Patent Application
20230344123
The present application claims the benefit of priority to Chinese Patent Application No. 202210446082.7, filed on Apr. 26, 2022, with the China National Intellectual Property Administration, and the entire contents of the above-identified application are incorporated by reference herein.
The present disclosure generally relates to base station antennas, and more specifically, to a radio frequency device, a multi-band phase shifter assembly, an antenna system, and a base station antenna.
Cellular communications systems are well known in the art. In a cellular communications system, a geographic area is divided into a series of sections that are referred to as “cells” which are served by respective base stations. The base station may include one or more base station antennas that are configured to provide two-way radio frequency (“RF”) communications with mobile subscribers that are within the cell served by the base station.
In order to accommodate the ever-increasing volumes of cellular communications, cellular operators have added cellular services in a variety of new frequency bands. In some cases, it is possible to use linear arrays of so-called “wide-band” or “ultra wide-band” radiating elements to provide service in multiple frequency bands. For example, a radiating element operating within a frequency range of 1.7 to 2.7 GHz can be used to support cellular services in multiple different frequency bands that are at least partially within the frequency range. Base station antennas may also typically include multiple radiating element arrays that are designed to operate in different frequency bands. For example, in a common multi-band antenna system, the antenna may have at least one linear array of one or more “low-band” radiating elements providing service in some or all of 617 to 960 MHz frequency bands (for example, Digital Dividend and/or GSM900 at 790 to 862 MHz) and at least one linear array of “medium-band” radiating elements providing service in some or all of, for example, 1427 to 2690 MHz frequency bands (for example, UTMS and/or GSM1800 at 1920 to 2170 MHz). However, the multi-band antenna often has an increased width to accommodate the increased number of radiating element arrays. Due to local zoning ordinances and/or weight/wind loading constraints for antenna towers, there are often limitations on the sizes of base station antennas that can be deployed at a given base station. These constraints may effectively limit the number of radiating element arrays that may be included in the multi-band antenna.
Most modern multi-band antennas include phase shifters that are used to adjust the down tilt angle of the radiation patterns or “antenna beams” generated by the radiating element arrays. Such down tilt angle adjustment may be used to adjust the coverage area of each radiating element array.
However, with the integration of more and more frequency bands and more and more functional modules (for example, phase shifters, filters, coaxial cables and radiating element arrays, etc.) in the base station antenna, the installation space and/or operation space (such as welding space) in the base station antenna is further restricted. This causes the design size of some radio frequency devices, for example, phase shifters or filters, to be subject to strict restrictions. A limited design size may result in smaller gaps between transmission lines within the radio frequency device, creating coupling interference between transmission lines that may negatively affect radio frequency performance of the radio frequency device. This is undesirable.
An object of the present disclosure (but not the only object of the present disclosure) is to provide a radio frequency device, a multi-band phase shifter assembly, an antenna system, and a base station antenna that are capable of overcoming at least one of the defects in the prior art.
According to a first aspect of the present disclosure, a radio frequency device is provided, and the radio frequency device may include: a substrate; a first transmission line printed on a first major surface of the substrate; a second transmission line adjacent the first transmission line and printed on the first major surface of the substrate; a metasurface decoupling element printed on the first major surface of the substrate, where the metasurface decoupling element is arranged between the first transmission line and the second transmission line.
According to a second aspect of the present disclosure, a multi-band phase shifter assembly is provided, and the multi-band phase shifter assembly may include: a first phase shifter, configured to perform a phase shift operation on sub-components of a first radio frequency signal in a first frequency band; a second phase shifter, configured to perform a phase shift operation on sub-components of a second radio frequency signal in a second frequency band, the second frequency band being different from the first frequency band; and a plurality of first filters which are configured to pass the first radio frequency signal while blocking the second radio frequency signal, where an input of each first filter is connected to a corresponding output port of the first phase shifter. The multi-band phase shifter assembly may also include a plurality of second filters which are configured to pass a second radio frequency signal while blocking the first radio frequency signal, where an input of each second filter is connected to a corresponding output port of the second phase shifter; a first metasurface decoupling element, arranged within a first gap between two adjacent first filters; and a second metasurface decoupling element, arranged within a second gap between two adjacent second filters.
According to a third aspect of the present disclosure, an antenna system is provided, and the antenna system may include a multi-band phase shifter assembly according to some embodiments of present disclosure; a radiating element array, which is configured to operate in at least a first frequency band and a second frequency band, wherein a common output port of the multi-band phase shifter assembly is electrically connected with at least a part of the radiating elements in the radiating element array.
According to a fourth aspect of the present disclosure, a base station antenna is provided, the base station antenna includes the radio frequency device according to some embodiments of present disclosure or includes the antenna system according to some embodiments of present disclosure.
The above and other aspects and objects of the present disclosure will be described herein, and/or will be apparent based on the description provided herein.
The present disclosure will be explained in greater detail by means of specific embodiments with reference to the attached drawings. The drawings are briefly described as follows:
The present disclosure will be described below with reference to the attached drawings, which illustrate certain embodiments of the present disclosure. However, it should be understood that the present disclosure may be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present disclosure more complete and to fully explain the protection scope of the present disclosure to those of ordinary skill in the art. It should also be understood that the embodiments disclosed in the present disclosure may be combined in various ways so as to provide more additional embodiments.
It should be understood that the terms used herein are only used to describe specific embodiments, and are not intended to limit the scope of the present disclosure. All terms used herein (including technical terms and scientific terms) have meanings normally understood by those skilled in the art unless otherwise defined. For brevity and/or clarity, well-known functions or structures may not be further described in detail.
As used herein, when an element is said to be “on” another element, “attached” to another element, “connected” to another element, “coupled” to another element, or “in contact with” another element, etc., the element may be directly on another element, attached to another element, connected to another element, coupled to another element, or in contact with another element, or an intermediate element may be present. In contrast, if an element is described as “directly” “on” another element, “directly attached” to another element, “directly connected” to another element, “directly coupled” to another element or “directly in contact with” another element, there will be no intermediate elements. As used herein, when one feature is arranged “adjacent” to another feature, it may mean that one feature has a part overlapping with the adjacent feature or a part located above or below the adjacent feature.
As used herein, spatial relationship terms such as “upper,” “lower,” “left,” “right,” “front,” “back,” “high,” and “low” can explain the relationship between one feature and another in the drawings. It should be understood that, in addition to the orientations shown in the attached drawings, the terms expressing spatial relations also comprise different orientations of a device in use or operation. For example, when a device in the attached drawings rotates reversely, the features originally described as being “below” other features now can be described as being “above” the other features″. The device may also be oriented by other means (rotated by 90 degrees or at other locations), and at this time, a relative spatial relation will be explained accordingly.
As used herein, the term “A or B” comprises “A and B” and “A or B,” not exclusively “A” or “B,” unless otherwise specified.
As used herein, the term “schematic” or “exemplary” means “serving as an example, instance or explanation,” not as a “model” to be accurately copied″. Any realization method described exemplarily herein may not be necessarily interpreted as being preferable or advantageous over other realization methods.
As used herein, the word “basically” means including any minor changes caused by design or manufacturing defects, device or component tolerances, environmental influences, and/or other factors.
In addition, for reference purposes only, “first,” “second” and similar terms may also be used herein, and thus are not intended to be limitative. For example, unless the context clearly indicates, the words “first,” “second” and other such numerical words involving structures or elements do not imply a sequence or order.
It should also be understood that when the term “comprise/include” is used herein, it indicates the presence of the specified feature, entirety, step, operation, unit and/or component, but does not exclude the presence or addition of one or a plurality of other features, steps, operations, units and/or components and/or combinations thereof.
The present disclosure proposes a radio frequency device, which may be realized as a printed circuit board, which may include a dielectric substrate, a first transmission line and a second transmission line printed on a first major surface of the substrate, and a metasurface decoupling element printed between the first transmission line and the second transmission line. The metasurface decoupling element may be configured to at least partially reduce undesirable coupling between the first transmission line and the second transmission line, thereby improving radio frequency performance of the radio frequency device. When the coupling between the first transmission line and the second transmission line is capacitive coupling, the metasurface decoupling element may be configured as an inductive decoupling element at least within the operating frequency band of the radio frequency device so as to at least partially cancel the capacitive coupling between the first transmission line and the second transmission line. When the coupling between the first transmission line and the second transmission line is inductive coupling, the metasurface decoupling element may be configured as a capacitive decoupling element at least within the operating frequency band of the radio frequency device so as to at least partially cancel the inductive coupling between the first transmission line and the second transmission line.
The metasurface decoupling element may include or be configured as a plurality of periodically arranged metal pattern units. The frequency characteristics of the metasurface decoupling element may be adjusted by changing the shape, number, and/or arrangement of the metal pattern units in order to better adapt to the coupling characteristics between the first transmission line and the second transmission line.
It should be understood that the radio frequency device of the present disclosure may be a variety of functional devices applied in base station antennas, and is not limited to the type of devices described in specific embodiments. In some embodiments, the radio frequency device may be a phase shifter or a power divider. In other example embodiments, the radio frequency device may be a filter, a duplexer, a combiner, a feed board or the like.
Next, the radio frequency device of some embodiments of the present disclosure is described in detail using a multi-band phase shifter assembly as an example.
As shown in
Each phase shifter 110, 130, 110′, and 130′ in the multi-band phase shifter assemblies 100 and 100′ according to first and second embodiments of the present disclosure may be configured as a variable differential, arcuate phase shifter or a rotary wiper arm phase shifter as described in U.S. Pat. No. 7,907,096 (incorporated into the present disclosure by reference). In the corresponding arcuate phase shifter, a rotatable wiper arm couples sub-components of an RF signal to selected positions along one or more fixed arc-shaped transmission lines.
Unlike the multi-band phase shifter assembly 100′ according to the embodiment of
Next, this superimposed structure of the multi-band phase shifter assembly 100 of the second embodiment of the present disclosure will be described in detail with reference to
As shown in
As shown in
Each phase shifter may have, for example, 5, 7, 9 or more output ports. In the illustrated embodiment, the phase shifter has 7 output ports, of which 6 are differentially variably phase-shifted and 1 maintains an output of a fixed phase. However, an output that has a fixed phase relation with the input is optional. As a result, the first phase shifter 110 and the second phase shifter 130 may respectively perform 1:7 of power distribution along the radio transmission direction (i.e., each phase shifter 110, 130 may divide radio frequency signals input thereto into seven sub-components, which may or may not have the same magnitude). In other embodiments, the first phase shifter 110 and the second phase shifter 130 may also respectively perform, for example, 1:5 or 1:9 or other ratios (including even ratios) of power distribution along the radio transmission direction. However, with the phase shifters 110, 130 integrated with more output ports, the limited wiring space on the printed circuit board becomes more compact, thereby narrowing the gap between the transmission lines.
In addition to a phase shift circuit, each phase shifter printed circuit board further includes a filter bank that includes a plurality of individual filters. As shown in
In the illustrated embodiment, the first filter bank 120 and the second filter bank 140 may be printed as filter microstrip lines (for example, resonant stubs, or stepped impedance microstrip lines) on corresponding circuit printed boards and printed integrally with corresponding phase shift circuits. In other words, the first rotary wiper arm phase shifter 110 and the corresponding first filter bank 120 may be integrated on a first printed circuit board, and the second rotary wiper arm phase shifter 130 and the corresponding second filter bank 140 may be integrated on a second printed circuit board. Such an integration structure is advantageous in that it can simplify the composition of the antenna system and can also save space. For example, unnecessary cable connections can be omitted.
The first filter bank 120 may be configured to pass the sub-components of the first radio frequency signal while blocking the sub-components of the second radio frequency signal, and the second filter 140 may be configured to pass the sub-components of the second radio frequency signal while blocking the sub-components of the first radio frequency signal. In some embodiments, the first filter bank 120 and the second filter bank 140 may be respectively configured as band-rejection filters. In some embodiments, the first filter bank 120 and the second filter bank 140 may be respectively configured as band-pass filters.
In the illustrated embodiment, each corresponding filter may be formed by providing one or more resonant stubs along a transmission line, which can be used as a band-rejection filter to block energy in a specific frequency band. The resonant frequency mainly depends on the length of the stub(s) and how the stub(s) is/are terminated, for example, a quarter-wavelength open stub or a half-wavelength short-circuit stub.
It should be understood that those skilled in the art can easily recognize other types of filters, which can be used without departing from the scope and spirit of the present disclosure. In some embodiments, the filters may be configured separately from the phase shifter and may be electrically connected with each other via a coaxial cable. In some embodiments, the first filter bank 120 and/or the second filter bank 140 may be configured as notch filters, respectively. In some embodiments, the first filter bank 120 and/or the second filter bank 140 may be configured as cavity filters, respectively. Details are not described herein again.
Referring to
Continuing to refer to
It should be understood that those skilled in the art can easily recognize other types of conductive structures 126, which can be used without departing from the scope and spirit of the present disclosure. In some embodiments, the conductive structure 126 may be configured as a coaxial connector.
The above superimposed structure of the multi-band phase shifter assembly 100 is advantageous. The wiring flexibility of each phase shifter 110, 130 along with the corresponding filter banks 120, 140 may be improved. In addition, based on wiring flexibility, welding ends 122 for the coaxial cables 134 may be provided at lateral edges of the multi-band phase shifter assembly 100, thereby facilitating the welding operation. Further, based on this superimposed structure, the width of the multi-band phase shifter assembly 100 may be significantly reduced, for example, by at least half compared to the embodiment of
However, such a compact design size may cause the distance between the transmission lines of the multi-band phase shifter assembly 100, for example, the gap between filter branches, to become smaller, thereby creating coupling interference between adjacent transmission lines, for example, filtering branches, which may negatively affect the radio frequency performance of the multi-band phase shifter assembly 100, for example, the down tilt angle adjustment performance. In some cases, although a portion of coupling interference may be reduced by rewiring, this may negatively impact filter performance and/or return loss performance. Furthermore, in some cases, the coupling interference may be partially reduced by providing slots on the ground layer, but this may in turn result in a risk of leakage of RF signal.
As a result, the multi-band phase shifter assembly 100 of the present disclosure may include: one or a plurality of first metasurface decoupling elements 81, each of which may be printed within a gap between two adjacent filters of the first filter bank 120; one or a plurality of second metasurface decoupling elements 82, each seond metasurface decoupling element 82 may be printed within a gap between two adjacent filters of the second filter bank 140.
It should be understood that corresponding metasurface decoupling elements 81′ and 82′ may be provided between adjacent filters in the multi-band phase shifter assembly 100 of the second embodiment, and also the multi-band phase shifter assembly 100′ of the first embodiment, as shown in
Continuing to
It should be understood that the corresponding metasurface decoupling elements need not be provided between every pair of adjacent filters, but only for those pairs of filters having large coupling interferences and/or narrow gaps therebetween. For example, when the coupling interference between two adjacent filters exceeds a predetermined threshold, a metasurface decoupling element may be printed therebetween. For example, when the gap between two adjacent filters is smaller than a predetermined value, for example, 10 mm, 8 mm, 6 mm, 4 mm or 2 mm or even 1 mm, the corresponding metasurface decoupling element may be printed therebetween.
Each metasurface decoupling element may include or be configured as a plurality of periodically arranged metal pattern units. The frequency characteristics of the metasurface decoupling element may be adjusted by changing the shape, number, and/or arrangement of the metal pattern units.
To adapt to the frequency characteristics of the filters of the first filter bank 120, the first metasurface decoupling elements 81 may be configured to present decoupling characteristics at least within the first operating frequency band. To adapt to the frequency characteristics of the filters of the second filter bank 140, the second metasurface decoupling elements 82 may be configured to present decoupling characteristics at least within the second operating frequency band.
When the coupling between two adjacent filters of the first filter bank 120 is inductive coupling/capacitive coupling, the first metasurface decoupling elements 81 may be configured as capacitive decoupling elements/inductive decoupling elements at least within the first operating frequency band, so as to at least partially cancel the inductive coupling/capacitive coupling between the two filters. When the coupling between two adjacent filters of the second filter bank 140 is inductive coupling/capacitive coupling, the second metasurface decoupling elements 82 may be configured as capacitive decoupling elements/inductive decoupling elements at least within the second operating frequency band so as to at least partially cancel the inductive coupling/capacitive coupling between the two filters.
In some embodiments, the number, shape and/or arrangement of the metal pattern units of the first metasurface decoupling elements 81 may be configured differently than the number, shape and/or arrangement of the metal pattern units of the second metasurface decoupling elements 82. As shown in
Although exemplary embodiments of the present disclosure have been described, those skilled in the art should understand that many variations and modifications are possible in the exemplary embodiments without materially departing from the spirit and scope of the present disclosure. Therefore, all variations and changes are included in the protection scope of the present disclosure defined by the claims. The present disclosure is defined by the attached claims, and equivalents of these claims are also included.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202210446082.7 | Apr 2022 | CN | national |
