Base station antenna

Abstract

The invention relates to a base station antenna. Provided is a base station antenna, comprising: a reflector; a first radiator located in front of the reflector and configured to operate within a first operating frequency range; the dielectric substrate is located between the first radiator and the reflector, a conductive unit array is arranged on the dielectric substrate, and the dielectric substrate with the conductive unit array forms a phase gradient metasurface (PGM). The PGM is configured to apply a phase gradient to radiation within the first operating frequency range incident on the PGM.

Description

Technical Field

[0001] This disclosure generally relates to the field of antennas, and more specifically, to a base station antenna. Background Technology

[0002] In a typical cellular communication system, a geographical area is divided into a series of areas called "cells," and each cell is served by one or more base stations. Each base station may include baseband equipment, radio equipment, and an antenna, which can be configured to provide two-way radio frequency (RF) communication with fixed and mobile subscribers (who may be referred to as users) geographically located within the cell. In many cases, a cell may be divided into multiple sectors, and each individual antenna provides coverage for its respective sector. Antennas are typically mounted on towers or other raised structures, and the radiated beam ("antenna beam") generated by each antenna is pointed outward to provide service to the corresponding sector.

[0003] Azimuth beamwidth (AZBW) refers to the width of the radiation pattern generated by an antenna in the azimuth plane, typically used to describe the antenna's radiation capability in the horizontal direction. AZBW is generally characterized as the beamwidth (in degrees) of the radiation pattern at a specific power level compared to the peak power level. For example, 3dB AZBW refers to the width (in degrees) of the azimuth plane section passing through the main lobe of the radiation pattern at an elevation angle within 3dB of the peak power level of the radiation pattern. The smaller the AZBW, the more energy the antenna can concentrate in a particular direction. Specifically, a smaller AZBW makes the antenna more directive because the signal is focused more in that specific direction, improving signal strength and quality. In environments with multiple signal sources or noise, a smaller AZBW can effectively reduce unwanted signals or interference from other directions, contributing to improved signal clarity and transmission reliability. Summary of the Invention

[0004] According to one aspect of this disclosure, a base station antenna is provided, comprising: a reflector; a first radiator located in front of the reflector and configured to operate within a first operating frequency range; and a dielectric substrate located between the first radiator and the reflector, on which a conductive element array is disposed. The dielectric substrate having the conductive element array constitutes a phase gradient metasurface (PGM), the PGM being configured to apply a phase gradient to radiation incident on the PGM within the first operating frequency range.

[0005] In some embodiments, the PGM and the reflector are configured to work together to reflect at least 97% of the radiation emitted rearward by the first radiator.

[0006] In some embodiments, the PGM is configured to reflect a first portion of the rearward radiation emitted by the first radiator, and the reflector is configured to reflect a second portion of the rearward radiation emitted by the first radiator, the second portion being transmitted through the PGM.

[0007] In some embodiments, each conductive unit in the conductive unit array includes a conductive trace having a substantially circular outer contour. In some examples, the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of the first operating frequency range. In some examples, each conductive unit includes a substantially square conductive patch disposed within a perimeter defined by the conductive trace segment. In some examples, the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of the first operating frequency range, and the side length of the conductive patch is approximately the same as the outer radius of the conductive trace.

[0008] In some embodiments, the base station antenna includes a second radiator located in front of and closer to the reflector than the conductive element array. The second radiator is configured to operate within a second operating frequency range, which is higher than the first operating frequency range. The PGM is configured to allow radiation within the second operating frequency range to pass through it. In some examples, a choke is provided in the conductive trace. For example, the length of the choke is approximately one-quarter of the wavelength at the center operating frequency of the second operating frequency range.

[0009] In some embodiments, the first radiator includes a first dipole arranged along a first axis, and the conductive element array includes a first plurality of conductive elements arranged along the first axis. In some examples, the dimensions of the first plurality of conductive elements gradually increase in a direction parallel to the first axis. In some examples, the dimensions of the first plurality of conductive elements are the same as each other.

[0010] In some embodiments, the first radiator includes a second dipole arranged along a second axis substantially perpendicular to the first axis. In some examples, the conductive element array includes a second plurality of conductive elements arranged along the second axis. In some examples, the conductive element array does not include conductive elements arranged along the second axis.

[0011] In some embodiments, the base station antenna includes a plurality of first radiators arranged in a single column, each of the plurality of first radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, and a corresponding conductive element array disposed between each of the plurality of first radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis and a second plurality of conductive elements arranged along the second axis.

[0012] In some embodiments, the base station antenna includes a plurality of first radiators arranged in two columns, each of the plurality of first radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, and a corresponding conductive element array disposed between each of the plurality of first radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis but excluding conductive elements arranged along the second axis.

[0013] In some embodiments, the first radiator is located at the front end of a first feed rod extending forward from the reflector, and the conductive element array includes a first sub-array located on a first side of the first feed rod and a second sub-array located on a second side of the first feed rod opposite to the first side. In some examples, the dielectric substrate includes a first dielectric substrate and a second dielectric substrate, the first sub-array is disposed on the first dielectric substrate, the second sub-array is disposed on the second dielectric substrate, and the first feed rod extends through a gap between the first dielectric substrate and the second dielectric substrate. In some examples, the dielectric substrate includes an opening located between the first sub-array and the second sub-array, and the first feed rod extends through the opening. In some examples, the conductive element array includes a conductive element located at the first feed rod, the dielectric substrate includes an opening located in the conductive element, and the first feed rod extends through the opening.

[0014] In some embodiments, the first radiator and the reflector are located at approximately one-quarter of the wavelength at the center operating frequency of the first operating frequency range, and the conductive element array and the reflector are located at approximately one-eighth of the wavelength at the center operating frequency of the first operating frequency range.

[0015] According to another aspect of this disclosure, a base station antenna is provided, comprising: a reflector; a radiator located in front of the reflector; and a dielectric substrate located between the radiator and the reflector, on which a conductive element array is disposed. Each conductive element in the conductive element array includes a conductive trace having a substantially circular outer contour.

[0016] In some embodiments, the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of the radiator's operating frequency range.

[0017] In some embodiments, each conductive unit includes a substantially square conductive patch disposed within a perimeter defined by the conductive trace segment. In some examples, the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of the radiator's operating frequency range, and the side length of the conductive patch is approximately the same as the outer radius of the conductive trace.

[0018] In some embodiments, a choke is provided in the conductive trace. In some examples, the length of the choke is approximately one-quarter of the wavelength at the center operating frequency of another operating frequency range higher than the operating frequency range of the radiator.

[0019] In some embodiments, the radiator includes a first dipole arranged along a first axis, and the conductive element array includes a first plurality of conductive elements arranged along the first axis. In some examples, the dimensions of the first plurality of conductive elements gradually increase in a direction parallel to the first axis. In some examples, the dimensions of the first plurality of conductive elements are the same as each other.

[0020] In some embodiments, the radiator includes a second dipole arranged along a second axis substantially perpendicular to the first axis. In some examples, the conductive element array includes a second plurality of conductive elements arranged along the second axis. In some examples, the conductive element array does not include conductive elements arranged along the second axis.

[0021] In some embodiments, the base station antenna includes a plurality of radiators arranged in a single column, each of the plurality of radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, and a corresponding conductive element array disposed between each of the plurality of radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis and a second plurality of conductive elements arranged along the second axis.

[0022] In some embodiments, the base station antenna includes a plurality of radiators arranged in two columns, each of the plurality of radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, and a corresponding array of conductive elements disposed between each of the plurality of radiators and the reflector, the array of conductive elements including a first plurality of conductive elements arranged along the first axis but excluding conductive elements arranged along the second axis.

[0023] In some embodiments, the radiator is located at the front end of a feed rod extending forward from the reflector, and the conductive element array includes a first sub-array located on a first side of the feed rod and a second sub-array located on a second side of the feed rod opposite to the first side. In some examples, the dielectric substrate includes a first dielectric substrate and a second dielectric substrate, the first sub-array being disposed on the first dielectric substrate, the second sub-array being disposed on the second dielectric substrate, and the feed rod extending through a gap between the first dielectric substrate and the second dielectric substrate. In some examples, the dielectric substrate includes an opening located between the first sub-array and the second sub-array, and the feed rod extending through the opening. In some examples, the conductive element array includes conductive elements located at the feed rod, the dielectric substrate including an opening located in the conductive element, and the feed rod extending through the opening.

[0024] In some embodiments, the radiator and the reflector are located at approximately one-quarter of the wavelength at the center operating frequency of the radiator's operating frequency range, and the conductive element array and the reflector are located at approximately one-eighth of the wavelength at the center operating frequency of the radiator's operating frequency range.

[0025] Other features and advantages of this disclosure will become clearer from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0026] The foregoing and other features and advantages of this disclosure will become clear from the following description of embodiments illustrated in conjunction with the accompanying drawings. The drawings, incorporated herein and forming a part of the specification, are further used to explain the principles of this disclosure and to enable those skilled in the art to make and use it. Wherein:

[0027] Figure 1 A bottom view of a base station antenna according to some embodiments of the present disclosure is schematically depicted;

[0028] Figure 2 An example of a conductive element employed in a phase gradient metasurface in a base station antenna according to some embodiments of the present disclosure is schematically depicted;

[0029] Figure 3 A bottom view of a base station antenna according to some embodiments of the present disclosure is schematically depicted;

[0030] Figure 4 An example of a conductive element employed in a phase gradient metasurface in a base station antenna according to some embodiments of the present disclosure is schematically depicted;

[0031] Figures 5 to 8 Front views of base station antennas according to some embodiments of the present disclosure are schematically depicted respectively;

[0032] Figure 9 and Figure 10 Front views of base station antennas according to some embodiments of the present disclosure are schematically depicted respectively;

[0033] Figure 11 The amplitude and phase of radiation reflected by a phase gradient metasurface and radiation transmitted by a phase gradient metasurface in a base station antenna according to a first exemplary embodiment of the present disclosure are shown as a function of frequency.

[0034] Figure 12 A schematic front view of a base station antenna according to a first comparative example and a base station antenna according to a second exemplary embodiment of the present disclosure is depicted.

[0035] Figure 13 It shows Figure 12 The radiation patterns of the two base station antennas during operation;

[0036] Figure 14 It shows Figure 12 The peak directivity and peak gain of the two base station antennas during operation;

[0037] Figure 15 A schematic front view of a base station antenna according to a second comparative example and a base station antenna according to a third to fifth exemplary embodiment of the present disclosure is depicted.

[0038] Figure 16 A perspective view and a front view of a base station antenna according to a third comparative example and a base station antenna according to a sixth to seventh exemplary embodiment of the present disclosure are schematically depicted.

[0039] Figure 17 It shows Figure 16 The radiation patterns of three base station antennas when the dipoles of two adjacent mid-frequency radiating elements tilted at +45° are activated.

[0040] Figure 18 It shows Figure 16The three-dimensional directivity and gain of three base station antennas when the dipoles of two adjacent mid-frequency radiating elements tilted at +45° are activated;

[0041] Figure 19 It shows Figure 16 The radiation patterns of the two base station antennas when the dipoles tilted at +45° in the low-frequency band radiating element are activated.

[0042] Figure 20 It shows Figure 16 The three-dimensional directivity, gain, 3dB AZBW and 10dB AZBW of the two base station antennas when the dipoles of the low-frequency radiating elements are activated at a +45° tilt.

[0043] Figure 21 It shows Figure 16 The radiation patterns of the two base station antennas when the dipoles tilted at -45° in the low-frequency band radiating element are activated.

[0044] Figure 22 It shows Figure 16 The three-dimensional directivity, gain and 3dB AZBW of the two base station antennas when the dipoles of the low-frequency radiating elements are activated at a -45° tilt.

[0045] Note that in the embodiments described below, the same reference numerals are sometimes used across different figures to denote the same parts or parts with the same function, and repeated descriptions are omitted. In some cases, similar reference numerals and letters are used to denote similar items, so once an item is defined in one figure, it does not need to be discussed further in other figures.

[0046] For ease of understanding, the positions, dimensions, and extents of the structures shown in the accompanying drawings and other materials may not represent actual positions, dimensions, and extents. Therefore, this disclosure is not limited to the positions, dimensions, and extents disclosed in the accompanying drawings and other materials. Detailed Implementation

[0047] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0048] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this disclosure or its application or use. That is, the structures and methods herein are shown in an exemplary manner to illustrate different embodiments of the structures and methods in this disclosure. However, those skilled in the art will understand that they merely illustrate exemplary ways that can be used to implement this disclosure, and not exhaustive ways. Furthermore, the drawings are not necessarily drawn to scale, and some features may be enlarged to show details of specific components.

[0049] In addition, techniques, methods and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods and equipment should be considered part of the specification.

[0050] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0051] In typical cellular base station antenna applications, the low-frequency band (LB) can be the frequency range of 617MHz-960MHz or a portion thereof, and the mid-frequency band (MB) can be the frequency range of 1.7GHz-2.7GHz or a portion thereof. In some cases, higher frequency bands may also be involved, such as the high-frequency band (HB), which may include, for example, the frequency range of 3.3GHz-4.2GHz or a portion thereof.

[0052] The smaller the AZBW (e.g., 3dB AZBW, 10dB AZBW, etc.) exhibited by an antenna, the better its directivity and anti-interference capability. Generally, the AZBW of low-frequency radiating elements is wider than that of mid-frequency radiating elements, which may be due to the following reasons: In terms of radiation wavelength, low-frequency radiating elements have a longer radiation wavelength than mid-frequency radiating elements, resulting in weaker radiation directivity and thus a wider radiation angle range. In terms of antenna design, low-frequency radiating elements have a larger structure than mid-frequency radiating elements, which allows them to radiate energy more uniformly, thus forming a broad radiation pattern. In terms of phase matching, in the low-frequency band, because the phase change of electromagnetic waves is relatively slow, the interference effect of adjacent radiating elements is reduced, resulting in a wider radiation direction; while in the mid-frequency band, the phase change of electromagnetic waves is fast, resulting in stronger directivity. Therefore, it is desirable to reduce the AZBW of the radiating element array in the base station antenna, especially to reduce the AZBW of (one or more) low-frequency band arrays.

[0053] Increasing the width of the antenna's reflector is one way to reduce AZBW, but this obviously increases the antenna's size, making it bulkier and more difficult to install, leading to a significant increase in cost. Two known techniques for reducing AZBW are staggering the radiating elements in the array horizontally and using couplers to share at least some radiating elements from two side-by-side arrays to increase the array's aperture in the azimuth plane. While both techniques are effective in reducing AZBW, staggered array designs may reduce three-dimensional (3D) directivity and gain, and coupler schemes may increase insertion loss and reduce gain. Moreover, coupler schemes are not suitable for antennas with a single row of low-frequency band radiating elements.

[0054] This disclosure provides a base station antenna including a phase-gradient meta-surface (PGM), which can be used to accelerate phase changes in the radiation pattern to narrow the AZBW. A PGM is an artificial material with a special structure and function that can manipulate the phase, amplitude, and polarization characteristics of electromagnetic waves. A PGM is typically composed of multiple tiny units (called "metasurface units" or "PGM units"). By designing the arrangement and shape of these units, phase modulation of the incident electromagnetic waves can be achieved. A PGM can also efficiently reflect or transmit electromagnetic waves of specific frequencies while remaining transparent to electromagnetic waves of other frequencies. By incorporating a PGM into the base station antenna of this disclosure, a phase gradient can be applied to the antenna beam, accelerating the phase change of the antenna beam to reduce the AZBW of the generated antenna beam.

[0055] The base station antennas according to various embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It will be understood that actual base station antennas may include other components, but to avoid obscuring the essential points of this disclosure, these other components will not be discussed herein and are not shown in the drawings. For ease of explanation, in the various drawings, the Z-direction is the direction for mounting the antenna (typically a direction perpendicular to the ground plane), the Y-direction is the direction transverse to the antenna backplane, which, together with the Z-direction, defines the plane containing the antenna backplane, and the X-direction is the direction perpendicular to the antenna backplane. It will be understood that since antennas are typically mounted vertically, the description herein of one element being in front of another element is done with the antenna viewed directly.

[0056] It will be understood that in the accompanying drawings, the base station antenna is shown with a radiating element extending upwards from the antenna's reflector. In use, the base station antenna is rotated 90° so that the radiating element is positioned in front of the reflector. The following description will describe the relative positioning of the base station antenna components as if the base station antenna were installed for use, even though the base station antenna has been rotated 90° relative to the orientation shown in the accompanying drawings.

[0057] Figure 1 This is a schematic side view of a small portion of a base station antenna 100 according to some embodiments of the present disclosure, wherein the antenna radome and various other components are omitted. Figure 1 As shown, the base station antenna 100 includes a reflector 110 and a radiating element 120. The radiating element 120 typically includes a feed rod 124 and a radiator 122 located at the front end of the feed rod 124. The feed rod 124 is mounted to extend forward from the reflector 110 such that the radiator 122 is positioned in front of the reflector 110. The radiator 122 is configured to operate within a first operating frequency range (e.g., a low-frequency band). The reflector 110 can be used to reflect the back radiation of the radiator 122 back forward.

[0058] The base station antenna 100 also includes a dielectric substrate 134 located between the radiator 122 and the reflector 110. The dielectric substrate 134 has a conductive element array 132 disposed thereon. The dielectric substrate 134 with the conductive element array 132 can constitute a PGM 130. The PGM 130 is capable of applying a phase gradient to the radiation incident on the PGM 130. For example, such radiation may include radiation directly from the radiator 122, or radiation reflected onto the PGM by the reflector 110. Figure 11 The amplitude and phase of radiation reflected by the PGM and radiation transmitted by the PGM are illustrated exemplarily as a function of frequency. From Figure 11 As can be seen, the PGM 130 is able to apply a phase gradient to the antenna beam in the frequency space.

[0059] The PGM 130, in conjunction with the reflector 110, provides substantially complete reflection of the rearward radiation emitted by the radiator 122. "Substantially complete reflection" as used herein can mean that more than 95% of the rearward radiation is reflected, for example, at least 97% of the rearward radiation is reflected, more preferably, at least 99% of the rearward radiation is reflected, and most preferably, 100% of the rearward radiation is reflected. For example, the PGM can reflect a first portion of the rearward radiation from the radiator 122, and the reflector 110 can reflect a second portion of the rearward radiation from the radiator 122, which is transmitted through the PGM 130.

[0060] When radiator 122 is in operation, PGM 130 can, on the one hand, perform phase control on radiation within a first operating frequency range incident on it, and on the other hand, together with reflector 110, enhance the reflection of back radiation from radiator 122, thereby reducing the AZBW of the antenna beam emitted by radiator 122.

[0061] In some embodiments, the radiator 122 is positioned approximately one-quarter of the wavelength at the center operating frequency of a first operating frequency range in front of the reflector 110, and the conductive element array 132 is positioned approximately one-eighth of the wavelength at the center operating frequency of the first operating frequency range in front of the reflector 110. In some embodiments, the electrical length of the radiator 122 is approximately one-quarter of the wavelength at the center operating frequency of the first operating frequency range. In this document, "approximately" may mean equal to the described value or within ±20% of the described value, preferably within ±10%, more preferably within ±5%, and most preferably within ±1%.

[0062] The conductive cell array 132 and the dielectric substrate 134 can be fabricated using any suitable material. For example, they can be fabricated using a printed circuit board (PCB) process. Examples of materials used to form the conductive cell array include, but are not limited to, high-conductivity materials such as copper, gold, and silver, or combinations thereof.

[0063] Additionally, the conductive cells in the conductive cell array 132 can be designed according to the desired characteristics of the PGM 130. Having rotational symmetry in the conductive cells may be advantageous for the radiation pattern. For example, each conductive cell in the conductive cell array 132 may include a conductive trace having a substantially circular outer contour. Such a conductive trace can be closed, thus allowing it to operate as an inductor. Each conductive cell may also include a substantially square conductive patch disposed within a perimeter defined by the conductive trace segment. Such a conductive patch can be spaced apart from the conductive trace, and the gap between them can form a capacitor. By designing the specific shape, size, spacing, etc., of the conductive trace and / or the conductive patch, an equivalent LC resonant circuit with desired equivalent inductance and equivalent capacitance values ​​can be achieved. In some embodiments, the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of a first operating frequency range. In some embodiments, the side length of the conductive patch is approximately the same as the outer radius of the conductive trace, i.e., the sum of the inner radius and the width of the conductive trace.

[0064] Figure 2 Two non-limiting examples of conductive units are shown, wherein (A) depicts a conductive unit with a ring-shaped conductive trace, and (B) depicts a conductive unit with a ring-shaped conductive trace and a square conductive patch located at the center of the ring-shaped conductive trace. For example, when the first operating frequency range is a low frequency band, for a center operating frequency of 827 MHz, the ring-shaped conductive trace may have an inner radius of 32 mm and a width of 2 mm, and the square conductive patch may have a side length of 34 mm.

[0065] Figure 3A base station antenna 100' according to some other embodiments of the present disclosure is shown. Compared to base station antenna 100, base station antenna 100' further includes a pair of radiating elements 140. Each radiating element 140 includes a feed rod 144 and a radiator 142 located at the front end of the feed rod 144. The feed rod 144 is mounted to extend forward from reflector 110 such that the radiator 142 is located in front of reflector 110. The radiator 142 is configured to operate in a second operating frequency range (e.g., intermediate frequency band) above a first operating frequency range. Reflector 110 can be used to reflect back-radiated radiation emitted by radiator 142 back in a forward direction. In an example embodiment, radiating element 120 may be a low-frequency band radiating element, and radiating element 140 may be an intermediate frequency band radiating element.

[0066] like Figure 3 As shown, radiator 142 is closer to reflector 110 than conductive element array 132. In some cases, radiator 142 may be located between conductive element array 132 and reflector 110. That is, in a front view of base station antenna 100', radiator 142 may be behind PGM 130. Therefore, it is desirable for PGM 130 to be "stealthy" of the radiation emitted by radiator 142, so that the radiation emitted by radiator 142 is not blocked by PGM 130. For example, PGM 130 may be configured to allow radiation in a second operating frequency range to pass through it. In some embodiments, a choke may be formed in the conductive trace of each conductive element in conductive element array 132. The current induced in the conductive trace by radiation in the second operating frequency range will be reversed on the opposite side of the choke, thereby canceling out radiation in the far field. Specifically, the choke may include a first portion and a second portion, wherein current induced in the first portion by radiation within a second operating frequency range flows in a first direction, and current induced in the second portion by radiation within the second operating frequency range flows in a second direction opposite to the first direction. In some examples, the length of the choke may be approximately one-quarter of the wavelength at the center operating frequency of the second operating frequency range.

[0067] Figure 4 A non-limiting example of a conductive unit in which four chokes are formed is shown. For example... Figure 4As shown, multiple arc-shaped conductive segments and multiple U-shaped conductive segments are alternately connected to form a closed conductive trace with a substantially circular outer contour. These U-shaped conductive segments act as chokes, and their length can be approximately one-quarter of the wavelength at the center operating frequency of the second operating frequency range. The lengths of the individual arc-shaped conductive segments can be the same, and the inner radius of the conductive trace can be approximately one-tenth of the wavelength at the center operating frequency of the first operating frequency range. For example, when the first operating frequency range is a low-frequency band and the second operating frequency band is a mid-frequency band, the inner radius of the conductive trace can be 32 mm, the lengths of the two long sides of the U-shaped conductive segments can each be 15.7 mm, and the length of the short side of the U-shaped conductive segments can be 7 mm, making the total length of the U-shaped conductive segments 38.4 mm. Taking the bottommost U-shaped conductive segment as an example, radiation within the second operating frequency range induces upward-flowing currents and downward-flowing currents in the left and right portions of this U-shaped conductive segment, respectively, thereby canceling out radiation in the far field.

[0068] With the help of the choke, the PGM 130 has little or no impact on the operation of the radiator 142. Therefore, the arrangement of the radiating element 140 and the PGM 130 can be considered separately without worrying that overlapping layouts will affect the operating performance of the radiating element 140. This is beneficial for promoting high integration and miniaturization of the base station antenna while maintaining high performance. In some embodiments, the radiator 122 is about one-quarter of the wavelength at the center operating frequency of the first operating frequency range from the reflector 110, the conductive element array 132 is about one-eighth of the wavelength at the center operating frequency of the first operating frequency range from the reflector 110, and the radiator 142 is about one-quarter of the wavelength at the center operating frequency of the second operating frequency range from the reflector 110.

[0069] It should be understood that a corresponding PGM can also be set between the radiator 142 and the reflector 110 to optimize the AZBW of the radiator 142. Considering that the radiator 142 typically operates in the mid-frequency band and therefore already has a good AZBW, it is possible to determine whether to set a PGM for it based on actual needs.

[0070] The accompanying figures are primarily for illustrative purposes. Figure 2 The conductive unit is illustrated by example (A), but this is merely exemplary and not limiting.

[0071] In some embodiments, the radiating element 120 may be a dipole radiating element, and the radiator 122 may be a dipole radiator. The radiating element may be a single-polarized radiating element, in which case it will have a single dipole radiator 122, or the radiating element may be a dual-polarized radiating element, in which case it will have two dipole radiators 122. It should be understood that in other embodiments, the base station antenna may use different types of radiating elements. Therefore, for example, in other embodiments, the radiating element 120 may be implemented as a patch radiating element, a slot radiating element, a horn radiating element, or any other suitable radiating element, and these radiating elements may be single-polarized or dual-polarized radiating elements.

[0072] For a single-polarized dipole radiator, the conductive elements in the conductive element array 132 can be arranged along its single dipole. For a dual-polarized dipole radiator, the conductive elements in the conductive element array 132 can be arranged along one or both dipoles. In the following figures, for illustrative purposes, the radiator 122 is depicted primarily as an example of a dual-polarized dipole radiator, but this is merely exemplary and not limiting.

[0073] In some embodiments, the radiator 122 includes a first dipole arranged along a first axis. The conductive element array 132 may include a first plurality of conductive elements arranged along the first axis. For example, Figure 5 An example embodiment 100A of a base station antenna 100 is shown, wherein a radiator 122 includes a first dipole 1222 (also described herein as tilted at -45°) arranged along a first axis (e.g., the bisection of the first and third quadrants in a YZ coordinate system), and a conductive element array 132 includes a first plurality of conductive elements 1322 arranged along the first axis. In some examples, such as Figure 5 As shown, the projection area of ​​the first dipole 1222 on the reflector 110 falls within the projection area of ​​the first plurality of conductive units 1322 on the reflector 110, which is beneficial for narrowing the AZBW of its radiation beam when the first dipole 1222 is activated.

[0074] In some embodiments, the first plurality of conductive units are of the same size as each other, for example, Figure 5 As shown. In other embodiments, the size of the first plurality of conductive units gradually increases in a direction parallel to the first axis. For example, Figure 6An example embodiment 100B of the base station antenna 100 is shown, in which each conductive element sequentially increases in size in a direction of 45° clockwise rotation relative to the Z direction. The smaller the size of the conductive element, the earlier the phase of the beam. Therefore, by gradually changing the size of the conductive elements in the conductive element array 132, the PGM 130 can apply a phase gradient to the antenna beam in the location space. The phase difference of the beam incident on the PGM 130 at the corresponding positions can be achieved by utilizing the size difference of the conductive elements located at both ends of the PGM 130. In other embodiments, the individual conductive elements may also be changed to sequentially increase in size in a direction of 135° counterclockwise rotation relative to the Z direction. By controlling the direction of increase in the size of the conductive elements, the maximum beam orientation of the antenna can be modulated. In other words, the direction of increase in the size of the conductive elements can be determined based on the desired maximum beam orientation of the antenna.

[0075] The first plurality of conductive units 1322 may include any number of conductive units. In some embodiments, the first plurality of conductive units 1322 includes at least one conductive unit located behind the first dipole arm of the first dipole 1222 and at least one conductive unit located behind the second dipole arm of the first dipole 1222. The number of conductive units located behind the first dipole arm of the first dipole 1222 and the number of conductive units located behind the second dipole arm of the first dipole 1222 may be the same or different, depending on the specific installation conditions (e.g., installation interference with other nearby components).

[0076] In some embodiments, the radiator 122 includes a second dipole arranged along a second axis substantially perpendicular to the first axis. "Substantially perpendicular" as used herein means an angle between the two axes between 70° and 110°, preferably between 80° and 100°, more preferably between 85° and 95°, and most preferably 90°. The conductive element array 132 may include a second plurality of conductive elements arranged along the second axis. For example, Figure 7 An example embodiment 100C of a base station antenna 100 is shown, wherein a radiator 122 includes a first dipole 1222 arranged along a first axis (e.g., the bisection of the first and third quadrants in a YZ coordinate system) and a second dipole 1224 arranged along a second axis (e.g., the bisection of the second and fourth quadrants in a YZ coordinate system), and a conductive element array 132 includes a first plurality of conductive elements 1322 arranged along the first axis and a second plurality of conductive elements 1324 arranged along the second axis. In some examples, such as Figure 7As shown, the projection area of ​​the second dipole 1224 on the reflector 110 falls within the projection area of ​​the second plurality of conductive units 1324 on the reflector 110, which is beneficial for narrowing the AZBW of its radiation beam when the second dipole 1224 is activated.

[0077] In some embodiments, the second plurality of conductive units are of the same size as each other, for example, Figure 7 As shown. In other embodiments, the size of the second plurality of conductive elements gradually increases in a direction parallel to the second axis. As previously described, the maximum beam orientation of the antenna can be modulated by controlling the direction of the increase in the size of the conductive elements.

[0078] The second plurality of conductive units 1324 may include any number of conductive units, and may include the same or different number of conductive units as the first plurality of conductive units 1322. In some embodiments, the second plurality of conductive units 1324 includes at least one conductive unit located behind the third dipole arm of the second dipole 1224 and at least one conductive unit located behind the fourth dipole arm of the second dipole 1224. The number of conductive units located behind the third dipole arm of the second dipole 1224 and the number of conductive units located behind the fourth dipole arm of the second dipole 1224 may be the same or different, depending on the specific installation conditions (e.g., installation interference with other nearby components).

[0079] In some other embodiments, the conductive unit array 132 may also not include conductive units arranged along the second axis, for example, Figure 5 and Figure 6 As shown.

[0080] The conductive units in the conductive unit array 132 can be arranged on the same dielectric substrate 134 or distributed on multiple dielectric substrates 134, depending on the mounting situation (e.g., mounting interference with other nearby components).

[0081] In some embodiments, such as Figure 5 As shown, the conductive element array 132 includes a first subarray 1322A located on a first side of the feed rod 124 (obscured in the figure) and a second subarray 1322B located on a second side of the feed rod 124 opposite to the first side. For ease of installation, the first subarray 1322A and the second subarray 1322B can be placed as close to each other as possible, thereby facilitating miniaturization of the base station antenna and avoiding interference with other components.

[0082] In some embodiments, such as Figure 5 and Figure 7As shown, the dielectric substrate 134 includes an opening 136 located between the first subarray 1322A and the second subarray 1322B, through which the feed rod 124 can extend.

[0083] In some embodiments, such as Figure 6 As shown, the dielectric substrate 134 includes a first dielectric substrate 1342 and a second dielectric substrate 1344. A first subarray 1322A is disposed on the first dielectric substrate 1342, and a second subarray 1322B is disposed on the second dielectric substrate 1344. A feed rod 124 extends through the gap 138 between the first dielectric substrate 1342 and the second dielectric substrate 1344.

[0084] In some embodiments, the conductive unit array 132 may include conductive units located at the feed rod 124. For example... Figure 8 An example embodiment 100D of a base station antenna 100 is shown, wherein the conductive element array 132 includes conductive elements 1322C located at a feed rod 124, and the dielectric substrate 134 includes an opening 136 located in the conductive elements 1322C, through which the feed rod 124 extends.

[0085] In some embodiments, the base station antenna 100 includes a plurality of radiators 122 arranged in a single row. Each radiator 122 includes a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis. A corresponding conductive element array 132 is disposed between each radiator 122 and a reflector 110. The conductive element array 132 includes a first plurality of conductive elements arranged along the first axis and a second plurality of conductive elements arranged along the second axis. For example, Figure 9 An example embodiment 100E of a base station antenna 100 is shown, in which a plurality of radiating elements 120 are arranged in a single column, with a corresponding PGM 130 (more specifically, an array of conductive elements) disposed between the radiator and reflector 110 of each radiating element 120. For this single-column configuration, it may be more advantageous to provide a plurality of conductive elements arranged along each of the two dipoles of the radiator of each radiating element 120.

[0086] In some embodiments, the base station antenna 100 includes a plurality of radiators 122 arranged in two columns. Each radiator 122 includes a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis. A corresponding conductive element array 132 is disposed between each radiator 122 and a reflector 110. The conductive element array 132 includes a first plurality of conductive elements arranged along the first axis but excludes conductive elements arranged along the second axis. For example, Figure 10An example embodiment 100F of a base station antenna 100 is shown, in which a plurality of radiating elements 120 are arranged in a double column, with a corresponding PGM 130 (more specifically, an array of conductive elements) disposed between the radiator and reflector 110 of each radiating element 120. For this double-column configuration, it may be more advantageous to provide a plurality of conductive elements along one of the two dipoles of the radiator of each radiating element 120 instead of providing a plurality of conductive elements along the other dipole. The PGM 130 can be set for each dipole of each radiating element 120 individually, depending on the specific circumstances (e.g., installation interference, antenna maximum beam orientation, etc.).

[0087] Figure 12 A schematic front view of a base station antenna 200A according to a first comparative example and a base station antenna 200B according to a second exemplary embodiment of the present disclosure are depicted. Base station antennas 200A and 200B each include a dual-row low-frequency radiating element 220 mounted on a reflector 210. Compared to base station antenna 200A, base station antenna 200B further includes a PGM 230 configured for a dipole of the low-frequency radiating element 220. Figure 13 The radiation patterns of base station antennas 200A and 200B are shown. From Figure 14 As can be seen, the addition of PGM 230 enhances peak directivity and peak realized gain. Table 1 below shows a comparison of some performance parameters of base station antennas 200A and 200B. It can be seen that the addition of PGM 230 not only reduces AZBW but also enhances AZ directivity (i.e., the directivity of the beam in the azimuth plane).

[0088] Table 1

[0089]

[0090]

[0091] Figure 15A schematic front view of a base station antenna 300A according to a second comparative example and base station antennas 300B, 300C, and 300D according to third to fifth exemplary embodiments of this disclosure is depicted. Each of the base station antennas 300A, 300B, 300C, and 300D includes a single-row low-frequency band radiating element 320 mounted on a reflector 310. Compared to the base station antenna 300A, the base station antennas 300B, 300C, and 300D further include PGMs 330B, 330C, and 330D arranged for two dipoles of the low-frequency band radiating element 320. The number of conductive elements included in the PGMs 330B, 330C, and 330D decreases sequentially. Table 2 below shows a comparison of some performance parameters of the base station antennas 300A, 300B, 300C, and 300D. It can be seen that the addition of the PGM 330 not only reduces the AZBW and ELBW (elevation beamwidth) but also enhances peak directivity and achieves gain. Furthermore, even with a reduction in the number of conductive units, AZBWs can still be narrowed.

[0092] Table 2

[0093] Electrical Specifications 300A 300B 300C 300D 3dB AZBW(°) 72 67.3 66.7 70 10dB AZBW(°) 129.8 128.2 125.2 128.5 3dB ELBW (°) 75.8 62.6 71.1 73.9 10dB ELBW (°) 131.9 125.3 128.6 130.6 Peak directivity (dB) 8.58 9.0 8.9 8.69 Achieve gain (dB) 8.18 8.8 8.64 8.39 Radiation efficiency (%) 98 98 98 98 Overall efficiency (%) 91 95 94 93

[0094] Figure 16 A perspective view and a front view of a base station antenna according to a third comparative example 400A and base station antennas 400B and 400C according to the sixth to seventh exemplary embodiments of this disclosure are schematically depicted. Each of the base station antennas 400A, 400B, and 400C includes a single-row low-frequency radiating element 420 and a dual-row mid-frequency radiating elements 432, 434, 436, and 438 mounted on a reflector 410. Compared to base station antenna 400A, base station antennas 400B and 400C further include PGMs 440B and 440C configured for two dipoles of the low-frequency radiating element 420. The conductive element of the PGM 440B employs... Figure 2 In design (A), the conductive unit of PGM440C adopts Figure 4 The design.

[0095] Figure 17 The radiation patterns of base station antennas 400A, 400B, and 400C are shown when the dipoles of two adjacent intermediate frequency band radiating elements 432 and 434, tilted at +45°, are activated. Figure 18 The 3D directivity and realized gain are shown. It can be seen that, compared to the PGM440B, the PGM 440C achieves better 3D directivity and realized gain due to the "stealth" of the mid-band radiating element. Table 3 below shows a comparison of some performance parameters of the base station antennas 400A and 400C. It can be seen that the addition of the PGM 440C also narrows the AZBW of the mid-band radiation.

[0096] Table 3

[0097]

[0098] Figure 19 The radiation patterns of base station antennas 400A and 400C are shown when the dipole tilted at +45° in the low-frequency radiating element 420 is activated. (Combined with...) Figure 20 It can be seen that the addition of PGM 440C enhances the 3D directivity of low-frequency radiation and achieves gain, while reducing AZBW by 3dB and AZBW by 10dB.

[0099] Figure 21 The radiation patterns of base station antennas 400A and 400C are shown when the dipole tilted at -45° in the low-frequency radiating element 420 is activated. (Combined with...) Figure 22 It can be seen that the addition of PGM 440C enhances the 3D directivity of low-frequency radiation and achieves gain, and reduces the AZBW by 3dB.

[0100] The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “upper,” “lower,” “high,” “lower,” etc., used in the specification and claims, if present, are for descriptive purposes and not necessarily for describing unchanging relative positions. It should be understood that such terms are interchangeable where appropriate, so that embodiments of this disclosure described herein can operate, for example, in orientations different from those shown or otherwise described herein. For example, when the device in the drawings is reversed, a feature previously described as “above” other features may now be described as “below” other features. The device may also be oriented in other ways (rotated 90 degrees or in other orientations), in which case the relative spatial relationships will be interpreted accordingly.

[0101] In the specification and claims, when an element is described as being "on top of," "attached to," "connected to," "coupled to," or "in contact with" another element, the element may be directly located on top of, directly attached to, directly connected to, directly coupled to, or directly in contact with the other element, or one or more intermediate elements may be present. Conversely, when an element is described as being "directly" located on top of, directly attached to, directly connected to, directly coupled to, or directly in contact with another element, no intermediate elements are present. In the specification and claims, when a feature is arranged "adjacent" to another feature, it may mean that a feature has a portion overlapping with the adjacent feature or a portion located above or below the adjacent feature.

[0102] As used herein, the term "exemplary" means "serving as an example, instance, or illustration," and not as a "model" to be precisely copied. Any implementation described herein by example is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, this disclosure is not limited to any theory expressed or implied as given in the art, background, summary of the invention, or detailed description.

[0103] As used herein, the term "substantially" means any minor variation resulting from design or manufacturing defects, device or component tolerances, environmental influences, and / or other factors. The term "substantially" also allows for differences from the perfect or ideal situation due to parasitic effects, noise, and other practical considerations that may exist in the actual implementation.

[0104] Additionally, terms such as “first,” “second,” etc., may be used in this document for reference purposes only and are not intended to be limiting. For example, unless the context clearly indicates otherwise, the words “first,” “second,” and other such numerical terms relating to structures or elements do not imply order or sequence.

[0105] It should also be understood that the term "including / comprises" as used herein indicates the presence of the indicated feature, whole, step, operation, unit, and / or component, but does not preclude the presence or addition of one or more other features, wholes, steps, operations, units, and / or components, and / or combinations thereof. In this disclosure, the term "provide" is used broadly to cover all ways of obtaining an object; therefore, "providing an object" includes, but is not limited to, "purchasing," "preparing / manufacturing," "arranging / setting," "installing / assembling," and / or "ordering" an object.

[0106] As used herein, the term “and / or” includes any and all combinations of one or more of the listed items in association. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise.

[0107] The same or similar parts between the various embodiments of this disclosure can be referred to mutually, and each embodiment focuses on describing the differences from other embodiments. In the description of this disclosure, the reference to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," "exemplary," etc., means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this disclosure, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this disclosure and the features of the different embodiments or examples.

[0108] Additionally, when used in this disclosure, the terms “here,” “above,” “below,” “this,” “the following,” “the text,” “the preceding,” and similar terms should refer to the entire disclosure and not any particular part of it. Furthermore, unless expressly stated otherwise or otherwise understood in the context in which they are used, conditional language used herein, such as “may,” “possibly,” “for example,” “like,” etc., is generally intended to express that certain embodiments include, while other embodiments do not, certain features, elements, and / or states. Therefore, such conditional language is not generally intended to imply that one or more embodiments require features, elements, and / or states in any way, or whether such features, elements, and / or states are included or performed in any particular embodiment.

[0109] Those skilled in the art will recognize that the boundaries between the above operations are merely illustrative. Multiple operations may be combined into a single operation, a single operation may be distributed among additional operations, and operations may be performed with at least partial overlap in time. Moreover, alternative embodiments may include multiple instances of a particular operation, and the order of operations may be changed in various other embodiments. However, other modifications, variations, and substitutions are equally possible. Aspects and elements of all the embodiments disclosed above may be combined in any way and / or in combination with aspects or elements of other embodiments to provide multiple additional embodiments. Therefore, this specification and the accompanying drawings should be considered illustrative rather than restrictive.

[0110] In addition, this disclosure may also include the following embodiments.

[0111] 1. A base station antenna, comprising:

[0112] Reflector;

[0113] A first radiator, located in front of the reflector and configured to operate within a first operating frequency range; and

[0114] A dielectric substrate is located between the first radiator and the reflector, and an array of conductive units is disposed thereon.

[0115] The dielectric substrate having the conductive unit array forms a phase gradient metasurface (PGM), which is configured to apply a phase gradient to radiation within the first operating frequency range incident on the PGM.

[0116] 2. The base station antenna according to claim 1, wherein the PGM and the reflector are configured to cooperate together to reflect at least 97% of the radiation emitted rearward by the first radiator.

[0117] 3. The base station antenna according to claim 1, wherein the PGM is configured to reflect a first portion of the rearward radiation emitted by the first radiator, and the reflector is configured to reflect a second portion of the rearward radiation emitted by the first radiator, the second portion being transmitted through the PGM.

[0118] 4. The base station antenna according to claim 1, comprising:

[0119] A second radiator, located in front of and closer to the reflector than the conductive element array, is configured to operate within a second operating frequency range, which is higher than the first operating frequency range.

[0120] The PGM is configured to allow radiation within the second operating frequency range to pass through it.

[0121] 5. The base station antenna according to claim 1, wherein each conductive element in the conductive element array includes a conductive trace having a substantially circular outer contour.

[0122] 6. The base station antenna according to claim 5, wherein the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of the first operating frequency range.

[0123] 7. The base station antenna according to claim 5, wherein each conductive element includes a substantially square conductive patch disposed within a perimeter defined by the conductive trace segment.

[0124] 8. The base station antenna according to claim 7, wherein the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of the first operating frequency range, and the side length of the conductive patch is approximately the same as the outer radius of the conductive trace.

[0125] 9. The base station antenna according to claim 5, wherein a choke is provided in the conductive trace.

[0126] 10. The base station antenna according to claim 9, comprising:

[0127] A second radiator, located between the conductive element array and the reflector, is configured to operate within a second operating frequency range, which is higher than the first operating frequency range.

[0128] The length of the choke is approximately one-quarter of the wavelength at the center operating frequency of the second operating frequency range.

[0129] 11. The base station antenna according to claim 1, wherein the first radiator includes a first dipole arranged along a first axis.

[0130] The conductive unit array includes a first plurality of conductive units arranged along the first axis.

[0131] 12. The base station antenna according to 11, wherein the size of the first plurality of conductive elements gradually increases in a direction parallel to the first axis.

[0132] 13. The base station antenna according to 11, wherein the first plurality of conductive elements are of the same size as each other.

[0133] 14. The base station antenna of claim 11, wherein the first radiator includes a second dipole arranged along a second axis substantially perpendicular to the first axis.

[0134] The conductive unit array includes a second plurality of conductive units arranged along the second axis.

[0135] 15. The base station antenna of claim 11, wherein the first radiator includes a second dipole arranged along a second axis substantially perpendicular to the first axis.

[0136] The conductive unit array does not include conductive units arranged along the second axis.

[0137] 16. The base station antenna according to claim 1, wherein the base station antenna includes a plurality of first radiators arranged in a single row, each of the plurality of first radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, and a corresponding conductive element array is disposed between each of the plurality of first radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis and a second plurality of conductive elements arranged along the second axis.

[0138] 17. The base station antenna according to claim 1, wherein the base station antenna includes a plurality of first radiators arranged in two columns, each of the plurality of first radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, and a corresponding conductive element array is disposed between each of the plurality of first radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis but excluding conductive elements arranged along the second axis.

[0139] 18. The base station antenna according to claim 1, wherein the first radiator is located at the front end of a first feed rod extending forward from the reflector, and the conductive element array includes a first subarray located on a first side of the first feed rod and a second subarray located on a second side of the first feed rod opposite to the first side.

[0140] 19. The base station antenna according to 18, wherein the dielectric substrate includes a first dielectric substrate and a second dielectric substrate, the first subarray is disposed on the first dielectric substrate, the second subarray is disposed on the second dielectric substrate, and the first feed rod extends through the gap between the first dielectric substrate and the second dielectric substrate.

[0141] 20. The base station antenna of claim 18, wherein the dielectric substrate includes an opening between the first subarray and the second subarray, and the first feed rod extends through the opening.

[0142] 21. The base station antenna according to claim 18, wherein the conductive element array includes conductive elements located at the first feed rod, the dielectric substrate includes an opening in the conductive element, and the first feed rod extends through the opening.

[0143] 22. The base station antenna according to claim 1, wherein the first radiator and the reflector are located at approximately one-quarter of the wavelength at the center operating frequency of the first operating frequency range, and the conductive element array and the reflector are located at approximately one-eighth of the wavelength at the center operating frequency of the first operating frequency range.

[0144] 23. A base station antenna, comprising:

[0145] Reflector;

[0146] Radiator, the radiator being located in front of the reflector; and

[0147] A dielectric substrate is located between the radiator and the reflector, and an array of conductive units is disposed thereon.

[0148] Each conductive unit in the conductive unit array includes a conductive trace having a substantially circular outer contour.

[0149] 24. The base station antenna according to 23, wherein the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of the radiator's operating frequency range.

[0150] 25. The base station antenna according to claim 23, wherein each conductive element includes a substantially square conductive patch disposed within a perimeter defined by the conductive trace segment.

[0151] 26. The base station antenna according to 25, wherein the inner radius of the conductive trace is approximately one-tenth of the wavelength at the center operating frequency of the radiator's operating frequency range, and the side length of the conductive patch is approximately the same as the outer radius of the conductive trace.

[0152] 27. The base station antenna according to 23, wherein a choke is provided in the conductive trace.

[0153] 28. The base station antenna according to 27, wherein the length of the choke is approximately one-quarter of the wavelength at the center operating frequency of another operating frequency range higher than the operating frequency range of the radiator.

[0154] 29. The base station antenna according to claim 23, wherein the radiator includes a first dipole arranged along a first axis.

[0155] The conductive unit array includes a first plurality of conductive units arranged along the first axis.

[0156] 30. The base station antenna according to 29, wherein the size of the first plurality of conductive elements gradually increases in a direction parallel to the first axis.

[0157] 31. The base station antenna according to claim 29, wherein the first plurality of conductive elements are of the same size as each other.

[0158] 32. The base station antenna according to claim 29, wherein the radiator includes a second dipole arranged along a second axis substantially perpendicular to the first axis.

[0159] The conductive unit array includes a second plurality of conductive units arranged along the second axis.

[0160] 33. The base station antenna according to claim 29, wherein the radiator includes a second dipole arranged along a second axis substantially perpendicular to the first axis.

[0161] The conductive unit array does not include conductive units arranged along the second axis.

[0162] 34. The base station antenna according to claim 23, wherein the base station antenna includes a plurality of radiators arranged in a single row, each of the plurality of radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, and a corresponding conductive element array is disposed between each of the plurality of radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis and a second plurality of conductive elements arranged along the second axis.

[0163] 35. The base station antenna of claim 23, wherein the base station antenna includes a plurality of radiators arranged in two columns, each of the plurality of radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, and a corresponding conductive element array is disposed between each of the plurality of radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis but excluding conductive elements arranged along the second axis.

[0164] 36. The base station antenna according to claim 23, wherein the radiator is located at the front end of a feed rod extending forward from the reflector, and the conductive element array includes a first subarray located on a first side of the feed rod and a second subarray located on a second side of the feed rod opposite to the first side.

[0165] 37. The base station antenna according to 36, wherein the dielectric substrate includes a first dielectric substrate and a second dielectric substrate, the first subarray is disposed on the first dielectric substrate, the second subarray is disposed on the second dielectric substrate, and the feed rod extends through the gap between the first dielectric substrate and the second dielectric substrate.

[0166] 38. The base station antenna of claim 36, wherein the dielectric substrate includes an opening between the first subarray and the second subarray, and the feed rod extends through the opening.

[0167] 39. The base station antenna according to 36, wherein the conductive element array includes conductive elements located at the feed rod, the dielectric substrate includes an opening in the conductive element, and the feed rod extends through the opening.

[0168] 40. The base station antenna according to claim 23, wherein the radiator and the reflector are located at approximately one-quarter of the wavelength at the center operating frequency of the radiator's operating frequency range, and the conductive element array and the reflector are located at approximately one-eighth of the wavelength at the center operating frequency of the radiator's operating frequency range.

[0169] While specific embodiments of this disclosure have been described in detail by way of example, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. The various embodiments disclosed herein can be combined in any way without departing from the spirit and scope of this disclosure. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A base station antenna comprising: a reflector; a first radiator located in front of the reflector and configured to operate in a first operating frequency range; and a dielectric substrate located between the first radiator and the reflector and having disposed thereon an array of electrically conductive elements, wherein the dielectric substrate with the array of electrically conductive elements constitutes a phase-gradient metasurface (PGM) configured to impart a phase gradient to radiation in the first operating frequency range incident on the PGM.

2. The base station antenna of claim 1, wherein: the PGM and the reflector are configured to cooperate together to reflect at least 97% of radiation emitted backwards by the first radiator; and / or the PGM is configured to reflect a first portion of radiation emitted backwards by the first radiator, the reflector is configured to reflect a second portion of radiation emitted backwards by the first radiator, the second portion being transmitted through the PGM.

3. The base station antenna of claim 1, comprising: a second radiator located in front of the reflector and closer to the reflector than the array of electrically conductive elements, the second radiator being configured to operate in a second operating frequency range, the second operating frequency range being higher than the first operating frequency range, wherein the PGM is configured to allow radiation in the second operating frequency range to pass through the PGM. each electrically conductive element of the array of electrically conductive elements comprises an electrically conductive trace having a substantially circular outer profile; 4. The base station antenna of Claim 1, wherein, optionally, an inner radius of the electrically conductive trace is approximately one tenth of a wavelength at a centre operating frequency of the first operating frequency range; or optionally, each electrically conductive element comprises a substantially square electrically conductive patch disposed within a perimeter defined by the electrically conductive trace segment; or optionally, an inner radius of the electrically conductive trace is approximately one tenth of a wavelength at a centre operating frequency of the first operating frequency range, a side length of the electrically conductive patch is approximately the same length as an outer radius of the electrically conductive trace; or optionally, a choke is disposed in the electrically conductive trace. the first radiator comprises a first dipole arranged along a first axis, 5. The base station antenna of Claim 1, wherein, wherein the array of electrically conductive elements comprises a first plurality of electrically conductive elements arranged along the first axis; or optionally, a size of the first plurality of electrically conductive elements gradually increases in a direction parallel to the first axis, alternatively, the size of the first plurality of electrically conductive elements is the same as each other; or optionally, the first radiator comprises a second dipole arranged along a second axis substantially perpendicular to the first axis; or optionally, the array of electrically conductive elements comprises a second plurality of electrically conductive elements arranged along the second axis, alternatively, the array of electrically conductive elements does not comprise electrically conductive elements arranged along the second axis. ​ 6. The base station antenna of Claim 1, wherein, The base station antenna includes a plurality of first radiators arranged in a single column, each of the plurality of first radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, a respective one of the conductive element arrays being disposed between each of the plurality of first radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis and a second plurality of conductive elements arranged along the second axis.

7. The base station antenna of Claim 1, wherein, The base station antenna includes a plurality of first radiators arranged in a single column, each of the plurality of first radiators including a first dipole arranged along a first axis and a second dipole arranged along a second axis substantially perpendicular to the first axis, a respective one of the conductive element arrays being disposed between each of the plurality of first radiators and the reflector, the conductive element array including a first plurality of conductive elements arranged along the first axis and a second plurality of conductive elements arranged along the second axis.

8. The base station antenna of Claim 1, wherein, The first radiators are located at a front end of a first feed pole extending forwardly from the reflector, the conductive element array including a first sub-array located at a first side of the first feed pole and a second sub-array located at a second side of the first feed pole opposite the first side; Optionally, the dielectric substrate includes a first dielectric substrate and a second dielectric substrate, the first sub-array being disposed on the first dielectric substrate and the second sub-array being disposed on the second dielectric substrate, the first feed pole extending through a gap between the first dielectric substrate and the second dielectric substrate; or Optionally, the dielectric substrate includes an opening between the first sub-array and the second sub-array, the first feed pole extending through the opening; or Optionally, the conductive element array includes a conductive element at the first feed pole, the dielectric substrate including an opening in the conductive element, the first feed pole extending through the opening.

9. The base station antenna of Claim 1, wherein, The first radiators are located at a front end of a first feed pole extending forwardly from the reflector, the conductive element array including a first sub-array located at a first side of the first feed pole and a second sub-array located at a second side of the first feed pole opposite the first side; 10. A base station antenna comprising: a reflector; a radiator located forward of the reflector; and a dielectric substrate located between the radiator and the reflector and having disposed thereon a conductive element array, wherein each of the conductive elements of the conductive element array includes a conductive trace having a substantially circular outer profile. ​

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