
The base station antenna according to an embodiment of the present invention may be, for example, a non-miniaturized antenna, an antenna with a high operating frequency band (for example, 2.3 to 3.8 GHz frequency band), or a MIMO antenna. For example in a MIMO antenna, the spacing between two adjacent columns of radiating elements may be about a wavelength corresponding to a center frequency of an operating frequency band of the radiating elements. Due to the relatively large physical spacing, the isolation between the two columns may usually meet the requirement (e.g., −30 dB˜−40 dB), and it may not be necessary to add additional parasitic elements between the adjacent two columns so as to improve the isolation between the two columns. In the event that additional isolation is necessary, the spacing between the two columns is large enough to arrange the above-mentioned parasitic elements, so at least a part of the parasitic elements in the base station antenna according to the embodiments of the present invention may be easily arranged between the two columns.
Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings.
The parasitic element array 140 includes three parasitic element pairs 141 through 143 that respectively extend substantially parallel to the axis 120 and are respectively coupled to the reflector 110. Distances from the three pairs 141 through 143 to the axis 120 increase sequentially. Each of the parasitic element pairs 141 through 143 include a pair of parasitic elements 141-1 and 141-2, 142-1 and 142-2, or 143-1 and 143-2. Each pair of parasitic elements 141-1 and 141-2, 142-1 and 142-2, or 143-1 and 143-2 are arranged substantially symmetrically on both sides of the axis 120. In the illustrated embodiment, the projection of each of the parasitic element pairs 141 through 143 on the axis 120 extends over the entire projection of the radiating element 131 on the axis 120. It will be appreciated that in other embodiments, projections of any two of the parasitic element pair 141, the parasitic element pair 142, the parasitic element pair 143, and the radiating element 131 on the axis 120 at least partly overlap.
A distance from a parasitic element pair to an axis and a projection of an element on the axis will be described with reference to
Referring to
Referring to
Referring to
In the foregoing, the embodiments in which parasitic elements are provided on both sides of the longitudinal axis or on both sides of the horizontal axis of the radiating element have been described in conjunction with the drawings. It will be appreciated that in other embodiments, parasitic elements may be provided both on both sides of the longitudinal axis and on both sides of the horizontal axis of the radiating element.
It should be noted that, a longitudinal axis herein refers to a virtual axis (no physical structure used as an axis is necessary) extending along the length direction (also referred to as the vertical direction) of the base station antenna, and a horizontal axis refers to a virtual axis extending along the width direction (also referred to as the horizontal direction) of the base station antenna. For simplicity, the longitudinal axes and/or the horizontal axes are not shown in some drawings, and it will be appreciated that such virtual axes exist in the embodiments depicted in these drawings. Although the longitudinal axis 120 shown in
Each parasitic element in the parasitic element array includes a conductor portion extending substantially forwardly from the reflector. The conductor portion is substantially perpendicular to the reflector. A pair of the conductor portions of each of the parasitic element pairs extend forwardly substantially the same length from the reflector. The effect of the parasitic element array on the CPR over sector may be tuned by adjusting the length of the conductor portion of each parasitic element extending forwardly from the reflector. In some embodiments, the length of the conductor portion extending forwardly from the reflector is smaller than the length of the corresponding radiating element extending forwardly from the reflector, so as not to affect the width of the antenna beam. In some embodiments, for example when the parasitic element is relatively near the corresponding radiating element, the length of the conductor portion extending forwardly from the reflector is less than or substantially equal to half the length of the corresponding radiating element extending forwardly from the reflector. For example, for a base station antenna with an operating frequency band of 2.3 to 3.8 GHz, the length of the radiating element extending forwardly from the reflector (that is, the distance between the radiating arm of the radiating element and the reflector) may be approximately a quarter of the wavelength corresponding to the center frequency of the operating frequency band, such as 25 mm. In these embodiments, the length of the conductor portion extending forwardly from the reflector may be less than or substantially equal to 12.5 mm. In addition, the effect of the parasitic element array on the CPR over sector may be tuned by adjusting the distance between the conductor portions of two parasitic elements. In some embodiments, on a side of the radiating element, the distances between the conductor portions of every two adjacent parasitic elements may be substantially constant. In some embodiments, on a side of the radiating element, the distances between the conductor portions of every two adjacent parasitic elements may be varied.
Referring to
Referring to
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In an embodiment, the reflector has a forwardly-extending flange on an edge that is on a side of a longitudinal axis of the base station antenna, for example so as to improve the radiation pattern of the antenna. The flange may have a common portion with a parasitic element mentioned above, for example, may serve as the parasitic element. As shown in
In the illustrated embodiment, the projection of each parasitic element on the axis 420 extends over the entire projection of the radiating element array 430 on the axis 420. It will be appreciated that in other embodiments, projections of any two of the parasitic element pair 441, the parasitic element pair 442, the parasitic element pair 443, and the at least one radiating element 431 in the first column 430-1 on the axis 420-1 at least partly overlap, and projections of any two of the parasitic element pair 444, the parasitic element pair 445, the parasitic element pair 446, and the at least one radiating element 432 in the second column 430-2 on the axis 420-2 at least partly overlap.
Each parasitic element in the parasitic element array may include a first portion that extends forwardly from the reflector. The first portion includes a first conductor that is substantially perpendicular to the reflector. In an embodiment, the first portion that includes the first conductor may be formed of a metal plate (sheet). In another embodiment, the first portion may be formed of a Printed Circuit Board (PCB), and the first conductor is the conductor printed on the PCB. In an embodiment, the first portion may be configured as a protrusion of the reflector that extends forwardly. In another embodiment, the first portion may be soldered to the reflector so as to be mounted and galvanically connected to the reflector. In other embodiments, the first portion may be mounted or coupled to the reflector in other ways.
Referring to
The parasitic element may further include a second portion that extends substantially parallel to the reflector. The second portion includes a second conductor. As shown in
As shown in
In an embodiment, as shown in
In some embodiments, the second portion of a parasitic element may also be mechanically connected to the rear section of the first portion of an adjacent parasitic element. In an embodiment, the two adjacent parasitic elements are configured as an integral piece having a generally U-shaped horizontal section and may be formed for example by stamping a metal plate. As shown in
Although some specific embodiments of the present invention have been described in detail with examples, it should be understood by a person skilled in the art that the above examples are only intended to be illustrative but not to limit the scope of the present invention. The embodiments disclosed herein can be combined arbitrarily with each other, without departing from the scope and spirit of the present invention. It should be understood by a person skilled in the art that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202010198924.2 | Mar 2020 | CN | national |
