BACKGROUND

[0001] The present invention generally relates to radio communicatiQns and, more particularly, to base station antennas for cellular communications systems.

[0002] Cellular communications systems are well known in the art. In a cellular communications system, a geographic area is divided into a series of regions that are referred to as "cells,' ^* and each cell is served by a base station. The base station may include one or more base station antennas that are configured to provide two-way radio frequency ("RF") communications with mobile subscribers that are geographically positioned within the cells served by the base station. In many cases, each base station provides service to multiple "sectors," and each of a plurality of antennas will provide coverage for a respective one of the sectors. Typically, the sector antennas are mounted on a tower or other raised structure, with the radiation beam(s) that are generated by each antenna directed outwardly to serve the respective sector.

[0003] A common wireless communications network plan involves a base station serving a hexagonally shaped cell using three base station antennas. This is often referred to as a three-sector configuration. In a three-sector configuration, each base station antenna serves a 120° sector. Typically _* a 65° azimuth Half Power Beamwidth (HPBW) antenna provides coverage for a 120° sector. Three of these 120° sectors provide 360° coverage. Other sectorization schemes may also be employed.

[0004] A large number of different base station antennas are required based on the use of different frequency bands, different beamwidth requirements, local preferences, zoning requirements, operator preferences, cost requirements and various other factors. It may be expensive and time consurning to design such a large numbers of antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIGS. 1 A-l G are a ftont perspective view, a back perspective view, a front view, a side view, a back view, an end view and a cross-sectional view, respectively, of a base station antenna according to embodiments of the present invention.

[0006] FIGS.2A-2D are a front view, a side view, a back view and a cross-sectional end view, respectively, of the base station antenna of FIGS. IA-1G with the radome thereof removed.

[0007] FIG.3 is an enlarged perspective view of a portion of the antenna of FIGS. 1A-1G that illustrates one of the low band radiating elements and several of the high band radiating elements.

[0008] FIGS. 4A-4D are a top view, a side view, a bottom view and a perspective view of a dipole-to-feed board assembly of the antenna of FIGS. 1A-1G that includes two low band radiating elements.

[0009] FIG.4E is a schematic view illustrating how the feed board assembly of FIGS. 4A-4D may be assembled.

[0010] FIG, 4F is a perspective view of two different design realizations for the dipole arms included in the low band radiating elements of the feed assembly of FIGS. 4A- 4D, and FIG.4G shows a pair of alternate choked dipole arms that may be die cast as an equivalent of one of the dipoles illustrated in FIG. 4F.

[0011] FIG.4H is a circuit diagram for the printed circuit boards of two different design realizations used to form the feed stalks for the low band radiating elements included in the dipole-to-feed board assembly of FIGS. 4A-4D.

[0012] FIGS. 5A-5D are a top view, a side view, a bottom view and a perspective view of a dipole-to-feed board assembly of the antenna of FIGS. 1A-1G that includes three high band radiating elements.

[0013] FIG. 5E is a perspective View of the director support included in each of the high band radiating elements of the dipple-to-feed board assembly of FIGS. 5A-5D.

[0014] FIG.5F is a schematic view illustrating how one of the feed board assembly of FIGS.5A-SD may be assembled.

[0015] FIG. 5G is a circuit diagram for the printed circuit boards used to form the feed stalks for the high band radiating elements included in the feed board assembly of FIGS. 5A-5D, [0016] FIGS. 6A-6D are a top view, a side view, a bottom view and a perspective view of a feed board assembly of the antenna of FIGS. 1A-1G that includes two high band radiating elements.

[0017] FIG.7A is a perspective view of the radome for the antenna of FIGS. 1 A-

1G,

[0018] FIG.7B is an enlarged perspective view of a portion of the back of the radome of FIG. 7A that illustrates a mounting plate assembly thereof,

[0019] FIG.7C is a perspective view of the mounting plate of FIG.7B.

[0020] FIG.7D is an enlarged exploded perspective view illustrating how the mounting plate of FIG.7C is attached to the radome of FIG.7A.

[0021] FIG, 7E is a schematic cross-sectional view that shows the positions of a low band radiating element and two high band radiating elements when the antenna assembly is mounted within the radome of the antenna of FIGS. lA-lG.

[0022] FIG. 7F is a perspective view of a modified support bracket similar to that illustrated in FIG. 7E.

[0023] FIG. 8A is a top perspective view of a bottom end cap of the antenna of FIGS. 1A-1G.

[0024] FIGS. 8B-8C are top and bottom views, respectively, of the bottom end cap of FIG.8A after connectors have been mounted therein.

[0025] FIGS.9A-9B are top and bottom views, respectively, of a bottom end cap according to further embodiments of the present invention.

[0026] FIGS.9C-9D are top and bottom views, respectively, of a bottom end cap according to still further embodiments of the present invention.

[0027] FIGS. 10A-10B are top and bottom views of a bottom end cap according to additional embodiments of the present invention that uses a jam nut connection method to mount the connectors.

[0028] FIGS. 11 A-l IB are a front perspective view and a side view, respectively, of one of the high band phase shifters of the antenna of FIGS. 1A-1G,

[0029] FIGS. 12A-12B are a schematic front perspective view of the phase shifter of FIGS. 11A-11B with solder clips attached thereto and a perspective view of one of the solder clips, respectively. FIG. 12C is an enlarged perspective view of the solder clip of FIG. 12B attached to the main printed circuit board of the phase shifter of FIGS. llA-llB. [0030] FIG. 13A is a front view of the phase shifter of FIGS. 11Α-ΠΒ. FIGS. 13B and 13C are enlarged views of portions of the phase shifter of FIGS, 11 A-l 1 B that illustrate features for attaching individual solder clips.

[0031] FIGS. 14A-14C are a front view, a left end view, and a right end view, respectively, of four of the high band phase shifters of FIGS. 11A-11B mounted on a phase shifter mounting plate with phase cables attached to each phase shifter.

[0032] FIGS. 15A-15C are a front perspective view, a side view, and a back view, respectively, of a low band phase shifter assembly of the antenna of FIGS. 1A-1G.

[0033] FIG. X6A is a front view of the phase shifter of FIGS. 15A-15C. FIGS. 16B and 16C are enlarged views of portions of the phase shifter of FIGS. 15A-15C that illustrate features for attaching a solder clip.

[0034] FIGS. 17A-17C are a front view, a left end view, and a right end view, respectively, of two of the low band phase shifters of FIGS. 15A-15C mounted on a phase shifter mounting plate.

[0035] FIGS. 18A-18B are a schematic perspective view and top view, respectively* of a RET assembly included in the antenna of FIGS. 1 A-1G.

[0036] FIGS. 19A-19E are a perspective view, an exploded perspective view, a side view, a cross-sectional view and an end view of one of the RET units included in the RET assembly of FIGS. 18A-18B.

[0037] FIGS. 20A-20C are a top view, a side view and a perspective view of the board included on the RET unit of FIGS. 19A-19E. FIG. 20P is an enlarged view of a portion of FIG. 20C.

[0038] FIGS. 21 A-21C are a top view, a perspective view, and an end view of the board of FIGS. 20A-20D.

[0039] FIG. 22 is a schematic perspective view of a beam pointing detemrination unit that may be included in the antenna of FIGS. 1A-1G.

[0040] FIG. 23 illustrates how the radiating elements of a fourth dual-polarized array of radiating elements may be interleaved with the low band radiating elements.

DETAILED DESCRIPTION

[0041] Pursuant to embodiments of the present invention, common base station antenna platforms are provided that may be used in a wide variety of different applications and which may be modified as necessary for these applications at far lower cost. As is known to those of skill in the art, base station antennas may have widely varying requirements in terms of the frequencies at which the antennas operate, the number of frequency bands supported by the antenna, the azimuth and elevation beamwidths, the overall dimensions of the antenna and the like. As such, it may be necessary to develop a wide number of different antenna designs that have, for example, different sizes, different parts, different spacings between radiating elements, etc. Pursuant to embodiments of the present invention, "common" base station antenna platforms are provided that may serve as a base unit for a wide variety of different base station antennas. The use of such a common platform may expedite design time, provide improved manufacturability, allow for volume costing and provide various other benefits. Thus, while certain tradeoffs may be involved in using a common platform, the present inventors have developed common platforms that provide numerous other advantages that may significantly reduce costs and even provide performance improvements through the ability to further optimize design parameters since the common platform may serve as the design for a much larger group of antennas

[0042] The common base station antenna platforms according to embodiments of the invention may have components that are implemented in unit cells that are repeated throughput the antenna and which are used in many different antenna designs. The components may be designed with boundary conditions that assume an infinite array of elements so that more or fewer such unit ceil components may be used without negatively effecting antenna performance. For example, radiating elements may be implemented using a common design throughout the antenna, such as a unit cell that includes two radiating elements. Unit cell components may also be mounted with respect to other unit cell components in a common fashion. For example, a low band radiating element may be surrounded by high band radiating elements in a consistent manner.

[0043] Embodiments of the present invention will now be described in further detail with reference to the attached figures.

[0044] FIGS. 1 A-l E illustrate a base station antenna 100 according to certain embodiments of the present invention. In particular, FIG. 1 A is a front perspective view of the antenna 100, FIG. IB is a back perspective view of the antenna 100, FIG. 1C is a front view of the antenna 100, FIG. ID is a side view of the antenna 100, FIG. IE is a back view of the antenna 100, FIG. IF is an end view of the antenna 100, and FIG. 1G is a cross- sectional view taken along line 10— I G of FIG. 1 E.

[0045] As shown in FIGS. 1 A-1G, the antenna 100 is an elongated structure and has a generally rectangular shape. In an example embodiment, the width and depth of the antenna 100 may be fixed, while the length of the antenna 100 may be variable. In one example embodiment,: the antenna 100 has a width of 350 mm, a depth of 208 mm and a variable length. The antenna 100 includes a radome 110 and a top end cap 112. In some embodiments, the radome 110 and the top end cap 112 may comprise a single integral unit, which may be helpful for waterproofing the antenna 100. A pair of mounting brackets 114 are provided on the rear side of the radome 110 which may be used to mount the antenna 100 onto an antenna mount (not shown) on, for example, an antenna tower. The antenna 100 also includes a bottom end cap 120 which includes a plurality of connectors 140 mounted therein. The bottom end cap 120 and connectors 140 will be discussed in greater detail with reference to FIGS. 8A-8C. The antenna 100 is typically mounted in a vertical configuration (i.e., the long side of the antenna 100 extend along a vertical axis with respect to the earth).

[0046] FIGS.2A-2D are a front view, a side view, a back view and an end view, respectively, of the base station antenna 100 of FIGS. 1 A-1D with the radome 110 thereof removed.

[0047] As shown in FIGS. 2A-2D, the antenna 100 includes an antenna assembly 200 that is siidably inserted into the radome 110 through the bottom opening 113 (see FIG. 7A) thereof. The antenna assembly 200 includes a ground plane structure 210 that has sidewalls 212, which here include RF choke sections, and a reflector surface 214. Various mechanical and electronic components of the antenna are mounted to the ground plane structure 210, as will be described in further detail below. These electronic and mechanical components include, among other things, phase shifters 500, 600, remote electronic tilt ("RET') units 720, mechanical linkages, diplexers, and the like. The ground plane structure 210 may comprise the back portion of the antenna assembly 200, and may not include a back wall to expose the electrical and mechanical components. The reflector surface 214 of the ground plane structure 210 may comprise or include a metallic surface that serves as a reflector and ground plane for the radiating elements of the antenna 100. Herein the reflector surface 214 may also be referred to as the reflector 214.

[0048] A plurality of radiating elements 300, 400 are mounted on tile reflector surface 214 of the ground plane structure 210. The radiating elements include low band radiating elements 300 and high band radiating elements 400. The low band radiating elements 300 are mounted along a first vertical axis and may extend along the full length of the antenna 100 in some embodiments. The column of low band radiating elements 300 form an array 220 of low band radiating elements. The high band radiating elements 400 may be divided into two groups that are mounted along respective second and third vertical axes with the first vertical axis (and the low band radiating elements 300) extending therebetween. The high band radiating elements 400 may not extend the full length of the antenna 100 in some embodiments as shown. In some instances, multiple high band arrays can be arranged in the second and/or third vertical axes. The first column of high band radiating elements 400 form a first array 230 of high band radiating elements, and the second column of high band radiating elements 400 form a second array 240 of high band radiating elements. The low band radiating elements 300 may be configured to transmit and receive signals in a first frequency band. In some embodiments, the first frequency band may be a wide band and may comprise the 694-960 MHz frequency range. The high band radiating elements 400 may be configured to transmit and receive signals in a second frequency band. In some embodiments, the second frequency band may also be a wide band and may comprise the 1.695-2.690 GHz frequency range, As will be discussed in further detail herein, the low band and high band radiating elements may be implemented as modular groups of radiating elements to simplify antenna design.

[0049] FIG.3 is an enlarged perspective view of a portion of the antenna 100 with the radome 110 removed that illustrates one of the low band radiating elements 300 and several of the high band radiating elements 400 in greater detail. As shown in FIGS.2D and 3, the low band radiating elements 300 are taller (above the reflector 214) than the high band radiating elements 400 and extend over the high band radiating elements 400. FIG.3 also illustrates a plastic radome support 202 that abuts the inner surface of the radome 110 when the antenna assembly 200 is installed within the radome 110.

[0050] Note that the antenna 100 and antenna assembly 200 are described using terms that assume that the antenna 100 is mounted for use on a tower with the vertical axis of the antenna 100 extending al ong a vertical axis and the front surface of the antenna 100 mounted opposite the tower pointing toward the coverage area for the antenna 100. In contrast, the individual components of the antenna 100 such as the radiating elements 300, 400 and various other components may be described using terms that assume that the antenna assembly 200 is mounted on a horizontal surface with the radiating elements 300, 400 extending upwardly. Thus, while, for example, the dipole arms 330 of the low band radiating elements 300 will be described as being the top portion of the radiating element 300 and as being above the reflector 214, it will be appreciated that when the antenna 100 is mounted for use the dipole arms 330 will point forwardly from the ground plane structure 210 as opposed to upwardly.

[0051] FIGS.4 A-4D are a top view, a side view, a bottom view and a perspective view of a dipole-to _^ feed board assembly 250 of the antenna 100 of FIGS. 1A-1D that includes two low band radiating elements 300. Five of the feed board assemblies 250 are included in the antenna 100, as can be seen in FIGS.2A-2B. FIG.4E is a schematic view illustrating how the feed board assembly 250 of FIGS.4A-4D may be assembled. FIG. 4F is a perspective view of two different design realizations for the dipole arms included in the low band radiating elements of the feed assembly 250, and FIG.4G shows an alternate dipole arm design that may be die cast as an equivalent of one of the dipole arms illustrated in FIG. 4F. FIG. 4H is a circuit diagram for the printed circuit boards of two different design realizations used to form the feed stalks for the low band radiating elements included in the dipole-to-feed board assembly 250 of FIGS, 4A-4D.

[0052] As shown in FIGS. 4A-4E, the dipole-to-feed board assembly 250 includes a printed circuit board 252 that has first and second low band radiating elements 300-1 _» 300-2 extending upwardly from either end thereof. The printed circuit board 252 includes RF transmission line feeds 254 that provide RF signals to, and receive RF signals from, the respective low band radiating elements 300-1, 300-2. Each low band radiating element 300 includes a pair of feed stalks 310, a dipole support 320, four dipoles 330, and a director 340.

[0053] The feed stalks 310 may each comprise a printed circuit board 312 that has RF transmission lines formed thereon. In some embodiments, each printed circuit board 312 may be a single layer printed circuit board. As shown in FIG.4E, a first of the feed stalks 310-1 includes a lower slit 314-1. The second of the feed stalks 310-2 includes an upper slit 314-2. The slits 314 allow the feed stalks 310 to be assembled together to form a vertically extending column that has generally x-shaped horizontal cross-sections. Lower portions of each printed circuit board 312 include plated projections 316. These plated projections 316 of the printed circuit boards 312 are inserted through slits 256 in the printed circuit board 252. The plated projections 316 of printed circuit board 312 may be soldered to plated portions on printed circuit board 252 that are adjacent the slits 256 to electrically connect the printed circuit boards 312 to the printed circuit board 252. The plated projections 316 may also facilitate using automated selective wave soldering techniques to solder the printed circuit boards 312 to the printed circuit board 252. Such automated selective wave soldering techniques may decrease manufacturing costs and provide for more consistent and/or improved solder joints.

[0054] Each printed circuit board 312 includes an arm 318 that has a plated portion 319 at the base thereof. FIG. 4E illustrates one example implementation of the arm 318. The configuration of the arm 318 may be based on the design of the dipoles 330 so that the dipoles 330 may be mounted on the respective arms 318. [0055] FIG.4H is a circuit diagram for the printed circuit boards 312 for two different design realizations. Each printed circuit board 312 may consist of a single substrate with conductive traces on both sides, or may consist of a bonded set of substrates to form a bonded printed circuit board with conductive traces on both sides and in between the bonded substrates. As shown in FIG. 4H, each printed circuit board includes transmission lines 315 that cany RF signals between the printed circuit board 252 and the dipoles 330. Inductors in the form of meandering transmission line segments 317 are also provided at each arm 318 that, in conjunction with a coaxial capacitor that is implemented as part of each dipole 330, form a series inductor-capacitor circuit that impedance match the transmission lines 315 to the dipoles 330. The designs for the printed circuit boards illustrated in FIG.4H also each include a set of open circuit stubs depicted on the outer edges of the printed circuit boards which connect to the transmission lines 315 on one end and which are open-circuited on the other end. These open circuit stubs may improve high band performance by reducing some coupling caused by the low band feed stalks 310.

[0056] Referring again to FIGS.4A-4E, the dipole support 320 may comprise, for example, a plastic support that is mounted to extend upwardly from the printed circuit board 252. In the depicted embodiment, each dipole support 320 comprises a base 322 that surrounds the lower portions of a mated pair of printed circuit boards 312. Arms 324 extend upwardly and outwardly from the base 322. Each arm 324 terminates in an upwardly extending dipole clip 326 that is configured to receive and hold a central portion of a respective one of the dipoles 330. In the depicted embodiment, each dipole clip 326 comprises a pair of cantilevered fingers 328 that together define a semi-circular inner radius. Horizontal supports 329 extend between adjacent arms 324 to provide additional structural rigidity. The dipole supports 320 help hold the dipoles 330 in their proper positions and reduce the forces applied to the joint where the dipoles 330 connect to their respective arms 318 on the printed circuit boards 312. The dipole supports 320 may also reduce the forces applied to the solder joints where feed stalks 310 connect to the feed board printed circuit board 252.

[0057] Each dipole 330 may be, for example, comprised of dipole arms that are between a 3/8 to ½ of a wavelength in length, where the "wavelength" refers to the wavelength in approximately the middle of the frequency range of the low band. A total of four dipole arms 330-1 through 330-4 are provided, and the dipoles 330 are arranged in the shape of a cross. Dipole arms 330-1 and 330-2 together form a first radiating element 332-1. In the depicted embodiment, the first radiating element 332-1 is designed to transmit signals having a +45 degree polarization. Dipole arms 330-3 and 330-4 together form a second radiating element 332-2. In the depicted embodiment, the second radiating element 332-2 is designed to transmit signals having a -45 degree polarization. The dipole arms 330 may be mounted approximately a quarter wavelength above the reflector 214 by the feed stalks 310. The reflector 214 may be immediately beneath the feed board printed circuit hoard 252.

[0058] Each dipole arm 330 may comprise an elongated center conductor 334 that has a series of coaxial chokes 336 mounted thereon. Each coaxial choke 336 comprises a hollow metal tube mat has an open end and a closed end that is grounded to the center conductor 334. The coaxial chokes 336 are used to create a quarter wavelength well in the high frequency band that may makes the low band radiating element 300 substantially invisible to transmission in the high frequency band.

[0059] In on embodiment, each dipole arm 330 may be die cast and may be configured for press fit assembly with the center conductor 334 in each piece press fit into a hole at the end of the coaxial choke 336 on the adjacent piece. This eliminates solder joints in the dipoles 330, thereby simplifying assembly and improving performance.

[0060] FIG.4F illustrates two different designs for the dipoles 330. The dipole 330A may comprise a machined dipole. to this embodiment, the entire inner conductor may be machined to two different diameters, namely short, larger diameter sections where the creased lines are made in the choke tube region and longer, smaller diameter sections that run between the larger diameter sections to provide a dipole arm that has the shape of a series of dumbbells. A trimmed tube is placed oyer each larger diameter section to create the hollow choke and this tube may be roll-formed to the larger diameter section to provide a tight fit. Dipole 330B comprises a die cast dipole which may he press fit together without the need for any solder joints. FIG. 4G shows an alternative dipole arm design 338 that may be used as an alternative type of choked dipole arm.

[0061] A director 340 may be mounted on top of each feed stalk 310. The director 340 may comprise a conductive material and, in some embodiments, may comprise sheet metal. Each director 340 may be clipped onto its respective feed stalk 310 in some embodiments. The directors 340 may be used to improve the impedance match of the dipole antenna.

[0062] Referring now to FIG. 4E, the steps used to assemble the feed board assembly 250 are shown schematically. As shown in FIG. 4E, the printed circuit boards 312 may be paired to form the feed stalks 310-1, 310-2, and these feed stalks 310 may be inserted into the slits 256 in the printed circuit board 252 and soldered in place using, for example, an automated soldering solution such as selective wave soldering. Then, the dipoie supports 320 may be mounted on the printed circuit board to surround the respective feed stalks 310. The dipoie supports 320 may be secured in place by, for example, rivets that extend through holes in the printed circuit board 252 and into the underlying reflector 214. Finally, the dipoie arms 330 may be attached to the respective arms 318 of printed circuit board 312.

[0063] FIGS. 5A-5D are a top view, a side view, a bottom view and a perspective view of a dipole-to-feed board assembly 260 of the antenna 100 of FIGS. 1A-1G that includes three high band radiating elements. FIG. 5E is a perspective view of a director support included in each of the high band radiating elements of the dipole-to-feed board assembly 260. FIG. 5F is a schematic view illustrating how the dipole-to-feed board assembly 260 may be assembled. FIG. SG is a circuit diagram for the printed circuit boards used to form the feed stalks for the high band radiating elements included in the feed board assembly 260.

[0064] As shown in FIGS. 5A-5D, the dipole-to-feed board assembly 260 includes a printed circuit board 262 that has three high band radiating elements 400-1, 400-2, 400-3 extending upwardly therefrom. The printed circuit board 262 includes RF transmission line feeds 264 that provide RF signals to, and receive RF signals from, the respective high band radiating elements 400-1 through 400-3. Bach high band radiating element 400 includes a pair of feed stalks 410-1, 410-2, a dipoie radiating element 420, a director support 430, and a director 440.

[0065] The feed stalks 410 may each comprise a printed circuit board 412 that has RF transmission line feeds 264 formed thereon. Each of the feed stalks 410-1 includes a lower slit and each of the feed stalks 410-2 includes an upper slit so that the feed stalks 410 may be assembled together to form a vertically extending column that has generally x-shaped horizontal cross-sections. Lower portions of each printed circuit board 412 include plated projections 416. These plated projections 416 are inserted through slits 266 in the printed circuit board 262. The plated projections 416 may be soldered to plated portions on printed circuit board 262 that are adjacent the slits 266 to electrically connect the printed circuit boards 412 to the printed circuit board 252. The plated projections 416 may also facilitate using automated selective wave soldering techniques to solder the printed circuit boards 412 to the printed circuit board 262. Such automated selective wave soldering techniques may decrease manufacturing costs and provide for more consistent and/or improved solder joints.

[0066] FIG.5G is a circuit diagram for the printed circuit boards 412. Each printed circuit board 412 may consist of a single substrate with conductive traces on both sides and containing some plated through holes. As shown in FI G. 5G, each printed circuit board 412 includes transmission lines 415 that carry RF signals between the printed circuit board 262 and the dipole radiating elements 420.

[000] Each dipoie radiating element 420 comprises a printed circuit board having four plated sections 422 formed thereon that form the four dipole arms of a cross-dipole radiator. The four plated sections 422 are arranged in a general cruciform shape. Plated sections 422-1 and 422-2 together form a. first radiating element 424-1, In the depicted embodiment; the first radiating element 424-1 is designed to transmit signals having a +45 degree polarization. Plated sections 422-3 and 422-4 together form a second radiating element 424-2. In the depicted embodiment, the second radiating element 424-2 is designed to transmit signals having a -45 degree polarization. The radiating elements 424 may be mounted approximately a quarter wavelength above the reflector 214 by the feed stalks 410.

[0068] Referring to FIG. 5E, each director support 430 may comprise, for example, a plastic support that is mounted to extend upwardly from a respective one of the dipole radiating element printed circuit boards. In the depicted embodiment, each director support 430 comprises a base 432 that clips onto mating features on the printed circuit board of its associated dipole radiating element 420. Arms 434 extend upwardly and outwardly from the base 432 and join together to form an upper shelf 436. A clip 438 extends upwardly from the upper shelf 436.

[0069] The directors 440 are mounted on the respective director supports 430. Each director 440 comprises a flat metal plate. In the depicted embodiment, the directors 440 are cut into a "double arrow" shape. This shape may help make the radome 110 transparent to the high band radiating elements 400 and may also improve the dipole impedance match. Each director 440 includes a central aperture 442. The clip 438 of its respective director support 430 is inserted through this aperture 442 to mount the director 440 on its respective director support 430.

[0070] Referring now to FIG. 5F, the steps used to assemble the feed board assembly 260 are shown schematically. As shown in FIG. 5F, the printed circuit boards 412 may be paired to form the feed stalks 410-1, 410-2. The dipole radiating elements 420 may then be soldered to the feed stalks 410 using wave soldering. Then, the plated projections 416 on the feed stalks 410 (with the printed circuit board of the dipole radiating elements 420 soldered to the feed stalks 410) may be inserted into the slits 266 in the printed circuit board 262 and spidered in place using selective wave soldering. While not shown in FIG. 5F, the director supports 430 may then be mounted on the dipoie radiating elements 420, and the directors 440 may be mounted on the respective director supports 430.

[0071] FIGS.6A-6D are a top view, a side view, a bottom view and a perspective view of a feed board assembly 270 of the antenna 100 of FIGS. 1A-1G that includes two high band radiating elements 400.

[0072] As shown in FIGS. 6A-6D, the dipoie-to-feed board assembly 270 includes a printed circuit board 272 that has two low band radiating elements 400-1, 400-2 extending upwardly therefrom. The printed circuit board 272 includes RF transmission line feeds 274 that provide RF signals to, and receive RF signals from, the respective high band radiating elements 400-1, 400-2. As the dipole-to-feed board assembly 270 is similar to the dipole-to- feed board assembly 260 except mat it has a smaller printed circuit board 272 and only two, instead of three, high band radiating elements 400, further description of the feed board assembly 270 will be omitted.

[0073] As noted above, the low band and high band radiating elements 300, 400 are arranged as one low band array 220 and two hi gh band arrays 230, 240 of radiating elements. Each array 220, 230, 240 may be used to form a separate antenna beam. In an example embodiment, the radiating elements 300 of the low band array 220 may be vertically spaced apart from each other at 265 mm intervals, and the radiating elements 400 of each high band array 230, 240 may be vertically spaced apart from each other at 1Q6 mm intervals. Each radiating element 400 in the first high band array 230 may be horizontally aligned with a respective radiating element 400 in the second high band array 240. The radiating elements 400 in the first high band array 230 may be spaced apart by 160 mm from their respective horizontally aligned radiating elements 400 in the second high band array 240.

[0074] FIG.7A is a perspective view of the radome 110. FIG. 7B is an enlarged perspective view of a portion of the back of the radome 110 that illustrates a mounting plate assembly 114 thereof. FIG.7C is a perspective view of the mounting plate 114. FIG. 7D is an enlarged exploded perspective view illustrating how the mounting plate 114 of FIG. 7C is attached to the radome 110. FIG. 7E is a schematic cross-sectional view that shows the positions of a low band radiating element 300 and two high band radiating elements 400 when the antenna assembly 200 is mounted within the radome 110. FIG.7F is a perspective view of a modified support bracket similar to that illustrated in FIG _* 7E.

[0075] As shown in FIG.7A, the radome 110 may comprise a hollow, generally rectangular tube with an open bottom 113. The radome 110 may be of conventional design. The radome 110 may be made of fiberglass in some embodiments. The radome 110 may be formed by a pultrusion process or an extrusion process in some embodiments, A top end cap 112 may be formed integrally with the radome 110 or may be formed separately and permanently attached to the radome 110 in some embodiments.

[0076] As noted above, a pair of mounting plates 114 are mounted on the back side of the radome 110. As shown in FIGS. 7B-7D, each mounting plate 114 may comprise a base plate 115 that has two flanges 116 extending therefrom. A lip 117 may extend around the periphery of the base plate 115. Four mounting holes 118 are provided in the base plate. A hole Π8 is also provided near the distal end of each flange 116.

[0077] As shown in FIG.7E, the low band radiating elements 500 and the high band radiating elements are mounted on the ground plane structure 210. The reflector surface 214 of the ground plane structure 210 may comprise a sheet of metal that, as noted above, serves as a reflector and as a ground plane for the radiating elements 300, 400. The sidewalls 212 of the housing 210 may be formed by bending the sheet metal used to form the reflector surface 214 downwardly on each side. In the depicted embodiment, the sheet metal on each side is bent multiple times to form U-shaped sidewalls 212 which therein form respective JRF chokes. A pair of spaced-apart brackets 216 are provided that extend between the sidewalls 212. FIG. 7F is a perspective view of the bracket 216. The brackets 216 provide mechanical rigidity to the ground plane structure 210 and also provide locations for mounting the above- described mounting brackets 114 through the radome 110. As is also shown in FIG. 7E, the front surface of the radome 110 may have a slight protrusion to accommodate the height of the low band radiating elements 300.

[0078] FIG, 8A is a top perspective view of a bottom end cap 120 of the antenna 100. FIGS, 8B-8C are top and bottom views of the bottom end cap 120 after connectors have been mounted therein.

[0079] As shown in FIG. 8 A, the bottom end cap 120 includes a base plate 122, which may be substantially planar. An outer wall 124 protrudes upwardly around the periphery of the base plate 122 and extends around the perimeter of the base plate 122. An inner wall 126 also protrudes upwardly from the base plate 122. The inner wall 126 is located closer to the center of the base plate 122 than is the outer wall 124, and the inner wall 126 may be spaced apart from the outer wall 124 by a substantially constant distance to define a channel 128 that is between the inner wall 126 and the outer wall 124. The inner wall 126 may extend higher than the outer wall 124. A plurality of slots 130 may be formed in the bottom of the channel 128. [0080] The base plate 122 may further include a plurality of vertically extending columns 132, each of which includes a central aperture 133. Screws (not shown) may be inserted through the respective central apertures 133 and threaded into mating apertures on the antenna assembly 200 (e.g., the screws may be threaded into mating apertures on connector flanges of input connectors that are part of the antenna assembly 200) to attach the bottom end cap 120 to the remainder of the antenna 100. The bottom edge of the radome 110 is received within the channel 128. The higher inner wall 126 helps reduce or prevent water/moisture from entering into the interior of the radome 110. The slots 130 also facilitate allowing any water that enters the channel 128 (by seeping into any gap between the outer surface of the radome 110 and the inner surface of the outer wall 124) to drain through the base plate 122. Gussets 135 may be provided to support the inner wall 126.

[0081] The bottom end cap 120 may be formed of, for example* plastic or fiberglass. In some embodiments, the bottom end cap 120 may comprise a molded structure.

[0082] The bottom end cap 120 further includes a plurality of connector mounts 134. Each connector mount 134 may comprise a reinforced portion of the base plate 122 that includes a weakened central region 136 that may be readily punched out to form an aperture for a respective connector. The connector mounts 134 may also include additional small weakened regions 136 that are provided about the periphery that may be punched out or otherwise removed to create screw holes that may be used when mounting connectors in the respective connector mounts 134. By not pre-forming the apertures for the connectors the bottom end cap 120 may be custom designed to have the correct number of connector mounts 134 for the antenna 100 on which the bottom end cap 120 is to he installed. In the example of FIG. 8A, only some of the connector mounts 134 have had the weakened region 136 removed.

[0083] Referring to FIGS.8B and 8C, the bottom end cap 120 of FIG, 8A is shown after connectors 140 have been installed in each connector mount 134. In the embodiment of FIGS. 8B-8C, all of the connector mounts 134 are used to mount connectors 140. The connectors 140 are arranged about the bottom and sides of the base plate 122 (which corresponds to the back and sides of the antenna 100). This arrangement may facilitate reducing PIM distortion as the connectors 140 are located farther away from the radiating elements 300, 400 which may be located in close proximity to the bottom end cap 120.

Connector mounts 135 are also provided for a pair of AJSG connectors 141 mat are used to carry control signals that control the positions of the wiper boards on the phase shifters that are described herein. [0084] FIGS.9AB-9B are top and bottom views, respectively, of a bottom end cap 120' according to further embodiments of the present invention. As shown in FIGS.9A-9B, the bottom end cap 120' is very similar to the bottom end cap 120 of FIGS;. 8A-8C, except that the bottom end cap 120' includes two additional connector mounts 134 for a total of fourteen connector mounts 134. FIGS.9C-9D are top and bottom views, respectively, of a bottom plate 120" according to still further embodiments of the present invention. The bottom plate 120" is identical to the bottom plate 120' except that the bottom plate 120" has connector mounts 134" that are sized for 7/16 inch connectors while the bottom plate 120' has connector mounts 134' that are sized for 4.3-10 connectors.

[0085] FIGS, 10A-10B are schematic top and bottom views, respectively, of a bottom end cap 150 according to additional embodiments of the present invention that is used in conjunction with jam nut connections.

[0086] As can be seen from FIGS, 1 O A and 10B, the bottom end cap 150 is similar to the bottom end caps 120, 120% 120" discussed above, although the bottom end cap 150 is also configured to accommodate a different number of connectors 140 (while the bottom end cap 150 is not showfc as including any AISO connectors 141, typically such AISG connectors 141 would be included in an actual design). Additionally, the bottom end cap 150 is configured for use with jam nut connectors 160. The use of jam nut connections may reduce or eliminate the need to twist the input cables that connect the connectors 140 to phase shifters that are included within the antenna 100 (see discussion below). This is

advantageous, because twisting the input cables may apply a force to the solder joints that connect the input cables to the phase shifter printed circuit boards, and this force may degrade the solder joint, which may lead to reduced performance (e.g., increased PIM distortion).

[0087] The antenna 100 further includes a plurality of low band phase shifters 500. As known to those of skill in the art, base station antennas may include phase shifters that may be controlled electronically from a remote location that are used to electronically do wntilt the beam patterns formed by the arrays of radiating elements, in a manner known to those of skill in the art.

[0088] FIGS. 11 A-llB are a front perspective view and a side view, respectively, of a high band phase shifter 500 that is included in the antenna 100, As shown in FIG. 11 A, the phase shifter 500 includes a main printed circuit board 510 and a wiper printed circuit board 530 that is pivotally mounted on the main printed circuit board 510. The phase shifter 500 may be of conventional design. The phase shifter 500 also includes one input port 520 and seven output ports 521-527, each of which are mounted on the main printed circuit board S10 and which may be used to transfer RF signals to/from the main printed circuit board 510. Cables may be soldered to each of the ports 520-527 to electrically connect each cable to the phase shifter 500. The main printed circuit board 510 also includes RF transmission lines 511-515. The lengths of the cables attached to the phase shifter outputs are appropriately determined to accommodate the phase needed in each path for the given design. It will also be appreciated that phase shifters haying more or fewer outputs may be used in other embodiments.

[0089] The wiper printed circuit board 530 is mounted on the top surface of the main printed circuit board 510 and configured to move in an arc rotation above the main printed circuit board 510. An RP signal that is input to the main printed circuit board 510 at input port 520 is carried by RF transmission line 511 to a power divider region which divides the incoming RF signal, lite divided signal is passed to RF transmission line 512 to the fourth output port 524 and to the wiper printed circuit board 530. RF transmission lines (not shown) on the wiper printed circuit board 530 carry the RF signal on the wiper printed circuit board 530 to positions directly above RF transmission lines 513-515 on the main printed circuit board 510 so that the input RF signal may capacitively couple to RF transmission lines 513- 515. The respecti ve ends of transmission lines 513-515 couple to the remaining six output ports 521-523 and 525-527. Thus, an RF signal input at input port 520 may be split (either equally or unequally depending upon the design of the phase shifter 500) and carried to the seven output ports 521-527.

[0090] As discussed above, the wiper printed circuit board 530 is pivotally mounted on me main printed circuit board 510 so that the wiper printed circuit board 530 may move in an arc on top of the main printed circuit board 510. The RF transmission lines 513-515 are also arc shaped. As such, if the wiper printed circuit board 530 moves, for example, to the left in the view of FIG. 11 A, then the lengths of the RF transmission paths between input port 520 and output ports 521-523 are shortened (and shortened by different amounts since the arc-shaped RF transmission lines 513-515 have different radii), while the lengths of the RF transmission path between input port 520 and output ports 525-527 are increased. As increasing or decreasing the length of the RF transmission path results in a phase shift, it can be seen that by moving the wiper printed circuit board 530 to the left, the phase of the RF signal received at six of the seven output ports 521-527 will be changed, with the phase at three of the output ports being changed by different amounts in one direction (e,g., increased) and the phase at three other of the output ports being changed in the other direction by different amounts. Accordingly, simply by moving the wiper printed circuit board 530, different phase shifts may be applied to the RF signal fed to each of seven radiating elements, or sub-array groups of radiating elements.

[0091] Referring to FIGS. 2A-2B, it can be seen that each high band array 230, 240 includes a total of sixteen high band radiating elements 400 that are arranged in seven groups of two or three radiating elements 400 each. Each of the seven groups may comprise one of the feed board assemblies 260 or one of the feed board assemblies 270 that are described above. Each feed board assembly 260, 270 that is included in, for example, high band array 230, may be connected by respective phase cables to the seven output ports 521-527 on the phase shifter 500. l¾e phase shifter 500 may thus apply phase shifts to the signals applied to (or received from) the seven groups of high band radiating elements 400 in order to apply an electronic downtilt to one of the high band arrays 230, 240,

[0092] FIGS. 12A-12B are a schematic front perspective view of the phase shifter 500 with solder clips 550, 560 attached thereto and a perspective view of the solder clip 550, respectively. FIG. 12C is an enlarged perspective view of the solder clip 550 attached to the main printed circuit board 510 of the phase shifter 500. FIG. 13A is a front view of the phase shifter 500, and FIGS. 13B and 13C are enlarged views of portions of the main printed circuit board 510 that are designed to facilitate attachment of the solder clip 550 thereto.

[0093] Referring to FIGS. 12A-13C, first and second solder clips 550, 560 are attached to either side of the main printed circuit board 510. Each solder clip 550, 560 may comprise a unitary piece of metal that has four U-shaped features 552 that are configured to hold a respective coaxial cable that is to be soldered to the main printed circuit board 510. FIG. 12B shows the solder clip 550 that is configured to receive and hold the RF input cable and three of the output cables. As is apparent from FIG. 12B, the input cable may have a larger diameter than the output cables, and hence one of the U-shaped features 552 on solder clip 550 is larger than the remaining three U-shaped features 552. On solder clip 560, each of the U-shaped features 562 may be the same size, as the solder clip 560 is designed to receive and hold four output coaxial cables.

[0094] The use of a single solder clip 55Q, 560 on each side of the main printed circuit board 510 may reduce the number of parts required, simplify assembly, and may better accommodate the use of selective wave soldering techniques. The solder clip 550 further includes an integrated grounding feature 554 that provides a DC ground path for the outer conductors of the input cables that attach to ports 520-527. The grounding feature 554 may be electrically connected to, for example, the mounting bracket 114 to ground the outer conductors of the cables to the mounting structure for antenna 100 (e.g., to an antenna tower). As shown in FIGS. 12A-13C, the solder clips 550 _» 560 may be mechanically attached to the main printed circuit board 510 by including attachments fingers 570 on side edges of the main printed circuit board 510 that are inserted within slots 556 on the solder clips 550, 560.

[0095] FIGS. 14A-14C are a front view, a left end view, and a right end view, respectively, of fpur of the high band phase shifters 500 of FIGS. 11A-11B mounted on a phase shifter mounting plate 580. The phase shifter plate $80 may include features that hold the input cable and the output phase cables for each phase shifter 500 in place which may facilitate soldering the cables to the respective phase shifter printed circuit boards 510. In some embodiments, the phase shifter plates 580 may be die cast. The phase shifter plate 580 may extend substantially all the way across the back of the antenna 100.

[0096] FIGS. 15A-15C are a front perspective view, a side view, and a back view, respectively, of a low band phase shifter 600 that is included in antenna 100. As shown in FIG. 15A, the phase shifter 600 includes a main printed circuit board 610 and a wiper printed circuit board 630 that is pivotal iy mounted on the main printed circuit board 610. The phase shifter 600 further includes one input port 620 and five output ports 621-625, each of which are mounted on the main printed circuit board 610 and which may be used to transfer RF signals to/from the main printed circuit board 610. The main printed circuit board 610 also includes RF transmission lines 611-614.

[0097] The wiper printed circuit board 630 is mounted on the top surface of the main printed circuit board 610 and configured to move in an arc above the main printed circuit board 610. An RF signal that is input to the main printed circuit board 610 at input port 620 is carried by RF transmission line 611 to a power divider region which divides the incoming RF signal. The divided RF signal is passed to RF transmission line 612 to the third output port 623 and to the wiper printed circuit board 630. RF transmission lines (not shown) on the wiper printed circuit board 630 carry the RF signal on the wiper printed circuit board 630 to positions directly above RF transmission lines 613-614 on the main printed circuit board 610 so that the input RF signal may capacitively couple to RF transmission lines 613-614. The respecti ve ends of transmission lines 613-614 couple to the remaining four output ports 621- 622 and 624-625. Thus, an RF signal input at input port 620 may be split (either equally or unequally depending upon the design of the phase shifter 600) and carried to the five output ports 621-625.

[0098] As discussed above, the wiper printed circuit board 630 is pivotally mounted on the main printed circuit board 610 so that the wiper printed circuit board 630 may move in an arc rotation on top of the main printed circuit board 610. The RF transmission lines 613- 614 arc also arc shaped. As such, if the wiper printed circuit board 630 moves, for example, to the left in the view of FIG. ISA, then the length of the RF transmission path between input port 620 and output ports 621-622 are shortened, while the length of the RF transmission path between input port 620 and output ports 624-625 is increased. As increasing or decreasing the length of the RF transmission path results in a phase shift, it can be seen that by moving the wiper printed circuit board 630 to the left, the phase of the RF signal recei ved at four of the five output ports will be changed in the same manner as described above with respect to the high band phase shifter 500.

[0099] FIG. 16A is a front view of the phase shifter 600, and FIGS, 16B and 16C are enlarged views of portions of the main printed circuit board 610 mat are designed to facilitate attachment of solder clips. FIGS. 17A-17C are a front view, a left end view, and a right end view, respectively, of two of the low band phase shifters 600 of FIGS. 15A-15C mounted on a phase shifter mounting plate 680. As the solder clips used tor the low band phase shifters are substantially similar to the solder clips 550, 560 used with the high band phase shifters 500 that are described above (the primary difference being that the low band solder clips are designed to hold three cables each as opposed to four cables), and as the attachment mechanism to the main printed circuit board 610 is also substantially similar, further description of FIGS. 16A-16C and 17A-17C will be omitted.

[0100] FIGS. 18A-18B are a schematic perspective view and top view, respectively, of a RET assembly 700 included in the antenna of FIGS. 1A-1G.

[0101] FIGS. 19A-19E are a perspective view, an exploded perspective view, a side view a cross-sectional view and an end view of one of the RET units included in the RET assembly of FIGS. 18A-18B.

[0102] As shown in FIGS. 18ΑΛ8Β, the RET assembly 700 includes three RET units 720 that are mounted on a RET tray 710. As shown in FIGS. 19A-19E, each RET unit 720 includes a motor assembly 722, a drive screw 724, and a board assembly 730. Each RET unit 720 may drive a mechanical linkage (not shown). The distal end of the mechanical linkage may be connected to two phase shifters, namely phase shifters for the +45 degree array and the -45 degree array for a particular band or sub-band. Thus, a total of four RET units 720 may be provided in some embodiments that are used to control a total of eight phase shifters, including four low band phase shifters 600 (namely one low band phase shifter 600 tor each polarization for each of two sub-bands) and foUr high band phase shifters 500 (namely one high band phase shifter 500 for each polarization for each of the two high band arrays 230, 240). [0103] FIGS.20A-20C are a top view, a side view and a perspective view of the board assembly 730 included on the RET unit 720 of FIGS. 19A-19E that illustrate how the board assembly 730 is connected to the motor unit 722. FIG.20D is an enlarged view of a portion of FIG.20C FIGS.21A-21C are a top view, a perspective view, and an end view of the view a cross-sectional view and an end view of the board assembly 730 of FIGS.20 A- 200.

[0104] In some embodiments, the low band radiating elements 300 may be designed to operate across the full R-band frequency range. The R-band frequency range includes three sub-bands that are commonly referred to as the 700 MHz, 800 MHz and 900 MHz sub- bands, each of which support a different service. The antenna 100 described above may be designed to operate in two of these sub-bands such as, for example, the 700 MHz and 800 MHz sub-bands or the 800 MHz and 900 MHz sub-bands.

[0105] When the antenna 100 supports multiple sub-bands for the low-band radiating elements 300, diplexers may be used to combine/separate the RF signals in different of the sub-bands. As discussed above, the low band array 220 includes five sub-arrays that each have two radiating elements 300. Each sub-array of low band radiating elements (i.e., each feed board 250) may be connected by a coaxial cable to a diplexer. Since each feed board 250 is fed with two signals having orthogonal polarizations, a total of ten diplexers may be provided, namely five diplexers that provide the +45° polarized RF signals to the respective five sub _^ arrays, and five diplexers that provide the -45° polarized RF signals to the respective five sub-arrays. Each diplexer may separate the signal received from the radiating elements 300 based on frequency, outputting signals in, for example, the 700 MHz band through a first output port, and outputting signals in, for example, the 800 MHz band through a second output port. For each diplexer, the 700 MHz band output port may be connected to one of the output ports on a 700 MHz phase shifter 600 and the 800 MHz band output port may be connected tp one of the output ports on an 800 MHz phase shifter 600. Thus, in this example configuration two 700 MHz phase shifters 600 and two 800 MHz phase shifters 600 would be required. In other embodiments, diplexers may also or alternatively be provided for the high band radiating elements.

[0106] in some embodiments, a beam pointing determination module 900 may be included on the antenna 100. A beam pointing determination module refers to an active device that may be included in the base station antenna 100 that determines a physical pointing direction of the antenna. In an example embodiment, the beam pointing

determination module 900 uses a pair of GPS antennas and transceivers and an associated processor to figure out the azimuth and elevation mechanical pointing directions of the antenna 100 (i.e., the physical boresight of the antenna 100). As shown in FIG, 22, the beam pointing determination module 900 may be mounted directly on the top end of the reflector 214 during assembly of the antenna 100. The beam pointing determination module 900 may fit directly under the top end cap 112 in the assembled antenna 100.

[0107] In some embodiments, a fourth array of radiating elements may be added that is interleaved with the first array of radiating elements 220. In some embodiments, this fourth array of radiating elements may be designed to transmit and receive signals in a third frequency band such as, for example, the 1400 MHz frequency band. FIG. 23 illustrates (using crossed black lines and red boxes) the positions where the radiating elements of the fourth array may be interleaved with the low band radiating elements 300.

[0108] The base station antennas according to embodiments of the present invention may have a modular design philosophy where, across a large number of different antenna designs, common parts, common spacing of radiating elements and common build philosophies are used. This may expedite design time, provide for improved

manufacturability, and allow for volume costing.

[0109] In example embodiments, the dipole-to-fecd board assembly 250 that includes two low band radiating elements may be replicated multiple times in a given base station antenna and may also be used across multiple different base station antenna designs. Moreover, the dipole-to-feed board assemblies 250, 260, 270 may be designed for complete solder joint automation to decrease manufacturing costs and/or to provide improved performance and reliability.

[0110] Embodiments of the present invention have been described above with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art; Like numbers refer to like elements throughout

[0111] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

[0112] It will be understood that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present Other words used to describe the relationship between elements should be interpreted in a like fashion (Le„ "between" versus "directly between", "adjacent" versus "directly adjacent", etc.).

[0113] Relative terms such as "below" or "above" or "upper" or "lower" or

"horizontal" or "vertical" may be used herein to describe a relationship of one element, layer or region to another element layer or region as illustrated in the figures. It will be

understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures,

[0114] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. 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 herein, specify fee 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.

[0115] Aspects and elements of all of the embodiments disclosed above can be combined in any Way and/or combination with aspects or elements of other embodiments to provide a plurality of additional embodiments.