Patent Grant
11489254
The present application is a 35 USC § 371 US national stage application of PCT/US2019/045605, filed Aug. 8, 2019, which claims the benefit of and priority to Chinese Patent Application No. 201810977339.5, filed Aug. 27, 2018, the contents of which are incorporated herein by reference.
The present disclosure generally relates to communications systems and, more particularly, feed networks for antennas.
A base station antenna may include a radiating element, a phase shifter, an electrical tilt control unit and a reflector. In order to reduce interference, the radiating element is disposed on a first side (e.g., the upper side) of the reflector, while the phase shifter and the electrical tilt control unit are disposed on a second side (e.g., the lower side) of the reflector. The radiating element may be coupled to the phase shifter through a jumper cable.
According to a first aspect of the present invention, a feed network is provided. The feed network may comprise: an adjustable electromechanical phase shifter that comprises a main printed circuit board and a phase shifting unit, where the adjustable electromechanical phase shifter is configured to shift the phase of a radio frequency (“RF”) signal that is input to the feed network and provide the phase shifted RF signal to at least one radiating element that is positioned on a first side of a reflector of an antenna. The phase shifting unit is formed on the surface of a first side of the main printed circuit board, where the first side of the main printed circuit board is a side that is closer to the at least one radiating element, and the main printed circuit board is positioned on the first side of the reflector.
According to a second aspect of the present invention, an antenna is provided. The antenna may comprise a reflector, a feed network and at least one radiating element that is positioned on a first side of the reflector, where the feed network comprises an adjustable electromechanical phase shifter that includes a main printed circuit board and a phase shifting unit. The adjustable electromechanical phase shifter is configured to shift the phase of an RF signal that is input to the feed network and provide the phase shifted RF signal to the at least one radiating element. The phase shifting unit is formed on the surface of a first side of the main printed circuit board, where the first side of the main printed circuit board is a side that is closer to the at least one radiating element, and the main printed circuit board is positioned on the first side of the reflector.
in some cases the same elements or elements having similar functions are denoted by the same reference numerals in different drawings, and description of such elements is not repeated. In some cases, similar reference numerals and letters are used to refer to similar elements, and thus once an element is defined in one figure, it need not be further discussed with reference to subsequent figures.
In order to facilitate understanding, the position, size, range, or the like of each structure illustrated in the drawings may not be drawn to scale. Thus, the disclosure is not necessarily limited to the position, size, range, or the like as disclosed in the drawings.
The present invention will be described with reference to the accompanying drawings, which show a number of example embodiments thereof. It should be understood, however, that the present invention can be embodied in many different forms, and is not limited to the embodiments described below. Rather, the embodiments described below are intended to make the disclosure of the present invention more complete and fully convey the scope of the present invention to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in any way to provide many additional embodiments. For the sake of brevity and/or clarity, well-known functions or structures may be not described in detail.
Herein, when an element is described as located “on” “attached” to, “connected” to, “coupled” to or “in contact with” another element, etc., the element can be directly located on, attached to, connected to, coupled to or in contact with the other element, or there may be one or more intervening elements present. In contrast, when an element is described as “directly” located “on”, “directly attached” to, “directly connected” to, “directly coupled” to or “in direct contact with” another element, there are no intervening elements present. In the description, references that a first element is arranged “adjacent” a second element can mean that the first element has a part that overlaps the second element or a part that is located above or below the second element.
Herein, terms such as “upper”, “lower”, “left”, “right”, “front”, “rear”, “high”, “low” may be used to describe the spatial relationship between different elements as they are shown in the drawings. It should be understood that in addition to orientations shown in the drawings, the above terms may also encompass different orientations of the device during use or operation. For example, when the device in the drawings is inverted, a first feature that was described as being “below” a second feature can be then described as being “above” the second feature. The device may be oriented otherwise (rotated 90 degrees or at other orientation), and the relative spatial relationship between the features will be correspondingly interpreted.
Herein, the term “A or B” used through the specification refers to “A and B” and “A or B” rather than meaning that A and B are exclusive, unless otherwise specified
The term “exemplary”, as used herein, means “serving as an example, instance, or illustration”, rather than as a “model” that would be exactly duplicated. Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the detailed description.
Herein, the term “substantially”, is intended to encompass any slight variations due to design or manufacturing imperfections, device or component tolerances, environmental effects and/or other factors. The term “substantially” also allows for variation from a perfect or ideal case due to parasitic effects, noise, and other practical considerations that may be present in an actual implementation.
Herein, certain terminology, such as the terms “first”, “second” and the like, may also be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, the terms “first”, “second” and other such numerical terms referring to structures or elements do not imply a sequence or order unless clearly indicated by the context.
Further, it should be noted that, the terms “comprise”, “include”, “have” and any other variants, as used herein, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.
Referring to
The phase shifting unit 20 is printed on the surface of a first side of the main printed circuit board, wherein the first side of the main printed circuit board is a side that is closer to the at least one radiating element, and the main printed circuit board and the at least one radiating element are positioned on a first side of a reflector (not shown, refer to reference numeral 1 in
The feed network further includes an RF signal input port 10, a phase shifting unit 20, power dividing units 40, 50, 80, conductive traces 31, 32, 33, 34, 35, a low-pass filter 70, and a direct current signal (and/or low frequency signal) output port 60. Each of these elements of the feed network may be formed on the surface of the first side of the main printed circuit board.
The RF signal input port 10 is configured to receive an RF signal from, for example, a radio. The first conductive trace 31 couples the RF signal input port to the phase shifting unit 20 so as to pass the RF signal to the phase shifting unit 20. The phase shifting unit 20 includes an inlet 21 that is configured to input an RF signal into a central coupling region 24, the central coupling region 24, a phase shifting circuit 25, a first outlet 22, and a second outlet 23. As will be understood by those of skill in the art, a wiper arm printed circuit board may be pivotally mounted to the main printed circuit board in the central coupling region 24. An RF signal input at the inlet 21 may pass to the wiper arm printed circuit board and may be passed back to the phase shifting circuit 25 on the main printed circuit board. The RF signal may be split into two sub-components as it is passed to the phase shifting circuit 25. The phase shifting circuit 25 may be configured to shift the respective phases of the two sub-components of the RF signal and to pass the phase shifted sub-components of the RF signal to the first outlet 22 and the second outlet 23, respectively. The first outlet 22 and the second outlet 23 are configured to output the respective sub-components of the phase-shifted RF signals. The sub-components of the phase-shifted RF signals that are output through the first outlet 22 and the second outlet 23 are fed to the at least one radiating element.
The first power dividing unit 40 is a three-port network that includes a first port 41, a second port 42 and a third port 43, and the second power dividing unit 80 is also a three-port network that includes a first port 81, a second port 82 and a third port 83. The second conductive trace 32 couples the first outlet 22 to the first port 41 of the first power dividing unit 40 so that the second port 42 and the third port 43 of the first power dividing unit 40 feed the first sub-component of the phase-shifted RF signal to a first radiating element and a second radiating element, respectively. The third conductive trace 33 couples the second outlet 23 to the first port 81 of the second power dividing unit 80, so that the second port 82 and the third port 83 of the second power dividing unit 80 feed the second sub-component of the phase-shifted RF signal to a third radiating element and a fourth radiating element, respectively. The at least one radiating element may comprise, for example, a linear array of radiating elements of an antenna. Those skilled in the art should appreciate that the First power dividing unit 40 and the second power dividing unit 80 may each include more than two ports, and may also be other suitable sorts of power dividing units not limited to T-junction power dividers, Wilkinson power dividers, etc.
To reduce interference at the radiating elements, some components of a conventional feed network (e.g., a phase shifting unit, a power dividing unit and the like) may be formed on the surface of a second side (e.g., a side that is far away from the radiating elements) of a main printed circuit board where the radiating elements are located on a first side of a reflector of the antenna and the main printed circuit board is located on a second side of the reflector. The feed network feeds RF signals that are to be transmitted by the antenna to the radiating elements, which are located on the first side of the reflector, through jumper cables. Since the feed network according to embodiments of the present invention may be formed on the surface of the first side (e.g., a side that is closer to the radiating elements) of the main printed circuit board, and the main printed circuit board and the radiating elements are all located on the first side of the reflector, space on the second side of the reflector may be saved, which is advantageous for miniaturization of the antenna. Moreover, in the feed network according to embodiments of the present invention, the electrical coupling between various portions of the feed network is achieved with conductive traces instead of using jumper cables, which is beneficial to reducing interference to the radiating elements and which may also reduce the number of locations where passive intermodulation distortion (PIM) may be generated.
In addition, since the main printed circuit board and the at least one radiating element are both located on the first side of the reflector, the conductive traces on the main printed circuit board may radiate RF energy outwardly, and the radiated energy may affect the at least one radiating element. To reduce RF energy radiating from the conductive traces on the main printed circuit board, at least one of the following measures may be taken: providing metallized vias, for example, the metallized vias may be provided in the main printed circuit board at a position that is close to a portion of a conductive trace in the feed network, where a current with a value greater than a threshold may flow through the portion of the conductive trace; increasing the area of the reference ground, for example, in the case that the conductive traces are printed on the first surface of the main printed circuit board and a grounded conductor is printed on the second surface of the main printed circuit board, an additional conductor may be printed on the first surface of the main printed circuit board, and the additional conductor printed on the first surface of the main printed circuit board may be electrically connected to the grounded conductor printed on the second surface of the main printed circuit board.
In some embodiments, the feed network is further configured to feed another sub-component of the RF signal that is input at RF signal input port 10 to a fifth radiating element of the antenna. For example, in some embodiments, the feed network may feed a sub-component of the RF signal that is input at RF signal input port 10 to the fifth radiating element via the RF signal input port 10, the first conductive trace 31 and a fifth conductive trace 35. A first end of the first conductive trace 31 is coupled to the RF signal input port 10, and a first end of the fifth conductive trace 35 is coupled to a second end of the first conductive trace 31. The second end of the fifth conductive trace 35 may feed the sub-component of the RF signal to the fifth radiating element.
In some embodiments, the feed network may feed power to the fifth radiating element via the RF signal input port 10, the first conductive trace 31, the fifth conductive trace 35 and the third power dividing unit 50. As shown in
In some embodiments, the feed network may further be configured to output a direct current signal and/or a low frequency signal. The RF signal input port 10 is further configured to input a direct current (or low frequency) signal, for example, together with an RF signal, to the feed network. The low-pass filter 70 is configured to filter at least part of a signal that is input to the feed network at the RF signal input port 10 to pass the direct current signal (and/or low frequency signal) to the direct current signal output port 60. The direct current signal output port 60 outputs the direct current signal (and/or low frequency signal) from the feed network. A first end of the fourth conductive trace 34 is coupled to the first port 51 of the third power dividing unit 50, and a second end of the fourth conductive trace 34 is coupled to the direct current signal output port 60. The low-pass filter 70 is coupled to the fourth conductive trace 34 between the first end and the second end of the fourth conductive trace 34 such that the second end of the fourth conductive trace 34 outputs any direct current signal or low frequency signal to the direct current signal output port 60.
The feed network according to embodiments of the present invention may pass signals from the RF signal input port 10 to the third power dividing unit 50 via the first conductive trace 31 and the fifth conductive trace 35. After power dividing by the third power dividing unit 50, a first portion of the signals is passed to the low-pass filter 70 via the fourth conductive trace 34. The low-pass filter 70 filters the signals and passes any direct current signal and/or low frequency signal in the first portion of the signals to the direct current signal output port 60 via the fourth conductive trace 34, such that the direct current signal and/or low frequency signal may be utilized, for example, directly by an electrical tilt control unit of the antenna without any additional processing. A second portion of the signals is fed to one or more radiating elements of the antenna via the third port 53 of the third power dividing unit 50. The low-pass filter 70 shown in the drawings is merely an example, and those skilled in the art should appreciate that the low-pass filter 70 can be any low-pass filter with an appropriate structure, such as an elliptic function filter, a step impedance resonator, etc. By appropriately designing the fourth conductive trace 34 and the low-pass filter 70 and other components, the amount of isolation between the direct current signal (and/or low frequency signal) output by the feed network and the RF signal transmitted in the feed network may meet a design requirement such as, for example, greater than 50 dB of isolation.
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, the first conductive trace 31 and the second conductive trace 32 on the first side of the phase shifting unit 20 are arranged such that the strength of signal coupling between the first conductive trace 31 and the second conductive trace 32 meets a design requirement, e.g., lower than a first threshold (which may be −20 dB, for example). The third conductive trace 33 and the fourth conductive trace 34 on the second side of the phase shifting unit 20 are arranged such that the strength of signal coupling between the third conductive trace 33 and the fourth conductive trace 34 meets a design requirement, e.g., lower than a second threshold (which may be −20 dB, for example). In this way, the feed network may ensure that the strength of signal coupling between the conductive traces meets design requirements while the structure is compact and the space is saved.
In the feed network according to each of the above embodiments of the present invention, the bends in the conductive traces, the power dividing units, the phase shifting unit, the filter and the like may all be rounded, which may be beneficial to improving the PIM performance of the feed network. Appropriate adjustment of the size of each conductive trace helps to perform impedance matching, so that the return loss performance of the feed network may meet a design requirement.
The feed network according to each of the above embodiments of the present invention not only realizes the function of feeding power to radiating elements of the antenna, but more importantly, multiple functions including feeding the radiating elements, phase shifting, filtering, and providing power directly to an electrical tilt control unit are integrated on a single main printed circuit board, which saves space as compared to conventional feed networks, and is advantageous for miniaturization of the antenna.
In some embodiments, the first power dividing unit 40 and the second power dividing unit 80 in each of the feed networks 200 and 300 in the antenna are respectively located on the two opposite sides of the phase shifting unit 20, so that feeding power to the radiating elements arranged along a line becomes easy while the structure of the antenna is compact. In the case of such an arrangement of the first power dividing unit 40 and the second power dividing unit 80, the inlet 21 of the phase shifting unit 20, the first conductive trace 31 and the RF signal input port 10 may be arranged on the first side of the phase shifting unit 20 (for example, in the direction shown in the drawings, on the right side of the phase shifting unit 20), and the third power dividing unit 50, the fourth conductive trace 34, the low-pass filter 70 and the direct current signal output port 60 are arranged on the second side of the phase shifting unit 20 (for example, in the direction shown in the drawings, on the left side of the phase shifting unit 20) that is opposite the first side, so that the structure of the antenna is further compact. Those skilled in the art may appreciate that the drawings are merely exemplary, in the direction shown in the drawings, the first side may also be the left side, the upper side or the lower side of the phase shifting unit 20, and the second side may also be correspondingly the right side, the lower side or the upper side of the phase shifting unit 20.
In some embodiments, as shown in
Each of the radiating elements 6 may be coupled to the feed network, for example, coupled to a respective port of the power dividing unit without the use of a jumper cable. Each of the at least one radiating element 6 comprises a radiator 5 and a feed stalk 4, wherein the radiator 5 is mounted to the main printed circuit board 2 through the feed stalk 4. For example, the radiator 5 of the radiating element 6 is mounted to the feed stalk 4, and the feed stalk 4 is mounted (for example by welding) to the main printed circuit board 2. In addition, conductors in the radiator 5 are also coupled to the feed network through conductors in the feed stalk 4, so that the feed network may feed RF signals that are to be transmitted by the antenna to the radiator 5. For example, referring again to
In some embodiments, the antenna of the present invention further includes an electrical tilt control unit 7 that is positioned on a second side of the reflector 1 that is opposite the first side, wherein the electrical tilt control unit 7 is configured to control movement of the wiper arm printed circuit board 3. Referring to
Although some specific embodiments of the present invention have been described in detail with examples, it should be understood by a person skilled in the art that the above examples are only intended to be illustrative but not to limit the scope of the present invention. The embodiments disclosed herein can be combined arbitrarily with each other, without departing from the scope and spirit of the present invention. It should be understood by a person skilled in the art that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201810977339.5 | Aug 2018 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/045605 | 8/8/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/046550 | 3/5/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 7298233 | Zimmerman | Nov 2007 | B2 |
| 8674788 | Le | Mar 2014 | B2 |
| 9431703 | Dandlberger | Aug 2016 | B1 |
| 20090213020 | Rentz et al. | Aug 2009 | A1 |
| 20100157858 | Lee et al. | Jun 2010 | A1 |
| 20110241954 | Le | Oct 2011 | A1 |
| 20120319909 | Irmscher | Dec 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| 210926307 | Jul 2020 | CN |
| 2017177927 | Oct 2017 | WO |
| WO-2017177927 | Oct 2017 | WO |
| Entry |
|---|
| International Search Report and the Written Opinion of the International Searching Authority corresponding to International Patent Application No. PCT/US2019/045605 (8 pages) (dated Nov. 1, 2019). |
| Number | Date | Country | |
|---|---|---|---|
| 20210242583 A1 | Aug 2021 | US |
