Patent Description:
Urban deployments of cellular network require antennas that are compact and offer a variety of gain profile configurations. A solution to this challenge is a cylindrical antenna having several internal array faces, or sectors, each corresponding to a given azimuthal portion of a <NUM> degree area of angular coverage. Often, depending upon the coverage area desired, it may be necessary for an antenna to have the ability to tilt its gain downwardly or upwardly. Such gain pattern adjustment is conventionally achieved with phase shifters that may be integrated into each antenna array face.

Conventional phase shifters have wiper arms that are individually engaged at the wiper arm distal end (opposite from the pivot end). This configuration has two principal disadvantages: (<NUM>) it increases the materials and number of parts associated with the phase shifter; and (<NUM>) it restricts the ability to reduce the size of the array face. The latter complication arises inasmuch as the wiper arms require a drive mechanism that extends to the outer edges of the array face along the azimuth axis. In the case of a small cell antenna, having a cylindrical configuration with three array faces, or sectors, (each oriented at <NUM> degree intervals, for example), a conventional drive mechanism interferes with the other array face PCBs. This is due to the configuration of the drive mechanism which is disposed at the outer edges of its respective array face. As such, the drive mechanism interferes with the other PCBs, i.e., where they meet.

<CIT> discloses a transmission arm for phase shifters simultaneous movement. The middle of the transmission arm is symmetrically provided with two clamping slots, the size of the clamping slots is consistent with the size of a pool rod. Two cylindrical positioning pins are arranged between the clamping slots.

<CIT> discloses a triangular prism eight port PHS base station antenna. The antenna integrates a three sector omnidirectional coverage dual polarization and directional sector dual polarized antenna into a hole and has the function of sector space dual diversity.

<CIT> discloses a phase shifter structure of a multi-polarization antenna. The phase shifter structure comprises a plurality of phase shifters, each comprising a power feeding unit, a base substrate on which an arc-shaped pattern is formed and a variable phase shifter mounted on the centre of the pattern on the substrate to be rotated about a shaft.

Accordingly, a need exists for a phase shifter having a minimal profile and part count, enabling mounting of multiple array faces within a cylindrical/sector antenna.

An aspect of the present invention involves a phase shifter arrangement for an antenna according to claim <NUM>.

According to an example that may, if applicable, provide details to further specify embodiments claimed or described in this application, the phase shifter arrangement has pair of phase shifters, each phase shifter having a first wiper arm and a second wiper arm, the first and second wiper arm each having a proximal end and a distal end and a pivot axis disposed between the proximal end and the distal end. The first and second wiper arm each have a wiper arm conductive trace disposed on its underside wherein the conductive trace is disposed between the pivot axis and the distal end, and a drive pin slot disposed between the pivot axis and the proximal end. The phase shifter arrangement has a drive shaft that has a longitudinal axis and two drive pins, wherein the drive pins are disposed on opposite sides of the drive shaft at a lateral distance from the longitudinal axis of the drive shaft and mechanically coupled to the drive shaft by a plurality of struts. Each of the drive pins mechanically couples to a corresponding first wiper arm and second wiper arm of each of the pair of phase shifters, wherein as the drive shaft translates along the longitudinal axis, each drive pin slides within the drive pin slots of the corresponding first wiper arm and second wiper arm, causing the first wiper arm and second wiper arm to rotate in unison about their corresponding pivot axes.

Another aspect of the present invention involves an antenna according to claim <NUM>.

According to an example that may, if applicable, provide details to further specify embodiments claimed or described in this application, an antenna comprises an RF signal input port, a plurality of radiators, and a phase shifter arrangement electrically coupled between the RF signal input port and the plurality of radiators. The phase shifter arrangement has a pair of phase shifters, each phase shifter having a first wiper arm and a second wiper arm. The first and second wiper arm each have a proximal end and a distal end and a pivot axis disposed between the proximal end and the distal end. The first and second wiper arm each have a wiper arm conductive trace disposed on an its underside wherein the conductive trace is disposed between the pivot axis and the distal end, and a drive pin slot disposed between the pivot axis and the proximal end. The phase shifter arrangement has a drive shaft having a longitudinal axis and two drive pins, wherein the drive pins are disposed on opposite sides of the drive shaft at a lateral distance from the longitudinal axis of the drive shaft and mechanically coupled to the drive shaft by a plurality of struts, wherein each of the drive pins mechanically couples to a corresponding first wiper arm and second wiper arm of each of the pair of phase shifters. As the drive shaft translates along the longitudinal axis, each drive pin slides within the drive pin slots of the corresponding first wiper arm and second wiper arm, causing the first wiper arm and second wiper arm to rotate in unison about their corresponding pivot axes.

Another aspect of the invention involves an antenna having a plurality of array faces according to claim <NUM>.

According to an example that may, if applicable, provide details to further specify embodiments claimed or described in this application, an antenna has a plurality of array faces, each of the plurality of array faces corresponding to a distinct azimuth angle of coverage. Each of the array faces comprises a PCB structure, a plurality of radiators disposed on the PCB structure, and a phase shifter arrangement disposed on the PCB structure. The phase shifter arrangement has a pair of phase shifters, each of the phase shifters electrically coupled between one or more RF signal inputs and the plurality of radiators. Each phase shifter has a first wiper arm and a second wiper arm, the first and second wiper arm each having a proximal end and a distal end and a pivot axis disposed between the proximal end and the distal end. The first and second wiper arm each have a wiper arm conductive trace disposed on an its underside wherein the conductive trace is disposed between the pivot axis and the distal end, and a drive pin slot disposed between the pivot axis and the proximal end. The phase shifter arrangement has a drive shaft having a longitudinal axis and two drive pins, wherein the drive pins are disposed on opposite sides of the drive shaft at a lateral distance from the longitudinal axis of the drive shaft and mechanically coupled to the drive shaft by a plurality of struts, wherein each of the drive pins mechanically couples to a corresponding first wiper arm and second wiper arm of each of the pair of phase shifters. As the drive shaft translates along the longitudinal axis, each drive pin slides within the drive pin slots of the corresponding first wiper arm and second wiper arm, causing the first wiper arm and second wiper arm to rotate in unison about their corresponding pivot axes.

So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the disclosed subject matter encompasses other embodiments as well. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views.

The invention is directed to a phase shifter assembly wherein each wiper arm has a pivot point disposed proximal the center of a wiper arm, and wherein the end opposite the distal end engages with a drive pin. Both wiper arms of the phase shifter engage with a single drive pin and thus are both driven by a single shaft that is coupled to a drive motor.

The phase shifter assembly according to the disclosure requires less material and fewer parts than a conventional phase shifter. Further, because the drive mechanism is located substantially at the center of the phase shifter (along the azimuth axis), there is more room at the outer edges of the array face PCB to enable the shrinking of the array face in the azimuth dimension, enabling a smaller small cell antenna.

<FIG> illustrates an exemplary small cell antenna <NUM>. Antenna <NUM> may have a plurality of array faces 110a, 110b, and 110c, each of which corresponding to an azimuth direction A, B, and C, whereby each array face 110a, 110b, 110c has a gain pattern that substantially covers its corresponding azimuthal portion of <NUM> degrees. Azimuth directions A, B, and C may each be orthogonal to the surface of their corresponding array faces 110a, 110b, 110c, and each may be orthogonal to the tilt (or vertical) axis z. The exemplary antenna <NUM> has three array faces, each spaced at <NUM> degrees, however, it will be understood that variations to this design, including the number and angular orientations of the array faces, are possible and within the scope of the disclosure. For example, each array face may span ninety (<NUM>) degrees or sixty (<NUM>) degrees.

Each of the array faces 110a, 110b, 110c has a printed circuit board (PCB) structure <NUM>, a plurality of radiators <NUM>, and a phase shifter assembly <NUM>. Each phase shifter assembly <NUM> provides a differential phase delay to sets of radiators <NUM> as a function of their location along the tilt axis z. Generally, the radiators <NUM> located at the center of the array face 110a/b/c along the tilt axis (phase center) are not given any phase delay, and rows of radiators <NUM> are given an increasing differential phase delay as a function of distance from phase center along the tilt axis. The general principles of phase shifters and how they function are generally known in the art.

Among the possible variations to the antenna <NUM> of the disclosure are two configurations: tri-sector, and omni-directional. For the tri-sector variation, each array face 110a, 110b, 110c operates independently. In the context used herein, the independent operation means that each array face 110a, 110b, 110c has its own RF signals coupled to its corresponding radiators <NUM>, and each phase shifter <NUM> operates independently. As such, each <NUM> degree sector operates independently, i.e., is not influenced by the RF signals in the adjacent sectors. In an omni variation, the three array faces 110a, 110b, 110c are unified in that all of the radiators <NUM> on array faces 110a, 110b, 110c are coupled to the same RF signal sources, and the phase shifters <NUM> operate in unison.

<FIG> illustrates an exemplary phase shifter assembly <NUM> according to the disclosure, as seen from the outward-facing side of an antenna array face <NUM> (use of "array face <NUM>" may simply be any or all of the array faces 110a, 110b, 110c). The phase shifter assembly <NUM> may include two pairs of wiper arms 205a and 205b, each of which is configured to rotate around their respective axis <NUM>, and are mutually, rotatably, and mechanically coupled by a drive pin <NUM>, which translates within a PCB slot <NUM>. As illustrated, the wiper arms 205a, 205b are oriented such that drive pin <NUM> is located at or near the full extent of its motion within PCB slot <NUM>. Further illustrated (in dotted lines) are wiper arms 205a, 205b with drive pin <NUM> in its center position within PCB slot <NUM>. Phase shifter assembly <NUM> further includes PCB openings <NUM> and <NUM>. PCB openings <NUM> and <NUM> which define an arcuate boundary corresponding to the sweep of the wiper arms 205a, 205b as they rotate in response to translation of the drive pin <NUM> within the PCB slots <NUM>. Each wiper arm 205a, 205b has a distal hook portion that mechanically engages with the edge of one of PCB openings <NUM>, <NUM> (described below).

The phase shifter assembly <NUM> includes a plurality of a first input/output RF signal trace <NUM>, each of which electrically couple one conductive trace to another conductive trace. For example, the wiper arm 205a, 205b may electrically couple a first input/output RF signal trace <NUM> to an second input/output RF signal trace <NUM>.

By placing the axis <NUM> proximal to the center of each of the wiper arms 205a, 205b, and by causing the wiper arms 205a, 205b to engage the drive pin <NUM> as illustrated, it is possible to drive both wiper arms 205a, 205b with a single drive mechanism (described below). In contrast, conventional wiper arms 205a, 205b have their axes at a proximal end, and are driven at their distal end.

<FIG> illustrates an exemplary phase shifter assembly <NUM> according to the disclosure, as seen from an inwardly-facing side of an antenna array face <NUM>. Wiper arms 205a, 205b are illustrated with dotted lines inasmuch as they are disposed on the other side of the PCB. Illustrated is a wiper arm drive shaft <NUM> that is mechanically coupled to drive pins <NUM> by support struts <NUM>. Translation along the tilt (or longitudinal) axis, causes the drive shaft <NUM> to uniformly engage the drive pins <NUM> in parallel. Accordingly, the drive shaft <NUM> drives the wiper arms 205a, 205b in unison within the respective PCB slots <NUM>. As a consequence, the wiper arms 205a, 205b rotate about the respective pivot points <NUM>.

<FIG> depicts is an isolated perspective view of an exemplary wiper arm 205a or 205b according to the disclosure. More specifically, and referring to <FIG> and <FIG>, each of wiper arm arms 205a, 205b has: (i) an aperture <NUM> for rotating about the pivot axis <NUM>, (ii) a hook or recurved end portion <NUM> disposed at one end, and (iii) a slot <NUM> for accepting the drive pin <NUM> which engages the wiper arms 205a, 205b as the drive shaft <NUM> translates with the PCB slot <NUM>. As mentioned hereinabove, the hook or recurved end portion <NUM> engages an edge of the PCB opening <NUM>, <NUM> to assure electrical coupling between the wiper arms 205a, 205b and: (i) a conductive trace, (ii) a first input/output RF signal trace <NUM>, and/or (iii) a second input/output RF signal input trace <NUM>. Each of the wiper arms 205a, 205b also have a step feature <NUM>, the height of which may vary from one of the wiper arms 205a, 205b to the other of the wiper arms 205a, 205b. Such features will become apparent in view of the following detailed discussion in <FIG>.

<FIG> is an edge view of an antenna array face and printed circuit board PCB <NUM> with a wiper arm pair 205a, 205b according to the disclosure. The illustrated wiper arm pair 205a, 205b may be either one of the two pairs within wiper arm assembly <NUM>. Illustrated therein are PCB openings <NUM>, <NUM>, shown as gaps in the PCB <NUM>; wiper arms 205a, 205b (i.e., rotatably coupled to the PCB <NUM> via axis <NUM>) and translatably coupled to the PCB <NUM> at an edge of the PCB openings <NUM>, <NUM> via a distal hook <NUM>. The drive pin <NUM> is coupled to both wiper arms 205a, 205b and is translatably disposed within the PCB slot <NUM>.

It will be apparent that the first wiper arm 205a and the second wiper arm 205b define variable height dimensions with respect to each of their respective step features <NUM>. Firstly, it will be apparent that for both wiper arms 205a, 205b to engage the drive pin <NUM>, they must necessarily be staggered such that one is superimposed over the other. Secondly, even though the second wiper arm 205b is the "lower" of the two wiper arms 205a, 205b that its portion with drive pin slot <NUM> is closer to PCB <NUM> that is the respective portion of wiper arm 205a, it continues to, or still, has a step feature. This is due to the fact that it remains desirable to provide distance between the lower of the two wiper arms 205a, 205b with any of the input/output RF signal traces <NUM> so as to prevent electrical signal interference with the input/output RF signal traces <NUM>.

Further illustrated in <FIG> are wiper arm conductive traces <NUM> disposed on the underside of wiper arms 205a, 205b. Wiper arm conductive traces <NUM> electrically couple with RF signal traces <NUM>, and imparts a phase delay on the RF signal traces, depending on the location of the RF signal trace (distal vs. proximal) and the angular orientation of the wiper arm 205a/b around the axis defined by pivot axis <NUM>.

In <FIG> and <FIG>, an internal perspective view of a sector antenna 110a is depicted. More specifically, an independently-driven phase shifter assembly <NUM> is provided for a single sector antenna 110a. Therein, a wiper arm (obscured by the PCB structure) is displaced and slid along the input/output RF traces by the input drive shaft <NUM>. That is, the wiper arms 205a, 205b are pivotally coupled to the input drive shaft <NUM> by the drive pins <NUM> disposed at the distal ends of a support strut <NUM>. A rotary actuator <NUM> turns a sector drive shaft <NUM> which employs a worm gear transmission to covert the rotational motion of the actuator <NUM> into linear motion along the input drive shaft <NUM>.

Translation along the tilt (or longitudinal) axis, causes the drive shaft <NUM> to uniformly engage the drive pins <NUM> in parallel and the wiper arms 205a, 205b to rotate about the respective pivot points <NUM>. The top view of the sector antenna shown in <FIG> depicts at least three independently-driven phase shifter assemblies <NUM>, each phase shifter assembly being disposed along the internal face of each sector.

In <FIG> and <FIG>, an internal perspective view of an omni-directional antenna is depicted. More specifically, a plurality of commonly-driven phase shifter assemblies 120a, 120b, 120c are driven in unison by a drive shaft/strut arrangement. Each of the phase shifter assemblies 120a, 120b, 120c is displaced by a combination of a central shaft <NUM> and a spoked support strut <NUM>, <NUM>. The central shaft <NUM> is slideably mounted to the back-side of the PCB by a shaft fitting <NUM> and translates up and down by a rotary actuator <NUM>.

Claim 1:
A phase shifter arrangement (<NUM>) for an antenna, comprising:
a pair of phase shifters, each phase shifter having a first wiper arm (205a) and a second wiper arm (205b), the first and second wiper arms each including (i) a proximal end, (ii) a distal end, (iii) a pivot axis (<NUM>) disposed between the proximal end and the distal end, and (iv) a drive pin slot (<NUM>) disposed between the pivot axis and the proximal end,
the first and second wiper arms (205a, 205b) each having a wiper arm conductive trace (<NUM>) disposed on one side thereof, and the conductive trace (<NUM>) being disposed between the pivot axis (<NUM>) and the distal end,
a drive shaft (<NUM>) having a longitudinal axis and two drive pins (<NUM>) disposed on opposite sides of the drive shaft (<NUM>) a lateral distance from the longitudinal axis of the drive shaft (<NUM>) and mechanically coupled to the drive shaft by a plurality of elongate struts (<NUM>),
wherein each drive pin (<NUM>) mechanically couples to a corresponding first wiper arm (205a) and second wiper arm (205b) of each of the pair of phase shifters, and
wherein as the drive shaft (<NUM>) translates along the longitudinal axis , each drive pin (<NUM>) slides within the drive pin slots (<NUM>) of the corresponding first and second wiper arms (205a, 205b), causing the first and second wiper arms to rotate in unison about their corresponding pivot axes (<NUM>),
wherein each first wiper arm (205a) has a first step feature (<NUM>) disposed between its pivot axis (<NUM>) and its drive pin slot (<NUM>), and each second wiper arm (205b) has a second step feature (<NUM>) disposed between its pivot axis (<NUM>) and its drive pin slot (<NUM>), wherein the second step feature is greater in height than the first step feature.