FIELD

[0001] The present disclosure relates to communication systems and, in particular, to phase shifters for base station antennas.

BACKGROUND

[0002] Base station antennas for wireless communication systems are used to transmit Radio Frequency (RF) signals to, and receive RF signals from, fixed and mobile users of a cellular communications service. Base station antennas often include a linear array or a two-dimensional array of radiating elements such as dipole, or crossed dipole, radiating elements. To change the down tilt angle of these antennas, a phase taper may be applied across the radiating elements. Such a phase taper may be applied by adjusting the settings on an adjustable phase shifter that is positioned along an RF transmission path between a radio and the individual radiating elements of the base station antenna.

[0003] One known type of phase shifter is an electromechanical rotating "wiper" arc phase shifter that includes a main Printed Circuit Board (PCB) and a "wiper" PCB that may be rotated above the main PCB. Such a rotating wiper arc phase shifter typically divides an input RF signal that is received at the main PCB into a plurality of sub-components, and then capacitively couples at least some of these sub-components to the wiper PCB. These subcomponents of the RF signal may be capacitively coupled from the wiper PCB back to the main PCB along a plurality of arc-shaped traces, where each arc has a different radius. Each end of each arc-shaped trace may be connected to a radiating element or to a sub-group of radiating elements. By physically rotating the wiper PCB above the main PCB, the location where the sub-components of the RF signal capacitively couple back to the main PCB may be changed, thereby changing the path lengths that the sub-components of the RF signal traverse when passing from a radio to the radiating elements. These changes in the path lengths result in changes in the phases of the respective sub-components of the RF signal, and because the arcs have different radii, the change in phase experienced along each path differs.

[0004] Typically, the phase taper is applied by applying positive phase shifts of various magnitudes (e.g., +1°, +2° and +3°) to some of the sub-components of the RF signal and by applying negative phase shifts of the same magnitudes (e.g., -1°, -2° and -3°) to additional of the sub-components of the RF signal. Thus, the above-described rotary wiper arc phase shifter may be used to apply a phase taper to the sub-components of an RF signal that are transmitted through the respective radiating elements (or sub-groups of radiating elements). Example phase shifters of this variety are discussed in U.S. Patent No. 7,907,096 to Timofeev, the disclosure of which is hereby incorporated herein by reference in its entirety. The wiper PCB is typically moved using an actuator that includes a Direct Current (DC) motor that is connected to the wiper PCB via a mechanical linkage. These actuators are often referred to as "RET" actuators because they are used to apply the remote electronic down tilt.

SUMMARY

[0005] A base station antenna, according to some embodiments herein, may include a metal housing. The base station antenna may include a series of rotary wiper phase shifters in the metal housing. The base station antenna may include a Radio Frequency (RF) transmission line traversing each of the rotary wiper phase shifters in the series. Moreover, the base station antenna may include a linkage connected to each of the rotary wiper phase shifters in the series. The linkage may be configured to simultaneously adjust each of the rotary wiper phase shifters in the series by an equal amount.

[0006] In some embodiments, the base station antenna may include a main Printed Circuit Board (PCB) having the RF transmission line thereon. The series of rotary wiper phase shifters may include a plurality of wiper phase shifter PCBs that are in a linear array on the main PCB. Moreover, the main PCB may have a single RF input and a plurality of RF outputs.

[0007] A base station antenna, according to some embodiments herein, may include a metal housing and a main Printed Circuit Board (PCB) in the metal housing. Moreover, the base station antenna may include a linear array of phase shifters that includes a plurality of wiper phase shifter PCBs that are collinear on the main PCB.

[0008] In some embodiments, the base station antenna may include a plurality of flexible components between a surface of the metal housing and the plurality of wiper phase shifter PCBs, respectively. The plurality of wiper phase shifter PCBs may be between the main PCB and the surface of the metal housing.

[0009] According to some embodiments, the base station antenna may include a transmission line on a first side of the main PCB that faces the plurality of wiper phase shifter PCBs. Moreover, the base station antenna may include a support structure on a second side of the main PCB that is opposite the first side. The support structure may include a first tab that extends through an opening in the main PCB and contacts the metal housing. Moreover, the support structure may include a second tab that contacts the main PCB and a side surface of the metal housing. Additionally or alternatively, the support structure may include a ribbed plastic support structure that includes a plurality of arcs.

[0010] In some embodiments, the base station antenna may include a spacer that is attached to the main PCB and that extends to the metal housing. Moreover, respective conductive traces on the plurality of wiper phase shifter PCBs may have rounded corners. Additionally or alternatively, each of the plurality of wiper phase shifter PCBs may have a respective single arcuate conductive trace.

[0011] According to some embodiments, the base station antenna may include a linkage that is connected to each of the plurality of wiper phase shifter PCBs. Moreover, the base station antenna may include a removable structure including a first portion that is attachable to the main PCB and a second portion that is attachable to the linkage. The removable structure may be a removable plastic structure that includes a plurality of holes therein.

[0012] A base station antenna may include a Radio Frequency (RF) shield and a series of phase shifters in the RF shield. The series of phase shifters may be configured to provide a plurality of different phase-shifted RF output values and to simultaneously adjust each of the plurality of different phase-shifted RF output values by an identical amount. The RF shield may be an extruded aluminum housing.

[0013] In some embodiments, the base station antenna may include a main Printed Circuit Board (PCB), and the series of phase shifters may include a plurality of wiper phase shifter PCBs that are in a linear array on the main PCB. Moreover, the base station antenna may include a mechanical linkage that is connected to each of the plurality of wiper phase shifter PCBs, and each of the plurality of wiper phase shifter PCBs may include a respective single curved conductive trace.

[0014] The main PCB may include a curved conductive trace that is configured to provide an RF transmission line coupled to the plurality of wiper phase shifter PCBs. In some embodiments, the main PCB may include first and second RF transmission lines coupled to the series of phase shifters. Moreover, the plurality of phase shifter PCBs may be a plurality of rotary wiper phase shifter PCBs, respectively. Each of the plurality of rotary wiper phase shifter PCBs may include a respective conductive trace having a portion that conforms to a shape of the curved conductive trace of the main PCB. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 A is a schematic block diagram of a phase shifter assembly for a base station antenna that includes serially-arranged individual phase shifters according to embodiments of present inventive concepts.

[0016] FIG. 1 B is a front view of a main printed circuit board that may be used with serial phase shifters according to embodiments of present inventive concepts. Moreover, FIG. 1G is a front view of a main printed circuit board having two conductive arcs according to embodiments of present inventive concepts.

[0017] FIG. 1C is a front view of phase shifter printed circuit boards according to embodiments of present inventive concepts.

[0018] FIG. 1 D is a plan view of a housing for serial phase shifters according to embodiments of present inventive concepts.

[0019] FIG. IE is a side view of the housing of FIG. ID.

[0020] FIG. IF is a schematic block diagram of a base station antenna that includes a phase shifter assembly according to embodiments of present inventive concepts.

[0021] FIG. 2A is a front view of a support structure that may be used with a main printed circuit board according to embodiments of present inventive concepts.

[0022] FIG. 2B is a perspective view of the support structure of FIG. 2 A.

[0023] FIG. 2C is a front view of a support structure that may be used with a main printed circuit board according to embodiments of present inventive concepts.

[0024] FIG. 2D is a perspective view of the support structure of FIG. 2C.

[0025] FIG. 3 A is a rear view of a main printed circuit board, and a support structure thereon, that may be used with serial phase shifters according to embodiments of present inventive concepts.

[0026] FIG. 3B is an enlarged view of FIG. 3A.

[0027] FIG. 4A is a view of one side of a removable structure that is attachable to a main printed circuit board and to a linkage for serial phase shifters according to embodiments of present inventive concepts.

[0028] FIG. 4B is a view of an opposite side of the removable structure of FIG. 4A.

[0029] FIG. 4C is a view of the removable structure of FIG. 4B while attached to a linkage for serial phase shifters. Moreover, FIG. 4D is a view of a removable structure having three protruding portions according to embodiments of present inventive concepts, and FIG. 4E is a view of openings in a main printed circuit board that are configured to receive the removable structure of FIG. 4D. [0030] FIG. 5 A is a perspective view of a spacer that is attachable to a main printed circuit board that may be used with serial phase shifters according to embodiments of present inventive concepts. Moreover, FIG. 5B is a view of openings in a main printed circuit board that are configured to receive the spacer of FIG. 5 A.

[0031] FIG. 6 A is a top perspective view of a housing for serial phase shifters according to embodiments of present inventive concepts.

[0032] FIG. 6B is a top view of the housing of FIG. 6A.

[0033] FIG. 7A is a perspective view of a flexible component that may be used with serial phase shifters according to embodiments of present inventive concepts. Moreover, FIG. 7B is a side view of the flexible component of FIG. 7A attached to a main printed circuit board, and FIG. 7C is a bottom perspective view of the flexible component attached to the main printed circuit board.

[0034] FIG. 8 is a perspective view of a prior art electromechanical rotary wiper arc phase shifter.

DETAILED DESCRIPTION

[0035] Pursuant to embodiments of present inventive concepts, base station antennas are provided that have phase shifter assemblies. Each phase shifter assembly may include a series of individual rotatable phase shifters on the same main (stationary) Printed Circuit Board (PCB). The series of individual phase shifters sharing the main PCB may have a more desirable shape (rectangular) than prior art electromechanical rotary wiper arc phase shifters. The main PCB may be implemented by a flexible PCB, which may provide a phase shifter assembly that is much lighter than prior art electromechanical rotary wiper arc phase shifters. Accordingly, a phase shifter assembly including the series of individual phase shifters on a flexible main PCB may help reduce the weight of the base station antenna. Moreover, the series of individual phase shifters may be uniformly controlled by a common linkage that runs alongside the series of individual phase shifters, to provide an identical amount of adjustment to each of the series of individual phase shifters.

[0036] A base station antenna pursuant to embodiments herein may also include various structures/components that support the series of individual phase shifters and/or the main PCB. These structures/components may help restrict undesired movement of the main PCB, help provide desired spacing in a housing that includes the main PCB, and/or facilitate assembly of the phase shifter assembly. [0037] Example embodiments of present inventive concepts will be described in greater detail with reference to the attached figures.

[0038] FIG. 1 A is a schematic block diagram of a phase shifter assembly 100 for a base station antenna that includes serially-arranged individual phase shifters 120 according to embodiments of present inventive concepts. The series of individual phase shifters 120 is on a single, continuous main PCB 130 that is in a housing 110. A common linkage 140 is connected to each individual phase shifter 120 in the series, and thus is configured to rotate all of the individual phase shifters 120 in the series simultaneously.

[0039] As illustrated by FIG. 1 A, the individual phase shifters 120 in the series may be collinear on the main PCB 130, and thus may be referred to herein as a "linear array." Each individual phase shifter 120 may be a rotary Wiper Phase Shifter (WPS), as indicated in FIG. 1 A, and thus may be referred to herein as a "rotary wiper arc phase shifter," a "rotary wiper arm phase shifter," or a "wiper arm PCB." The individual phase shifters 120 may be rigid, whereas the main PCB 130 may be implemented by a flexible PCB, which may help reduce the weight of the base station antenna.

[0040] Although FIG. 1 A provides an example in which eight individual phase shifters 120 are in the series, the series could include more or fewer phase shifters 120. For example, the series could include two, three, four, five, six, seven, or more individual phase shifters 120. Moreover, each of the individual phase shifters 120 in the series may be implemented as a respective phase shifter PCB that is between the main PCB 130 and a surface of the housing 110, as indicated by the dashed lines in FIG. 1 A.

[0041] The individual phase shifters 120 in the series may optionally be arranged in pairs, where the phase shifters 120 that are in a pair are closer to each other than to any other phase shifter 120 in the series. As an example, the series in FIG. 1A includes three pairs of the phase shifters 120: the rightmost two phase shifters 120, the leftmost two phase shifters 120, and the middle two phase shifters 120. The remaining two individual phase shifters 120 are not part of a pair.

[0042] As would be understood by a person skilled in the art, the phase shifter assembly 100 may be used in a base station antenna that includes radiating elements that are coupled to the phase shifter assembly 100. In particular, the base station antenna may include an array of radiating elements that receives a phase-shifted Radio Frequency (RF) signal that is output by the series of individual phase shifters 120. In some embodiments, the series of individual phase shifters 120 may be configured to provide a plurality of different phase- shifted RF output values to the respective radiating elements or to respective groups of radiating elements. Moreover, the common linkage 140 may be configured to simultaneously shift each of the individual phase shifters 120 to adjust each of the plurality of different phase-shifted RF output values. Specifically, the output of each of the individual phase shifters 120 may be adjusted by the same amount (i.e., a common, uniform adjustment value). For example, the common linkage 140 may rotate each individual phase shifter 120 by the same amount.

[0043] Examples of a base station antenna with a rotary wiper phase shifter coupled to an array of radiating elements are discussed in U.S. Patent Application No. 62/478,632 to Zimmerman and International Patent Application No. PCT/US2017/023582 to Bisiules, the disclosures of which are hereby incorporated herein by reference in their entireties.

Moreover, the series of individual phase shifters 120 according to some embodiments herein may be a part of a feed network of the base station antenna, an input of which feed network may be connected to a radio such as a remote radio head.

[0044] Each sub-component of an input RF signal may be phase shifted a fixed or variable amount by the phase shifter assembly 100. In particular, different combinations of the individual phase shifters 120 apply phase tapers to the sub-components as they are fed to individual ones of the radiating elements in the base station antenna. Such phase tapers may be used to apply an electronic down tilt to the radiation pattern formed by an array (e.g., a vertical array) of the radiating elements. As an example, a first radiating element in a linear array of the base station antenna may have a phase of Y° + 2X°, a second radiating element in the linear array may have a phase of Y° + X°, a third radiating element in the linear array may have a phase of Y°, a fourth radiating element in the linear array may have a phase of Y° - X°, and a fifth radiating element in the linear array may have a phase of Y° - 2X°.

[0045] The common linkage 140 may be a mechanical linkage (e.g., a rod or shaft) that is connected to a motor of the base station antenna. As an example, the common linkage 140 may optionally be a worm gear. The motor may drive the mechanical linkage 140 to move linearly in response to rotation of the motor. Other portions of the mechanical linkage 140 may be connected to moving parts (e.g., WPS PCBs) so that movement of the

mechanical linkage 140 results in an adjustment of a setting of the series of individual phase shifters 120 so thai the series of individual phase shifters 120 applies more or less phase shift. In some embodiments, the common linkage 140 may be any continuous piece of plastic that moves multiple wipers simultaneously. For example, one end of the common linkage 140 may be connected to a mechanical translator of an RET actuator, and the other end may be connected to each of the individual phase shifters 120. In this fashion, an external control signal received at a control input of the base station antenna may be used to change an electronic down tilt of an array of radiating elements.

[0046] FIG. IB is a front view of a main PCB 130 that may be used with a series of individual phase shifters 120 according to embodiments of present inventive concepts. The main PCB 130 includes a single RF input port 135 and a plurality of RF output ports 137. An RF signal input at the RF input port 135 is divided into a plurality of RF sub-components. The series of individual phase shifters 120 may provide different phase shifts to the respective RF sub-components, and these phase-shifted RF sub-components are output via respective ones of the RF output ports 137.

[0047] For example, among the seven RF output ports 137 illustrated in FIG. IB, the series of phase shifters 120 may apply (i) 0° of phase shift via the middle RF output port 137, (ii) positive phase shifts of various magnitudes (e.g., +1°, +2° and +3°, respectively, moving outward from the middle) via the leftmost three RF output ports 137, and (iii) negative phase shifts of the same magnitudes (e.g., -1°, -2° and -3°, respectively, moving outward from the middle) as the leftmost three RF output ports via the rightmost three RF output ports 137. Moreover, the base station antenna may adjust each of the phase-shifted values (e.g., +1°, +2°, +3°, -Γ, -2°, and -3°) by an equal amount (e.g., +x° or -x°) via the common linkage 140 that is connected to each of the phase shifters 120. Accordingly, if the adjustment is a positive value, then the adjusted phase shift values may be (+1° + x°), (+2° + x°), (+3° + x°), (- 1° + x°), (-2° + x°), and (-3° + x°). Alternatively, if the adjustment is a negative value, then the adjusted phase shift values may be (+1° - x°), (+2° - x°), (+3° - x°), (-1° - x°), (-2° - x°), and (-3° - x°).

[0048] Referring still to FIG. IB, a curved conductive trace 133 on the main PCB 130 may serve as a transmission line to the series of individual phase shifters 120. In particular, the curved conductive trace 133 may provide an RF transmission line that traverses each of the individual phase shifters 120 in the series. An RF signal may travel only one way on each curved conductive trace 133, whereas a prior art phase shifter splits its signals when they couple back to the prior art main PCB. The main PCB 130 according to embodiments herein may include, for example, a microstrip PCB where the transmission line includes the conductive trace 133 and a ground plane of the opposite side of the main PCB 130. Alternatively, the main PCB 130 may include, for example, a stripline PCB, and inner top and bottom metal surfaces of the housing 110 may provide two ground planes, respectively. [0049] Because the curved conductive trace 133 has curved bends/corners 133C instead of sharp bends/corners, it may impede high current density from resulting at linear junctions. The curved bends/corners 133C may be referred to herein as being "radiused" or "rounded." If a conductive trace instead has sharp linear junctions at the bends/corners, then high current density may be provided at the linear junctions, which can result in Passive Intermodulation (PIM) if there are imperfections in the conductive trace. Moreover, with a conventional conductive trace, if a trace width is w, then the inner radius of the bend would be at least 3 * w to maintain the characteristic impedance. The main PCB 130 according to some embodiments described herein, however, may not have space for an inner radius of 3*w. Accordingly, the main PCB 130 may use a value smaller than 3*w for the radius of the bend, and may narrow the width of the curved conductive trace 133 in the bend portion to compensate for the reduced radius of the bend.

[0050] The main PCB 130 may optionally further include a plurality of openings. For example, the main PCB 130 may include one or more arcuate openings 131 below arcuate portions of the conductive trace 133. Additionally or alternatively, the main PCB 130 may include one or more openings 139 that are configured to receive a support structure, such as the support structure 200 that will be described with respect to FIGS. 2A-2D. Moreover, in some embodiments, the main PCB 130 may include one or more openings 138 that are configured to receive a removable structure, such as the removable structure 410 that will be described with respect to FIGS. 4A-4C.

[0051] FIG. 1C is a front view of two individual phase shifters 120 according to embodiments of present inventive concepts. Each individual phase shifter 120 may comprise a small PCB that includes a curved conductive trace 123. In some embodiments, the curved conductive trace 123 may be referred to herein as an "arcuate conductive trace," due to its arc shape. The conductive traces 123 of different individual phase shifters 120 may curve in different directions, respectively, as illustrated in FIG. 1C, to conform to the pattern of the respective curved conductive traces 133 of the main PCB 130. In particular, each curved conductive trace 123 may be a U-shaped trace that includes a portion that matches the underlying arc 133 and another portion that does not. Moreover, the conductive traces 123 may have curved bends/corners 123C instead of sharp bends/corners, as discussed regarding FIG. IB with respect to the curved conductive trace 133 of the main PCB 130.

[0052] Although two individual phase shifters 120 are illustrated in FIG. 1C, the present inventive entity appreciates that the main PCB 130 of FIG. IB accommodates more than two individual phase shifters 120. Accordingly, three, four, five, six, seven, eight, or more of the individual phase shifters 120 of FIG. 1C may be used with the main PCB 130 in the phase shifter assembly 100.

[0053] Each individual phase shifter 120 in the series is rotatably mounted above (or below) the main PCB 130. In some embodiments, the design of the individual phase shifters 120 may differ depending on whether the phase shifter assembly 100 is used with a high- band or a low-band linear array of radiating elements. For example, the individual phase shifters 120 in a phase shifter assembly 100 that is coupled to a high-band array of radiating elements (e.g., radiating elements that transmit and receive signals in the 1.6-2.7 GHz frequency band or a portion thereof) may include a single arcuate conductive trace 123. In contrast, the individual phase shifters 120 in a phase shifter assembly 100 that is coupled to a low-band array of radiating elements (e.g., radiating elements that transmit and receive signals in the 694-960 MHz frequency band or a portion thereof) may include an arcuate U- shaped conductive trace, along with two arcs on the main PCB 130, to achieve twice the phase shift for a given rotation. The two arcs on the main PCB 130 may be first and second curved conductive traces that are configured to provide first and second RF transmission lines, respectively, coupled to the series of individual phase shifters 120. For example, FIG. 1G illustrates a main PCB 130 that includes first and second conductive traces 133-1, 133-2. These two conductive arcs 133-1, 133-2 may provide more phase shift from a rotation, and may thus save space. Each individual phase shifter 120 in a series on the main PCB 130 having the two conductive traces 133-1, 133-2 may have two corresponding conductive traces 123-1, 123-2.

[0054] The main PCB 130 may be a long, narrow PCB that is center fed (e.g., via the single RF input port 135). The RF input signal may be power divided to flow down two transmission line arms on the main PCB 130. The main PCB 130 may include a central output that is not variably phase shifted and that is connected to one of the two transmission line arms via a power divider. Each transmission line arm may then flow through two individual phase shifters 120 that can be adjusted to increase or decrease the phase delay. The transmission line arm may then be coupled to another power divider that sends some energy to an RF output 137 and the rest of the RF energy farther down the transmission line arm, where the design may repeat.

[0055] FIG. ID is a plan view of a housing 1 10 of the phase shifter assembly 100 according to embodiments of present inventive concepts. As illustrated in FIG. ID, portions of the individual phase shifters 120 may optionally protrude beyond an edge of the housing 1 10. The housing 110 may also optionally house two of the phase shifter assemblies 100. For example, the top row of individual phase shifters 120 in FIG. ID may be part of a first phase shifter assembly 100, and the bottom row of individual phase shifters 120 may be part of a second phase shifter assembly 100.

[0056] FIG. IE is a side view of the housing 110 of FIG. ID. This side view illustrates the optional two housing regions that house different phase shifter assemblies 100.

[0057] FIG. IF is a schematic block diagram of a base station antenna 101 that includes a phase shifter assembly 100 according to embodiments of present inventive concepts. The base station antenna 101 includes an RET actuator 190 that is connected to the common linkage 140. The base station antenna 101 also includes radiating elements 112 that are coupled to the phase shifter assembly 100.

[0058] FIG. 2A is a front view of a support structure 200 that may be used with a main PCB 130 according to embodiments of present inventive concepts, and FIG. 2B is a perspective view of the support structure 200 of FIG. 2A. As illustrated in FIGS. 2A and 2B, the support structure 200 may include curved (e.g., arcuate) portions 220. Some of these curved portions 220 may align with curved openings 131 (FIG. IB) of the main PCB 130. In some embodiments, the curved portions 220 may be referred to herein as "ribs" and/or "arcs" of the support structure 200. Accordingly, as the support structure 200 may be a plastic structure, it may be referred to herein as a "ribbed plastic support structure."

[0059] The support structure 200 may also include portions 210 and 214 that extend through, or around an edge of, the main PCB 130. For example, one or more of the portions 210 may extend through respective openings 139 (FIG. IB) of the main PCB 130 and contact the housing 110. By supporting top and bottom regions of the main PCB 130, the portions 210 may restrict vertical movement of the main PCB 130. On the other hand, by supporting side regions of the main PCB 130, the portions 214 may restrict lateral movement of the main PCB 130. As an example, one or more of the portions 214 may contact both the main PCB 130 and a side surface of the housing 110. In some embodiments, the portions 210, 214 may be referred to herein as "tabs" or "arms" of the support structure 200. Moreover, the support structure 200 may provide support for wiper arc(s) 120, which are pressed down by flexible component(s) 310 (FIG. 3B).

[0060] FIG. 2C is a front view of a support structure 200 that may be used with a main PCB 130 according to embodiments of present inventive concepts, and FIG. 2D is a perspective view of the support structure 200 of FIG. 2C. The location of bottom ones of the portions 210 of the support structure 200 of FIGS. 2C and 2D differs from the location of bottom ones of the portions 210 of the support structure 200 of FIGS. 2 A and 2B. In particular, the bottom ones of the portions 210 of the support structure 200 of FIGS. 2C and 2D are aligned with left ends of bottom curved portions 220, whereas the bottom ones of the portions 210 of the support structure 200 of FIGS. 2 A and 2B are aligned with right ends of bottom curved portions 220.

[0061] Accordingly, the support structure 200 of FIGS. 2A-2D may be a ribbed plastic support structure that is attachable to the bottom side of the main PCB 130. The support structure 200 may hold the main PCB 130 at a desired level above the floor of the housing 1 10. Ribs 220 of the support structure 200 may run directly underneath arcuate transmission line portions of the main PCB 130 that underlie the wiper arm PCBs, to ensure a constant distance between the main PCB 130 and the inside of the housing 110. Moreover, the support structure 200 may work together with flexible component(s) 310 (FIG. 3B) to ensure constant force between wiper arm PCB(s) 120 and the main PCB 130. Therefore, the main transmission line may contact the wiper arm PCBs 120, and a signal may be transmitted through a solder mask by capacitive coupling. A solder mask layer may be added as at least one layer on (a) the main PCB 130, (b) the wiper arm PCB(s) 120, or (c) both (a) and (b). Tabs 210 on the support structure 200 may extend through holes 139 in the main PCB 130 and may have a height such that they touch the ceiling of the housing 110, to keep the main PCB 130 at a desired distance from the ceiling. The support structure 200 may also include alignment tabs 214 that hold the main PCB 130 in a desired side-to-side position within the housing 110. Moreover, these tabs 214 are designed to impede longitudinal movement of the main PCB 130 that could stress solder joints. Furthermore, the support structure 200 may include a hook/tab 216 designed to impede lateral movement of the main PCB 130 that could stress solder joints.

[0062] FIG. 3 A is a rear view of a main PCB 130 that may be used with the individual serial phase shifters 120 according to embodiments of present inventive concepts. In particular, FIG. 3 A illustrates a side of the main PCB 130 that is opposite the side with the curved conductive trace 133. The support structure 200 (FIGS. 2A-2D) is on this back side of the main PCB 130. FIG. 3A also illustrates the housing 110 and the common linkage 140, as well as two instances of an RF input/output 135/137 (FIG. IB) of the main PCB 130.

[0063] FIG. 3B is an enlarged view of FIG. 3 A. FIG. 3B illustrates two bottom curved portions 220 of the support structure 200 that are aligned with respective openings 131 in the main PCB 130. In some embodiments, respective openings of these two bottom curved portions 220 may align with the openings 131 to expose back surfaces of respective ones of the phase shifter 120 PCBs, as illustrated by FIG 3B. A protruding portion (e.g., a pin 319) of a flexible component 310 (FIG. 7 A) may extend to the support structure 200 through an opening 131 of the main PCB 130. FIG. 3B also illustrates the portions 210, 214 of the support structure 200 that restrict movement of the main PCB 130. Each of the portions 214 may include a supporting feature 214S and a post 214P, as illustrated in FIG. 2D. The posts 214P may be features that restrict movement of the main PCB 130. For example, each supporting feature 214S may be referred to as a "tentacle," and a respective post 214P may be at the end of the tentacle.

[0064] Moreover, as illustrated by FIG. 3B, a plurality of flexible components 310 may be between the individual phase shifters 120 and a surface of the housing 110 that faces the curved conductive trace 133 of the main PCB 130. For example, each of the individual phase shifters 120 may have a respective flexible component 310 thereon to bias the individual phase shifters 120 against the main PCB 130. The flexible component 310 may be made of plastic and may be referred to herein as a "spring." In some embodiments, the flexible components 310 may be attachable to the common linkage 140.

[0065] For example, each flexible component 310 may be a lazy plastic spring that is mounted on top of a respective one of the individual phase shifters 120 to bias the wiper arm PCB against the main PCB 130. As a ceiling of the housing 110 may help bias the spring 310 in a desired position, the individual phase shifters 120 and the main PCB 130 may be pushed together. Moreover, solder masking may surround the RF transmission line on the main PCB 130 and extend above the metal so that the individual phase shifters 120 are spring loaded to contact the solder masking.

[0066] The plastic spring 310 for the individual phase shifters 120 may have a U- shaped tab 311 (FIG. 7 A) that connects to a pin on the common linkage 140. This tab 311 may allow the common linkage 140 to (a) be pressed close to the main PCB 130 so that the assembly can be inserted into the housing 110, but also (b) be moved farther away from the main PCB 130 when the main PCB 130 is slid laterally to allow RF inputs/outputs 135/137 to extend outside of the housing 110. This may help to simplify assembly, and reduce the size, of the phase shifter assembly 100. The U-shaped tabs 311 on the springs 310 may also help to increase/adjust an amount of longitudinal movement required to obtain a certain amount of phase shift, which may help to provide better resolution and, thus, more accurate electronic down tilt values.

[0067] FIG. 4A is a view of one side of a removable structure 410 that is attachable to a main PCB 130 and to a common linkage 140 of the phase shifter assembly 100 according to embodiments of present inventive concepts. The removable structure 410 includes holes 413 that allow a user to slide the main PCB 130 through the housing 110. For example, the holes 413 may receive a string that can pull the main PCB 130 through the phase shifter assembly 100. In some embodiments, the holes 413 may be finger holes that are accessible by a human hand to pull the main PCB 130. The removable structure 410 is attachable to the main PCB 130 via protruding portions 417 that fit in openings 138 at an end of the main PCB 130. The removable structure 410 is attachable to the common linkage 140 via protruding portions 415 that fit in openings in the common linkage 140, such as the openings 445 that will be described with respect to FIG. 4B.

[0068] FIG. 4B is a view of an opposite side of the removable structure 410 of FIG. 4A. FIG. 4B also illustrates the openings 445 in the common linkage 140 that are configured to receive the protruding portions 415. The protruding portions 415 may protrude in a direction perpendicular to a direction of movement of the main PCB 130 when pulled via the holes 413 by a user. For example, the protruding portions 415 may protrude toward a bottom surface of the common linkage 140. The protruding portions 417, on the other hand, may protrude toward a front surface of the main PCB 130 that includes the curved conductive trace 133. Moreover, FIG. 4B illustrates a curved opening 131 of the main PCB 130, as well as an RF input/output 135/137 on the main PCB 130, along with a surface of the housing 110 that faces the rear surface (FIG. 3A) of the main PCB 130.

[0069] FIG. 4C is a view of the removable structure 410 of FIG. 4B while attached to the common linkage 140 for the serial phase shifters 120. FIG. 4C also illustrates a flexible component 310 (FIG. 3B) that may be positioned between one of the individual phase shifters 120 and a surface of the housing 110 that faces the curved conductive trace 133 of the main PCB 130. Although FIG. 4 A illustrates two protruding portions 417,

embodiments herein that use three protruding portions 417 (e.g., pins), as illustrated in FIG. 4D, may help reduce stress on the main PCB 130. Moreover, FIG. 4E illustrates three openings 138 of the main PCB 130 that receive the three protruding portions 417, respectively, of the removable structure 410 of FIG. 4D.

[0070] The removable structure 410 may be a removable plastic part that facilitates assembly of the phase shifter assembly 100. This plastic piece 410 attaches to both the main PCB 130 and the common linkage 140, to impede movement by the common linkage 140 and the main PCB 130 relative to each other during insertion into the housing 110. The plastic part 410 is removed after assembly. When the main PCB 130 is slid laterally after it is received within the housing 110 to bring the RF inputs/outputs 135/137 outside of the housing 1 10, the plastic part 410 disengages from the common linkage 140 and can then be removed by hand. The removable plastic part 410 may include two holes 413 so that a user can pull the assembly into the housing 110, instead of pushing it, as the main PCB 130 can be prone to buckling. For example, the user can put a string through the housing 110, run the string through the two holes 413, and then pull on the string to pull the main PCB 130 through the housing 110.

[0071] FIG. 5 A is a perspective view of a spacer 510 that is attachable to a main PCB 130 that may be included in the phase shifter assembly 100 according to embodiments of present inventive concepts. In particular, the main PCB 130 may include openings 530 that are each configured to receive a spacer 510, as illustrated in FIG. 5B. For example, the spacer 510 may include an annular groove 513 whereby the spacer 510 attaches to the main PCB 130 when the spacer 510 is in an opening 530 of the main PCB 130. When the spacer 510 is attached to the main PCB 130, it may also extend to contact a surface of the housing 1 10.

[0072] In some embodiments, the phase shifter assembly 100 may include a plurality of the spacers 510, which may be in the form of small plastic cylinders, to space the main PCB 130 at desired distances from the floor and ceiling of the housing 110. Each spacer 510 may include the horizontal annular groove 513 that fits within a slot 530 in the main PCB 130. The slots 530 in the main PCB 130 have a large hole 531 at one end to allow the spacer 510 to be inserted. One slot 530 may face against a direction of insertion to impede the spacer 510 from being forced out of the slot 530. Another slot 530 may do the same thing for side-to-side movement.

[0073] The RF input 135 and each RF output 137 may be a contact pad on the main PCB 130. In some embodiments, for cable soldering to the main PCB 130, the base station antenna 101 may include a cable clip (made of, e.g., high dielectric-constant plastic) that extends underneath a respective one of the contact pads and receives a cable. In contrast, in conventional designs, the center conductor of a cable may be soldered to a contact pad on a main PCB, with only air underneath the main PCB contact pad. Embodiments herein that include the cable clip, however, result in the contact pad on the main PCB 130 appearing like a microstrip, which better contains RF fields, improves matching, improves insertion loss, and reduces interference with other components in the base station antenna 101. The cable clip also provides mechanical support for soldering.

[0074] FIG. 6A is a top perspective view of an embodiment of the housing 110, and FIG. 6B is a top view of the housing 110 of FIG. 6 A. The housing 110 may be a metal housing, such as an extruded aluminum housing, and may thus serve as an RF shield. As described with respect to FIGS. ID and IE, the housing 110 may include two regions that accommodate different respective series of individual phase shifters 120 so that two phase shifter assemblies 100 may share a common housing 110. As illustrated by FIG. 6A, an end of the housing 110 may include openings 613 for the respective series of the individual phase shifters 120.

[0075] FIG. 7A is a perspective view of a flexible component 310 of the phase shifter assemblies 100 according to embodiments of present inventive concepts. As discussed with respect to FIG. 3B, the flexible component 310 may bias an individual phase shifter 120 against the main PCB 130, and may include a tab 311 by which the flexible component 310 is attachable to the common linkage 140. Moreover, FIG. 7B is a side view of the flexible component 310 of FIG. 7 A attached to a main PCB 130, and FIG. 7C is a bottom perspective view of the flexible component 310 attached to the main PCB 130. As illustrated in FIGS. 7B and 7C, the flexible component 310 may include a pin 319 that extends through an arcuate opening 131 in the main PCB 130. In particular, the individual phase shifter 120 is driven by the pin 319 as a wiper on the main PCB 130, and the arcuate opening 131 provides access for the pin 319. The pin 319, extending through the arcuate opening 131 , may then engage groove(s) in the support structure 200 to improve positioning. As further illustrated in FIG. 7C, a cylindrical protruding portion 317 of the flexible component 310 may extend through a circular opening in the main PCB 130.

[0076] FIG. 8 is a perspective view of a prior art electromechanical rotary wiper arc phase shifter 800. The electromechanical rotary wiper arc phase shifter 800 may be used to implement a power divider network and a phase shifter. As shown in FIG. 8, the phase shifter 800 includes a main (stationary) PCB 810 and a rotatable wiper PCB 820 that is rotatably mounted on the main PCB 810 via a pivot pin 822. The position of the rotatable wiper PCB 820 above the main PCB 810 is controlled by the position of a mechanical linkage that may connect, for example, to post 824 on the wiper PCB 820. The other end of the mechanical linkage may be coupled to an RET actuator. For example, the mechanical linkage may be a rod, shaft, or the like that connects at one end to a piston (or other suitable mechanical translator) and connects at the other end to, for example, the wiper PCB 820 of a rotary wiper arc phase shifter 800.

[0077] The main PCB 810 includes a plurality of generally arcuate transmission line traces 812, 814. In some cases the arcuate transmission line traces 812, 814 may be disposed in a serpentine pattern to achieve a longer effective length. In FIG. 8, there are two arcuate transmission line traces 812, 814, with the first arcuate transmission line trace 812 being disposed along an outer circumference of the main PCB 810 and the second arcuate transmission line trace 814 being disposed on a shorter radius concentrically within the outer transmission line trace 812. A third transmission line trace 816 on the main PCB 810 connects an input pad 830 on the main PCB 810 to a power divider 802. A first output of the power divider 802, which carries the majority of the power of any RF signal input at input pad 830, capacitively couples to a circuit trace on the wiper PCB 820. The second output of the power divider 802 connects to an output pad 840 via a transmission line trace 818. RF signals that are coupled to this output pad 840 are not subjected to an adjustable phase shift.

[0078] The wiper PCB 820 includes another power divider (on the opposite/rear side of wiper PCB 820) that divides the RF signals coupled thereto. One output of this power divider couples to a first pad on the wiper PCB 820 that overlies the transmission line trace 812, and the other output of this power divider couples to a second pad on the wiper PCB 820 that overlies the transmission line trace 814. The first and second pads capacitively couple the respective outputs of the power divider on the wiper PCB 820 to the respective transmission line traces 812, 814 on the main PCB 810. Each end of each transmission line trace 812, 814 may be coupled to a respective output pad 840.

[0079] A cable holder 860 may be provided adjacent the input pad 830 to facilitate connecting a coaxial cable or other RF transmission line component to the input pad 830. Respective cable holders 870 may be provided adjacent each of the output pads 840 to facilitate connecting additional coaxial cables or other RF transmission line components to each output pad 840. As the wiper PCB 820 moves, an electrical path length from the input pad 830 of phase shifter 800 to each radiating element in a base station antenna changes. For example, as the wiper PCB 820 moves to the left, it shortens the electrical length of the path from the input pad 830 to the output pad 840 connected to the left side of transmission line trace 812, while the electrical length from the input pad 830 to the output pad 840 connected to the right side of transmission line trace 812 increases by a corresponding amount. These changes in path lengths result in phase shifts to the signals received at the output pads 840 connected to transmission line trace 812 relative to, for example, the output pad 840 connected to transmission line trace 818. Thus, the phase shifter 800 may receive an RF signal at input pad 830, divide the RF signal into a plurality of sub-components, apply different amounts of phase shift to each sub-component, and output the phase-shifted subcomponents on output pads 840.

[0080] In contrast with the single rotary wiper arm phase shifter in FIG. 8, however, various embodiments described herein provide a series of individual phase shifters 120 on a continuous main PCB 130. In particular, a phase shifter assembly 100 according to various embodiments herein may use a series of small rotary wiper arms to perform a phase shift. Previously, a single wiper arm was used that included a plurality of arc-shaped transmission lines, each of which had a different phase delay. A transmission line on the main PCB 130 of a phase shifter assembly 100 according to various embodiments herein, however, traverses multiple individual phase shifters 120 in series.

[0081] In some embodiments, the individual phase shifters 120 may be aligned linearly on the main PCB 130, which may make it easier to connect all of the individual phase shifters 120 to the same mechanical linkage (e.g., the common linkage 140). Using the same-size individual phase shifters 120 may make it easier, to linearly align the individual phase shifters 120. Moreover, particularly with a high-band design, the size of an aluminum extrusion housing (e.g., the housing 110) may be limited because it may have a width that is narrower than a width that supports transmission of a fundamental mode of a rectangular waveguide formed by the extruded aluminum housing. To provide sufficient phase shift, the individual phase shifters 120 may thus be nearly as wide as the underlying main PCB 130.

[0082] Providing a series of the phase shifters 120 may provide a number of advantages. These advantages include simultaneously adjusting each of the phase shifters 120 by an equal amount, by using the common linkage 140 that extends along and connects to each of the phase shifters 120. The advantages also include providing a rediiced weight, a reduced cost, and a more desirable shape relative to conventional rotary wiper phase shifters.

[0083] Present inventive concepts have been described above with reference to the accompanying drawings. Present inventive concepts are not limited to the illustrated embodiments. Rather, these embodiments are intended to fully and completely disclose present inventive concepts to those skilled in this art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity.

[0084] Spatially relative terms, such as "under," "below," "lower," "over," "upper," "top," "bottom," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the example term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0085] Herein, the terms "attached," "connected," "interconnected," "contacting," "mounted," and the like can mean either direct or indirect attachment or contact between elements, unless stated otherwise.

[0086] Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression "and/or" includes any and all combinations of one or more of the associated listed items.

[0087] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of present inventive concepts. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including" when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.