WO2023146720A1

WO2023146720A1 - Base station antennas

Info

Publication number: WO2023146720A1
Application number: PCT/US2022/082321
Authority: WO
Inventors: Nengbin Liu; Pengfei Guo; Xiaona KANG; Xun Zhang
Original assignee: Commscope Technologies Llc
Priority date: 2022-01-27
Filing date: 2022-12-23
Publication date: 2023-08-03

Abstract

Base station antennas include a sealably detachable rear panel with a lower dielectric constant and/or that is thinner than a front radome thereof. The rear panel can have a frequency selective surface and an array of low band radiating elements can project forward of the FSS. A mMIMO antenna array resides behind the FSS and is configured to transmit signal through the FSS and out the front radome of the base station antenna.

Description

BASE STATION ANTENNAS

BACKGROUND

[0001] The present invention generally relates to radio communications 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" which are served by respective base stations. The base station may include one or more antennas that are configured to provide two-way radio frequency ("RF") communications with mobile subscribers that are within the cell served by the base station. In many cases, each cell is divided into "sectors." In one common configuration, a hexagonally shaped cell is divided into three 120° sectors in the azimuth plane, and each sector is served by one or more base station antennas that have an azimuth Half Power Beam width (HPBW) of approximately 65°. Typically, the base station antennas are mounted on a tower or other raised structure, with the radiation patterns (also referred to herein as "antenna beams") that are generated by the base station antennas directed outwardly. Base station antennas are often implemented as linear or planar phased arrays of radiating elements.

[0003] In order to accommodate the increasing volume of cellular communications, cellular operators have added cellular service in a variety of new frequency bands. In order to increase capacity without further increasing the number of base station antennas, multi-band base station antennas have been introduced which include multiple linear arrays of radiating elements. Additionally, base station antennas are now being deployed that include "beamforming" arrays of radiating elements that include multiple columns of radiating elements that are connected to respective ports of a radio so that the antenna may perform active beamforming (i.e., the shapes of the antenna beams generated by the antenna may be adaptively changed to improve the performance of the antenna). In some cases, the radios for these beamforming arrays may be integrated into the antenna. These beamforming arrays typically operate in higher frequency bands, such as various portions of the 3.3-5.8 GHz frequency band. Antennas having integrated radios that can adjust the amplitude and/or phase of the sub-components of an RF signal that are transmitted through individual radiating elements or small groups thereof are referred to as "active antennas." Active antennas can generate narrowed beamwidth, high gain, antenna beams and can steer the generated antenna beams in different directions by changing the amplitudes and/or phases of the sub-components of RF signals that are transmitted through the antenna.

[0004] Further details of example conventional antennas can be found in co-pending WO2019/236203 and W02020/072880, the contents of which are hereby incorporated by reference as if recited in full herein.

[0005] With the development of wireless communication technology, an integrated base station antenna including a passive antenna device and active antenna device has emerged. The passive antenna device may include one or more arrays of radiating elements that are configured to generate relatively static antenna beams, such as antenna beams that are configured to cover a 120-degree sector (in the azimuth plane) of an integrated base station antenna. The arrays may include arrays that operate, for example, under second generation (2G), third generation (3G) or fourth generation (4G) cellular network standards. These arrays are not configured to perform active beamforming operations, although they typically have remote electronic tilt (RET) capabilities which allow the shape of the antenna beam to be changed via electromechanical means in order to change the coverage area of the antenna beam. The active antenna device may include one or more arrays of radiating elements that operate under fifth generation (5G or higher version) cellular network standards. In 5G mobile communication, the frequency range of communication includes a main frequency band (specific portion of the range 450 MHz - 6 GHz) and an extended frequency band (24 GHz - 73 GHz, i.e., millimeter wave frequency band, mainly 28 GHz, 39 GHz, 60 GHz and 73 GHz). The frequency range used in 5G mobile communication includes frequency bands that use higher frequencies than the previous generations of mobile communication. These arrays typically have individual amplitude and phase control over subsets of the radiating elements therein and perform active beamforming.

[0006] The active antenna device is capable of emitting high-frequency electromagnetic waves (for example, high-frequency electromagnetic waves in the 2.3 - 4.2 GHz frequency band or a portion thereof). At least a portion of the active antenna device is typically mounted rearwardly of the passive antenna device. Electromagnetic waves are transmitted through a front radome of the active antenna device and through a rear radome and front radome of the passive antenna device, which may hinder wave transmission of, for example, high-frequency electromagnetic waves emitted by the active antenna device. SUMMARY

[0007] Embodiments of the present invention are directed to base station antennas with a respective housing having a rear panel of a different material and/or that is thinner than a front radome thereof.

[0008] The rear panel can define a portion of a rear radome with a lower dielectric constant relative to the front radome.

[0009] The rear panel can include a frequency selective surface (FSS).

[00010] The rear panel can be sealably coupled to a rear of the base station antenna housing enclosing the passive antenna assembly.

[00011] The FSS can be configured to allow high band radiating elements to propagate electromagnetic waves therethrough and reflect lower band RF signals transmitted by lower band radiating elements projecting forward of the FSS.

[00012] The FSS can be provided, for example, by a printed circuit board defining a metal grid pattern (of metal patches), a sheet of metal provided with a grid pattern or a plastic substrate with a metallized grid pattern.

[00013] Where used, the grid pattern provided by the sheet of metal can be provided with an array of apertures devoid of metal or with metal patches that are configured to allow high band radiating elements with a film/cover whereby the grid pattern is configured to propagate electromagnetic waves through the apertures and reflect lower band RF signals transmitted by lower band radiating elements projecting forward of the FSS.

[00014] Embodiments of the present invention are directed to a base station antenna that includes a base station antenna housing having a front radome and a rear. The rear includes an open space that extends longitudinally a sub-length of the base station antenna housing and that extends laterally across at least 50% of a width of the base station antenna housing. The base station antenna also includes a passive antenna assembly in the base station antenna housing and a rear panel sealably coupled to the rear of the base station antenna housing and positioned to cover the open space. The rear panel has a different material than the front radome or comprises a material that is the same but thinner than the front radome.

[00015] The rear panel can have a frequency selective surface (FSS) that is configured to reflect or block electromagnetic waves from radiating elements of the passive antenna assembly and allow higher band electromagnetic waves to travel therethrough toward the front radome. [00016] The FSS can be defined by at least one sheet of metal arranged to provide a grid pattern.

[00017] The FSS can have a grid pattern of metal patches.

[00018] The FSS can have a metal pattern on/in/of a printed circuit board.

[00019] The FSS can be attached to a substrate formed of a sheet molding compound or polycarbonate.

[00020] A plurality of radiating elements can extend forward of an FSS in the base station antenna housing.

[00021] The plurality of radiating elements can include radiating elements that are configured to transmit and receive signals in at least a portion of the 6167-960 MHz frequency range.

[00022] The base station antenna can further include an active antenna module coupled to the base station antenna housing. The active antenna module can include an array of radiating elements facing an FSS and the array of radiating elements of the active antenna module can be configured to propagate RF energy through the rear panel.

[00023] The array of radiating elements of the active antenna module can be defined by and/or include a mMIMO array of radiating elements positioned behind the rear panel.

[00024] A lateral extent of the FSS can be a sub-distance of a lateral extent of the base station antenna housing.

[00025] The FSS, where used, can reside at an upper portion of the base station antenna housing, aligned with the array of radiating elements of the active antenna module. [00026] The FSS, where used, can be configured to allow RF energy to pass through at one or more defined frequency range and reflect RF energy at a different frequency band.

[00027] The active antenna module can have a radome and the radome of the active antenna module can abut or resides adjacent to and face the rear panel of the base station antenna housing.

[00028] The FSS, where used, can be configured to reflect RF energy at a low band and pass RF energy at a higher band.

[00029] The passive antenna assembly can include first and second linear arrays that are laterally spaced apart. The rear panel can be coupled to a main reflector of the passive antenna assembly. The FSS can define a backplane and/or reflector for at least some radiating elements of the first and second linear arrays.

[00030] At least some radiating elements can be coupled to and project forward of the FSS. [00031] The passive antenna assembly can include a plurality of linear arrays of radiating elements that extend in front of a reflector.

[00032] The base station antenna can further include an active antenna module coupled to the base station antenna housing with the rear panel in front of the active antenna module.

[00033] The rear panel can be detachably coupled to the rear of the base station antenna, and wherein a seal member resides between an outer perimeter of the rear panel and the rear of the base station antenna.

[00034] The rear panel can include and/or be formed of a sheet molding compound and/or a polycarbonate.

[00035] The rear panel can have an outer perimeter that has rearwardly extending walls surrounding a flat panel extending forward thereof.

[00036] The passive antenna assembly can have a main reflector portion that merges into a pair of laterally spaced apart right and left side reflector strips that face each other across an open space therebetween. At least a portion of the rear panel can extend in front of or behind the open space.

[00037] The reflector strips can reside in a plane that is behind a plane of the main reflector portion.

[00038] The rear panel can have rearwardly extending sidewalls that extend rearward of a seal interface surface of the rear panel.

[00039] Embodiments of the present invention are directed to a base station antenna assembly that includes: a base station antenna housing having a front radome; a plurality of columns of first radiating elements configured for operating in a first operational frequency band inside the base station antenna housing, each column of first radiating elements comprising a plurality of first radiating elements arranged in a longitudinal direction; and a rear panel detachably and sealably coupled to a rear of the base station antenna housing. The rear panel has a lower dielectric constant than the front radome.

[00040] The rear of the base station antenna housing can have an open space extending laterally and longitudinally. The rear panel can have right and left side walls that extend rearwardly from the base station antenna housing behind right and left side portions of the open space. The rear panel can cover the open space.

[00041] The rear panel can include a frequency selective surface (FSS) that resides behind the plurality of columns of first radiating elements. The FSS can be configured to reflect electromagnetic waves within the first operational frequency band. [00042] The base station antenna assembly can also include a plurality of columns of second radiating elements configured for operating in a second operational frequency band that can be different from and does not overlap with the first operational frequency band, each column of second radiating elements can have a plurality of second radiating elements arranged in the longitudinal direction. The FSS can be further configured such that electromagnetic waves within the second operational frequency band can propagate through the FSS.

[00043] The second operational frequency band can be higher than the first operational frequency band. The plurality of columns of second radiating elements can be provided by an active antenna module coupled to a rear of the base station antenna housing.

[00044] The FSS can be defined by a sheet of metal configured with an array of unit cells. The unit cells can have open center spaces devoid of metal that are surrounded by a perimeter of metal.

[00045] The FSS can be coupled to or provided by a multiple layer printed circuit board and comprises a grid pattern of metal patches.

[00046] The rear panel can define a backplane and/or reflector at a common ground with a primary reflector inside the base station antenna housing.

[00047] Low band radiating elements can be supported by the rear panel and can project forward of the FSS.

BRIEF DESCRIPTION OF THE DRAWINGS

[00048] FIG. l is a simplified cross-section view of a base station antenna with an active antenna module coupled to a housing enclosing a passive antenna assembly according to embodiments of the present invention.

[00049] FIG. 2 is a rear, side perspective view of an example base station antenna mounted to a mounting structure according to embodiments of the present invention.

[00050] FIG. 3 is a front, side perspective, partially exploded view of an example base station antenna with a housing and an internal passive antenna assembly and with a front radome shown transparent according to embodiments of the present invention.

[00051] FIG. 4A is a rear, side perspective, partially exploded view of the base station antenna shown in FIG. 3 according to embodiments of the present invention.

[00052] FIG. 4B is a rear, side perspective, partially exploded view of another embodiment of a base station antenna according to embodiments of the present invention. [00053] F IG. 5 is a front, side perspective, partially exploded view of another example base station antenna according to embodiments of the present invention.

[00054] FIG. 6 is a side view of a portion of the base station antenna housing illustrating an example passive antenna assembly according to embodiments of the present invention.

[00055] FIG. 7 is a lateral section schematic view illustrating a fixed front-to-back distance between a front radome and rear radome of a base station antenna housing residing in front of a radome of an active antenna module.

[00056] FIG. 8 is a simulated S parameter plot illustrating reflection associated with the configuration shown in FIG, 7.

[00057] FIG. 9 is a lateral section schematic view illustrating an adjustable front-to- back distance between a front radome and rear radome of a base station antenna housing residing in front of a radome of an active antenna module according to embodiments of the present invention,

[00058] F IG. 10 is a simulated S parameter plot illustrating reflection associated with the configuration shown in FIG. 9, showing lower reflection compared to the configuration shown in FIG. 8.

[00059] FIG. 11A is a rear, side perspective view of a two-piece configuration providing a portion of a base station antenna according to embodiments of the present invention.

[00060] FIG. 11B is an assembled view of the two-piece configuration shown in FIG.

11A

[00061] FIG. 12 is an enlarged lateral section view of the assembled configuration shown in FIG. 11B with a front radome according to embodiments of the present invention. [00062] FIG. 13 is a front, side perspective, partially exploded view of the base station antenna shown in FIG. 12.

[00063] FIG. 14 is a rear, side perspective, partially exploded view of the base station antenna shown in FIG. 13.

[00064] FIG. 15 is a schematic illustration of example components of a portion of the antenna assembly of the base station antenna shown in FIG. 13 according to embodiments of the present invention.

[00065] FIG. 16 is an enlarged view of an example connector configuration for the dipole assembly and phase shifter connection shown in FIG. 15. [00066] F IG. 17A is a front view of an example FSS grid for a base station antenna according to embodiments of the present invention.

[00067] FIG. 17B is a greatly enlarged front view of a unit cell of the grid of the FSS shown in FIG. 17A.

[00068] F IG. 17C is a greatly enlarged front view of another example of a unit cell of the grid of the FSS shown in FIG. 17A.

[00069] FIG. 17D is a greatly enlarged front view of another example of a unit cell of the grid of the FSS shown in FIG. 17A.

DEI AILED DESCRIPTION

[00070] Embodiments of the present invention are directed to base station antennas. In the description that follows, these base station antennas will be described using terms that assume that the base station antenna is mounted for use on a tower, pole or other mounting structure with the longitudinal axis of the base station antenna extending along a vertical axis and the front of the base station antenna mounted opposite the tower, pole or other mounting structure pointing toward the target coverage area for the base station antenna. It will be appreciated that the base station antennas may not always be mounted so that the longitudinal axes thereof extend along a vertical axis. For example, the base station antennas may be tilted slightly (e.g., less than 10°) with respect to the vertical axis so that the resultant antenna beams formed by the base station antennas each have a small mechanical downtilt.

[00071] FIG. 1 illustrates a base station antenna 100. The base station antenna 100 has a housing lOOh that holds a passive antenna assembly 190 (FIGs. 3, 6) and that can couple to or include at least one active antenna module 110. The term “active antenna module” is used interchangeably with “active antenna unit” and “ AAU” and refers to a cellular communications unit comprising radio circuitry and associated radiating elements. The radio circuitry is capable of electronically adjusting the amplitude and/or phase of the subcomponents of an RF signal that are output to different radiating elements of an array of radiating elements or groups thereof. The active antenna module 110 may include both the radio circuitry and a radiating element array (e.g., a multi-input-multi-output (mMIMO) beamforming antenna array) and may include other components such as filters, a calibration network, an antenna interface signal group (AISG) controller and the like. The active antenna module 110 can be provided as a single integrated unit or provided as a plurality of stackable units, including, for example, first and second sub-units such as a radio sub-unit (box) with the radio circuitry and an antenna sub-unit (box) with a multi-column array of radiating elements. The first and second sub-units can stackably attach together, in a front to back direction of the base station antenna 100, with the radiating element array 1190 closer to the front 11 If of the housing lOOh/radome 111 of base station antenna 100 than the radio circuitry unit 1120. The rear surface lOOr of the base station antenna housing lOOh can have a pair of rails 210 that can be used to mount the active antenna module 110 thereto. As shown, the rails 210 can be longitudinally extending rails but laterally extending rails or combinations of laterally extending and longitudinally extending rails may be provided, where such rails are used. A frame 112 can be used to mount the AAU 110 to the housing lOOh via rails 210. However, other mounting configurations are contemplated as will be appreciated by those of skill in the art.

[00072] As will be discussed further below, the base station antenna 100 includes an antenna assembly 190 (FIGs. 3-5, 9) inside the housing lOOh, which can be referred to as a “passive antenna assembly”. The term “passive antenna assembly” refers to an antenna assembly having one or more arrays of radiating elements that are coupled to radios that are external to the antenna assembly, typically remote radio heads that are mounted in close proximity to the base station antenna housing lOOh. The arrays of radiating elements included in the passive antenna assembly 190 (FIG. 6) are configured to form static antenna beams (e.g., antenna beams that are each configured to cover a sector of a base station). The passive antenna assembly 190 may comprise a backplane provided by a reflector 170, with radiating elements projecting in front of the reflector and the radiating elements can include one or more linear arrays of low band radiating elements that operate in all or part of the 617- 960 MHz frequency band and/or one or more linear arrays of mid-band radiating elements that operate in all or part of the 1427-2690 MHz frequency band. The passive antenna assembly 190 (FIG. 9) is mounted in the housing lOOh of base station antenna 100 and one or more active antenna modules 110 can releasably (detachably) couple (e.g., directly or indirectly attach) to a back of the base station antenna housing lOOh.

[00073] Referring to FIGs. 1-5, the base station antenna 100 has a housing lOOh. The housing lOOh may be substantially rectangular with a flat rectangular cross-section. At least a front side of the housing lOOh may be implemented as a radome 111 providing a front radome 11 If. A “radome” refers to a dielectric cover that allows RF energy to pass through in certain frequency bands. A rear lOOr of the housing lOOh may also include a rear radome lllr that is opposite the front radome 11 If. Optionally, the housing lOOh and/or the radome 111 can also comprise two (narrow) sidewalls 100s providing side radomes Ills facing each other and extending rearwardly between the front radome 11 If and the rear radome lllr. The sidewalls 100s, Ills can have a width, measured in a front-to-back direction, that is 40%-90% less than a lateral extent of the housing lOOh.

[00074] The top side lOOt of the housing lOOh may be sealed in a waterproof manner and may comprise an end cap 120 and the bottom side 100b of the housing lOOh may be sealed with a separate end cap 130 with RF ports 140.

[00075] The front side, at least part of the sidewalls and typically at least part of the rear side of the housing lOOh are typically implemented as radomes that are substantially transparent to RF energy within the operating frequency bands of the passive antenna assembly 190 and active antenna module 110. At least part of the radome 111 may be formed of, for example, fiberglass or plastic.

[00076] As shown by the arrows in FIG. 1, radiation (electromagnetic waves) transmitted by the array of radiating elements in the active antenna 1190 can transmit through the front radome IlOf of the active antenna module 110, enter the housing lOOh from the back lOOr and transmit out the front radome 11 If, thus traveling through at least three radome walls spaced apart in a front-to-back direction.

[00077] Referring to FIGs. 2-5, for example, to facilitate the electromagnetic wave transmission from the AAU 110 and/or minimize loss, a portion or segment of the rear lOOr of the housing lOOh can be coupled to a (rear) panel 150 that has a different material and/or a thinner thickness than the front radome lllr. The rear panel 150 can be formed of a material or substrate that has a lower dielectric constant than the front radome 11 If.

[00078] The rear panel 150 can be detachably coupled to the rear lOOr of the base station antenna housing lOOh. The rear panel 150 can define a portion of the rear radome llOr and can extend laterally across at least 50% of a width Wi of the base station antenna housing lOOh, typically in a width Withat is in range of about 50%-95% of the width Wi of the base station antenna housing lOOh. The rear panel 150 can extend longitudinally a sublength L2 of a length Li of the base station antenna housing lOOh. The sub-length Li can be 20-70% of the length of the housing lOOh, in some embodiments.

[00079] Because the rear panel 150 is not required to provide structural support for the base station antenna housing lOOh, it can have a thinner material thickness than a rear wall of the rear lOOr of the housing lOOu thereunder and/or thereabove.

[00080] The rear panel 150 can extend over an open space or window 272 in the rear lOOr of the base station antenna housing lOOh. The rear panel 150 can sealably attach to the rear lOOr of the base station antenna housing lOOh, covering the open space or window 272. The rear panel 150 can be rectangular in shape, as shown. However, other shapes are contemplated.

[00081] The rear panel 150 can cooperate with a seal 158 such as a gasket, O-ring, grommet or other seal member and/or configuration to provide a waterproof interface with the rear lOOr of the housing lOOh. Fasteners 159, such as waterproof rivets, positioned about an outer perimeter 150p of the rear panel 150 can be used to attach the rear panel 150 to the housing lOOh. The seal member 158 can reside inside the housing lOOh and/or outside the housing lOOh and cooperate with the rear panel 150 and rear lOOr of the housing lOOh to provide a watertight seal. The seal member 158 can be provided as both an internal seal member and an external seal member for additional seal integrity (not shown).

[00082] The front radome 11 If can be provided as a fiberglass material. The rear panel 150 can comprise a substrate formed of a different material than the front radome 11 If, such as, for example, a polycarbonate (“PC”) and/or sheet molding compound (SMC) configured to allow electromagnetic waves of the active antenna array 1190 (FIG. 1) to propagate therethrough with lower loss compared to a substrate formed of fiberglass in a thickness corresponding to that of the front radome 11 If.

[00083] The rear panel 150 can comprise a frequency selective surface (“FSS”) 155. The FSS 155 can have a grid pattern 155g. The FSS 155 can face into the base station antenna housing lOOh.

[00084] The FSS 155 can be provided in various manners. In some embodiments, the FSS 155 may be mounted on a suitable substrate such as, for example, a printed circuit board, PC and/or SMC. In some embodiments, the FSS can be arranged as a grid pattern 155g of metallic patches in one or more layers over and/or behind one or more dielectric layers, which may be provided by a multiple layer printed circuit board. The FSS 155 can alternatively be provided by a grid pattern 115g arranged in sheet metal as will be discussed further below.

[00085] Referring to FIG. 3, a reflector 170 in the housing lOOh can have a portion with longitudinally extending right and left strip segments 170r, 170Z (right and left directions are based on directions when looking from a front lOOf of the base station antenna 100) separated by an open space 172 that extends laterally and longitudinally between the strip segments 170r, 170Z.

[00086] The open space 172 between right and left side reflector segments 170r, 170Z can reside in front of the open space or window 272 in the rear lOOr of the housing lOOh. The open space 172 of the reflector and/or the open space 272 of the rear wall lOOr and the rear panel 150 can also reside in front of radiating elements of the (mMIMO array) active antenna 1190 (FIG. 1) of the active antenna module 110 (FIG. 1).

[00087] Active antenna modules 110 are often configured to operate using time division duplexing multiple access schemes in which the transmit and receive signals do not overlap in time, but instead the active antenna module transmits RF signals during selected time slots and receives RF signals during other time slots. The passive antenna assembly 190 can operate under frequency division duplexing (FDD) multiple access schemes.

[00088] The front IlOf of the active antenna module 110 can abut a primary surface of the rear panel 150 of the base station antenna housing lOOh or be closely spaced apart therefrom, typically within 1-50 mm, more typically in a range of about 5 mm-25 mm.

[00089] The FSS 155 can be configured to allow high band radiating elements (typically located in the active antenna module 110) to propagate electromagnetic waves therethrough and to reflect lower band RF signals (lower band electromagnetic waves) from lower band radiating elements projecting forward of the FSS 155.

[00090] The reflector 170 of the base station antenna housing lOOh can also have a FSS in front of the FSS 155 of the rear panel 150 instead of the open space 172. See, e.g., U.S. Patent Application Serial No. 17/468,783 and U.S. Provisional Patent Application Serial No. 63/236,727, for examples of reflector configurations, the contents of which are hereby incorporated by reference as if recited in full herein.

[00091] FIGs. 3-5 illustrate that the rear panel 150 can have a rectangular shape, with a long side extending longitudinally. However, as noted above, other shapes are contemplated. FIG. 4A illustrates that the rear panel 150 has opposing primary front and rear surfaces that are flat 150f. This configuration can arrange the FSS 155 to be parallel to, typically coplanar with the rear wall lOOr. The FSS 155 can be adjacent thereto, flush or extending behind the rear wall lOOr.

[00092] FIG. 4B illustrates that the rear panel 150 can have a box shape with rearwardly extending sidewalls 151, a rearwardly extending top wall 152 and a rearwardly extending bottom wall 153, extending at least partially behind the FSS 155. The seal member 158 can extend between a rear seal interface (frame) surface 154 that can frame the walls 151, 152, 153, inside thereof. The walls 151, 152, 153 can be rearwardly extending walls that surround a flat panel 150f extending forward thereof.

[00093] This configuration can arrange the FSS 155 to extend inwardly a distance in front of the rear wall lOOr of the base station antenna housing lOOh. The rearwardly extending length L3 of the walls 151, 152, 153, in a front-to-back direction, can be adjusted or fabricated to optimize the location of the FSS 155 relative to the front IlOf of the active antenna module 110 and/or the front radome 11 If thereby allowing the position of the FSS 155 to be adjusted relative to the front IlOf of the active antenna module 110 and/or the front radome 11 If.

[00094] FIG. 5 illustrates that the rear panel 150’ can have or be coupled to sidewalls 151 with rearwardly extending segments 151e that extend rearward past the seal interface 154 a distance sufficient to extend about sidewalls of the active antenna module 110. The sidewalls 151, or at least the rearwardly segments 151e, can be electrically conductive. The sidewalls 151 and/or sidewall segments 151e can provide a passive intermodulation (PIM) shield between the base station antenna housing lOOh and the AAU 110. The top and bottom walls 152, 153, respective, may optionally have rearwardly extending segments or extensions 152e, 153e, respectively, as well. The top and bottom walls 152, 153 may terminate at the seal interface 154 without extending further rearwardly.

[00095] The sidewalls 151 and/or sidewall segments 151e can electrically couple to internal components of the AAU 110, such as to electrically couple (e.g., capacitively or galvanically couple) via an outer wall or component thereof to an internal backplane or internal reflector of the AAU 110.

[00096] As discussed above, where the rear panel 150 comprises the FSS 155, the FSS 155 can be provided by any suitable material(s) such as, for example, a printed circuit board with a metal grid pattern of metal patches, a non-metallic substrate comprising a metallized surface in a grid pattern 155g or a sheet or sheets of metal provided with a grid pattern 155g. [00097] The grid pattern 155g can be arranged in any suitable manner and may be symmetric or asymmetric across a width and/or length of the FSS 155. Unit cells of the grid pattern 155g may be the same across and along the FSS 155 or may have different shapes and/or sizes.

[00098] Where used, the FSS 155 can comprise, in some embodiments, metamaterial, a suitable RF material or even air (although air may require a more complex assembly). The term “metamaterial” refers to composite electromagnetic (EM) materials. Metamaterials may comprise sub -wavelength periodic microstructures.

[00099] The FSS 155 can be provided as one or more cooperating layers. In some embodiments, the FSS 155 can include a substrate that has a dielectric constant in a range of about 2-4, such as about 3.7 and a thickness of about 5 mil and metal patterns formed on the dielectric substrate. The thickness can vary but thinner materials can provide lower loss. [000100] The FSS 155 can be configured to allow RF energy (electromagnetic waves) to pass through at one or more first defined frequency band and that is configured to reflect RF energy at a different second frequency band. Thus, the FSS 155 can reside behind at least some antenna elements of the passive antenna assembly 190 and can selectively reject some frequency bands and permit other frequency bands such as those of the antenna elements of the active antenna 1190 to pass therethrough by including the frequency selective surface and/or substrate to operate as a type of “spatial filter”.

[000101] A discussion of some example FSSs can be found in Ben A. Munk, Frequency Selective Surfaces: Theory and Design, ISBN: 978-0-471-37047-5;

DOI: 10.1002/0471723770; April 2000, Copyright © 2000 John Wiley & Sons, Inc., the contents of which are hereby incorporated by reference as if recited in full herein. See also, co-pending U.S. Patent Application Serial Number 17/468,783, the contents of which are also incorporated by reference as if recited in full herein.

[000102] The rear panel 150 can define a radome sub-segment of the rear lOOr of the base station antenna housing lOOh that extends between the front radome 11 If and the front IlOf of the active antenna module 110.

[000103] The FSS 155 can be in front or behind and parallel to laterally extending segments of the right and left sides 170r, 170Z of the reflector 170.

[000104] All or part of the right and left side walls 151 of the rear panel 150 can be electrically insulating.

[000105] Alternatively, all or part of the right and left rearwardly extending sidewalls 151 can be electrically conductive and comprise metal, such as aluminum or aluminum alloy. The side walls 151 can be electronically coupled to one or more components in the active antenna module 110 and/or the reflector 170, such as galvanically or capacitively coupled thereto.

[000106] In some embodiments, the FSS 155 can be configured to act like a High Pass Filter essentially allowing mid band and/or low band energy <2.7 MHz, to substantially reflect (the FSS can act like a sheet of metal) while allowing higher band energy, for example, about 3.5 GHz or greater, to substantially pass through. Thus, the FSS 155 is transparent or invisible to the higher band energy and a suitable out of band rejection response from the FSS can be achieved. The FSS 155 may allow a reduction in filters or even eliminate filter requirements for looking back into the radio 1120.

[000107] In some embodiments, the FSS 155 may be implemented by forming the frequency selective surface on a printed circuit board, optionally a flex circuit board. In some embodiments, a multi-layer printed circuit board can comprise one or more layers which form the FSS 155 configured such that electromagnetic waves within a predetermined frequency range cannot propagate therethrough and with one or more other predetermined frequency range associated with the one or more layers of the multi-layer printed circuit board is allowed to pass therethrough. The grid pattern 155g can comprise shaped metal patches of any suitable geometry.

[000108] In some embodiments, the FSS 155 is provided by a sheet or sheets of metal that is/are stamped, punched, acid etched, or otherwise formed to provide a grid pattern 155g. The grid pattern 155g can be configured to have closed or open unit cells 1305 of any suitable geometry.

[000109] Referring to FIGs. 17A-17C, where used, the grid pattern 155g provided by the sheet(s) of metal can be provided with an array of unit cells 1305 with shaped metal patches 1310 (FIG. 17B) that are provided as closed surface metal patches and/or shaped metal patches with open apertures 1310a devoid of metal surrounded by metal perimeters 1310p (FIG. 17C) that are configured to allow high band radiating elements to propagate electromagnetic waves and reflect low band signal from low band radiating elements projecting forward of the grid pattern 155g. The unit cells 1305 can have an axis of symmetry A-A about a center point Cp. Thus, in some embodiments, the FSS 155 is defined by/provided as a metal grid with an array of unit cells 1305. The unit cells 1305 can have an open center interior devoid of metal and each unit cell can include a metal outer perimeter. The unit cells 1305 can have a metal patch configuration with metal centers merging into metal outer perimeters. The FSS 155 can be provided as a single layer of sheet metal providing the grid pattern 155g with the unit cells and with the open centers or interiors devoid of metal. For further discussion of metal grids, see copending U.S. Provisional Application Serial Number 63/254,446, the contents of which are hereby incorporated by reference as if recited in full herein.

[000110] In some embodiments, the open centers Cp can be open to atmosphere/local environmental conditions. In other embodiments, the FSS 155 can comprise a cover 2305 extending over the unit cells 1305 as shown in FIG. 13D. The cover can be a dielectric cover and can comprise fiberglass, a printed circuit board, a film, and/or a plastic, such as polymer or copolymer. The cover 2305 on metal grids 155g may improve low and/or mid band reflection. The cover 2305 may be attached to the FSS 155 to extend over (in front of and/or behind) each unit cell 1305. [000111] Referring to FIG. 2, in some embodiments, an active antenna module 110 can attach to the base station antenna 100 using a frame 112 and accessory mounting brackets 113, 114. The rear side lOOr of the housing lOOh may be a flat surface extending along a common plane over an entire longitudinal extent thereof or along at least a portion of the longitudinal extent thereof. The rear surface lOOr can comprise a plurality of longitudinally spaced apart mounting structure brackets, shown as upper and lower brackets, 115, 116, respectively, that extend rearwardly from the housing lOOh. In some embodiments, the mounting structure brackets 115, 116 may be configured to couple to one or more mounting structures 10 such as, for example, a tower, pole or building. At least two of the mounting structure brackets 115, 116 can also be configured to attach to the frame 112 of the base station antenna arrangement, where used. The frame 112 may extend over a sub-length of a longitudinal extent L of base station antenna 100, where the sub-length is shown in FIG. 3 as being at least a major portion thereof (at least 50% of a length thereof). The frame 112 can comprise a top 112t, a bottom 112b and two opposing long sides 112s that extend between the top 112t and the bottom 112b. The frame 112 can have an open center space 112c extending laterally between the sides 112s and longitudinally between the top 112t and bottom 112b.

[000112] The frame 112, where used, may be configured so that a variety of different active antenna modules 110 can be mounted to the frame 112 using appropriate accessory mounting brackets 113, 114. As such, a variety of active antenna modules 110 may be interchangeably attached to the same base station antenna 100. While the frame 112 is shown by way of example, other mounting systems may be used.

[000113] In some embodiments, a plurality of active antenna modules 110 may be concurrently attached to the same base station antenna 100 at different longitudinal locations using one or more frames 112. Such active antenna modules 110 may have different dimensions, for example, different lengths and/or different widths and/or different thicknesses.

[000114] Turning now to FIG. 6, an example passive antenna assembly 190 is shown. The reflector 170 can have a first (shown as upper) portion with the spaced apart right and left strips or sides 170r, 170Z and can merge into a primary reflector portion 214 that extends longitudinally and laterally. The primary reflector portion 214 may have a longitudinal length that is greater than a longitudinal length of the strips 170r, 170Z. The primary reflector 214 can have a solid reflection surface for antenna elements residing in front of the primary reflector 214 and may reside over operational components 314, such as filters, tilt adjusters and the like. The primary reflector portion 214 can extend forwardly of and be co-planar with the first reflector portion 170a. The reflector 170 and the primary reflector 214 may comprise a single monolithic structure in some embodiments.

[000115] A first reflector portion at an upper portion of the base station antenna 100 can include the strips 170r, 170Z and can reside a distance in a range of 1/8 wavelength to 14 wavelength of an operating wavelength behind radiating elements in the linear arrays. The radiating elements, may comprise, for example, radiating elements 222, in some embodiments. The term "operating wavelength" refers to the wavelength corresponding to the center frequency of the operating frequency band of the radiating element, e.g., a low band radiating element 222. The first reflector portion 170r, 170Z can reside a distance in a range of 1/10 wavelength to 1/2 wavelength of an operating wavelength in front of the array of (high band) radiating elements 1195 of the active antenna module 110 in some embodiments. By way of example, in some particular embodiments, the reflector portion 170r, 170Z can reside a physical distance of 0.25 inches and 2 inches from a ground plane or reflector that is behind a mMIMO array of radiating elements 1195 of the active antenna 1190 of the active antenna module 110. Other placement positions may be used.

[000116] In some embodiments, the ground plane or reflector of the active antenna module 110 can be electrically coupled to the reflector 170r, 170Z and/or primary reflector 214 of the base station antenna 100, such as galvanically and/or capacitively coupled. In other embodiments, the ground plane or reflector of the active antenna module 110 is not electrically coupled to the reflector 170, e.g., reflector strips 170r, 170Z and/or primary reflector 214.

[000117] The passive antenna assembly 190 comprises multiple arrays of radiating elements, typically provided in columns, with radiating elements that extend forwardly from the primary reflector 214, with some columns of radiating elements continuing to extend in front of the front side of the reflector strips 170r, 170Z and/or rear panel 150. The arrays of radiating elements of the antenna assembly 190 may comprise radiating elements 222 that are configured to operate in a first frequency band and radiating elements 232 that are configured to operate in a second frequency band. Other arrays of radiating elements may comprise radiating elements that are configured to operate in either the second frequency band or in a third frequency band. The first, second and third frequency bands may be different frequency bands (although potentially overlapping). In some embodiments, low band radiating elements 222 that are configured to operate in some or all of the 617-960 MHz frequency band) can reside in front of and along right and left side portions 170r, 170Z of the reflector 170 and/or right and left sides of the primary reflector 214.

[000118] Some of the radiating elements of the antenna 100 may be mounted to extend forwardly from the primary reflector 214, and, if dipole-based radiating elements are used, the dipole radiators of these radiating elements may be mounted approximately 14 of a wavelength of the operating frequency for each radiating element forwardly of the main reflector 214. The main reflector 214 may serve as a reflector and as a ground plane for the radiating elements of the base station antenna 100 that are mounted thereon.

[000119] Still referring to FIG. 6, the passive antenna assembly 190 of the base station antenna 100 can include one or more arrays 220 of low-band radiating elements 222, one or more arrays of first mid-band radiating elements 232, one or more arrays of second mid-band radiating elements 242 and optionally one or more arrays of high-band radiating elements 252. The radiating elements 222, 232, 242, 252, 1195 may each be dual-polarized radiating elements. Further details of radiating elements can be found in co-pending WO2019/236203 and W02020/072880, the contents of which are hereby incorporated by reference as if recited in full herein. Some of the high band radiating elements, such as radiating elements 1195, can be provided as a mMIMO antenna array and may be provided in the active antenna module 110.

[000120] The low-band radiating elements 222 can be mounted to extend forwardly from the main or primary reflector 214 and one or both of the reflector strips 170r, 170Z and/or rear panel 150 and can be mounted in two columns to form two linear arrays 220 of low-band radiating elements 222. Each low-band linear array 220 may extend along substantially the full length of the antenna 100 in some embodiments.

[000121] The low-band radiating elements 222 may be configured to transmit and receive signals in a first frequency band. In some embodiments, the first frequency band may comprise the 617-960 MHz frequency range or a portion thereof (e.g., the 617-896 MHz frequency band, the 696-960 MHz frequency band, etc.). The low-band linear arrays 220 may or may not be used to transmit and receive signals in the same portion of the first frequency band. For example, in one embodiment, the low-band radiating elements 222 in a first linear array 220 may be used to transmit and receive signals in the 700 MHz frequency band and the low-band radiating elements 222 in a second linear array 220 may be used to transmit and receive signals in the 800 MHz frequency band. In other embodiments, the low- band radiating elements 222 in both the first and second linear arrays may be used to transmit and receive signals in the 700 MHz (or 800 MHz) frequency band (e.g., to support 4xMIM0 operation).

[000122] The first mid-band radiating elements 232 may likewise be mounted to extend forwardly from the main reflector 214 and/or reflector strips 170r, 1701 and/or the rear panel 150 and may be mounted in columns to form linear arrays of first mid-band radiating elements 232. The linear arrays of first mid-band radiating elements 232 may extend along the respective sides of the reflector 170 and/or the main reflector 214. The first mid-band radiating elements 232 may be configured to transmit and receive signals in a second frequency band. In some embodiments, the second frequency band may comprise the 1427- 2690 MHz frequency range or a portion thereof (e.g., the 1710-2200 MHz frequency band, the 2300-2690 MHz frequency band, etc.). In the depicted embodiment, the first mid-band radiating elements 232 are configured to transmit and receive signals in the lower portion of the second frequency band (e.g., some or all of the 1427-2200 MHz frequency band). The linear arrays of first mid-band radiating elements 232 may be configured to transmit and receive signals in the same portion of the second frequency band or in different portions of the second frequency band.

[000123] The second mid-band radiating elements 242 can be mounted in columns to form linear arrays 240 of second mid-band radiating elements 242. The second mid-band radiating elements 242 may be configured to transmit and receive signals in the second frequency band. In the depicted embodiment, the second mid-band radiating elements 242 are configured to transmit and receive signals in an upper portion of the second frequency band (e.g., some, or all, of the 2300-2700 MHz frequency band). In the depicted embodiment, the second mid-band radiating elements 242 may have a different design than the first mid-band radiating elements 232.

[000124] The high-band radiating elements 252 and/or 1195 can be mounted in columns in the upper medial or center portion of antenna 100 to form a multi-column (e.g., four or eight column) array 250 of high-band radiating elements 252 and/or 1195. The high-band radiating elements 1195 may be configured to transmit and receive signals in a third frequency band. In some embodiments, the third frequency band may comprise the 3300- 4200 MHz frequency range or a portion thereof.

[000125] In the depicted embodiment, the arrays 220 of low-band radiating elements 222, the arrays of first mid-band radiating elements 232, and the arrays of second mid-band radiating elements 242 are all part of the passive antenna assembly 190, while the array of high-band radiating elements 1195 are part of the active antenna module 110. It will be appreciated that the types of arrays included in the passive antenna assembly 190, and/or the active antenna module 110 may be varied in other embodiments.

[000126] It will also be appreciated that the number of linear arrays of low-band, midband and high-band radiating elements may be varied from what is shown in the figures. For example, the number of linear arrays of each type of radiating elements may be varied from what is shown, some types of linear arrays may be omitted and/or other types of arrays may be added, the number of radiating elements per array may be varied from what is shown, and/or the arrays may be arranged differently. As one specific example, two linear arrays of second mid-band radiating elements 242 may be replaced with four linear arrays of ultra- high-band radiating elements that transmit and receive signals in a 5 GHz frequency band. [000127] At least some of the low-band and mid-band radiating elements 222, 232, 242 may be mounted to extend forwardly of and/or from rear panel 150, the reflector strips 170r, 170Z or the primary/main reflector 214.

[000128] Each array 220 of low-band radiating elements 222 may be used to form a pair of antenna beams, namely an antenna beam for each of the two polarizations at which the dual-polarized radiating elements are designed to transmit and receive RF signals. Likewise, each array of first mid-band radiating elements 232, and each array of second mid-band radiating elements 242 may be configured to form a pair of antenna beams, namely an antenna beam for each of the two polarizations at which the dual-polarized radiating elements are designed to transmit and receive RF signals. Each linear array may be configured to provide service to a sector of a base station. For example, each linear array may be configured to provide coverage to approximately 120° in the azimuth plane so that the base station antenna 100 may act as a sector antenna for a three-sector base station. Of course, it will be appreciated that the linear arrays may be configured to provide coverage over different azimuth beamwidths. While all of the radiating elements 222, 232, 242, 252, 1195 can be dual-polarized radiating elements in the depicted embodiments, it will be appreciated that in other embodiments some or all of the dual-polarized radiating elements may be replaced with single-polarized radiating elements. It will also be appreciated that while the radiating elements are illustrated as dipole radiating elements in the depicted embodiment, other types of radiating elements such as, for example, patch radiating elements may be used in other embodiments.

[000129] Some or all of the radiating elements 222, 232, 242, 252, 1195 may be mounted on feed boards that couple RF signals to and from the individual radiating elements 222, 232, 242, 252, 1195, with one or more radiating elements 222, 232, 242, 252, 1195 mounted on each feed board. Cables (not shown) and/or connectors may be used to connect each feed board to other components of the antenna 100 such as diplexers, phase shifters, calibration boards or the like.

[000130] RF connectors or "ports" 140 (FIGs. 4A, 6) can be mounted in the bottom end cap 130 that are used to couple RF signals from external remote radio units (not shown) to the arrays of the passive antenna assembly 190. Two RF ports can be provided for each array, namely a first RF port 140 that couples first polarization RF signals between the remote radio unit and the arrays and a second RF port 140 that couples second polarization RF signals between the remote radio unit and the arrays. As the radiating elements 222, 232, 242 can be slant cross-dipole radiating elements, the first and second polarizations may be a - 45° polarization and a +45° polarization.

[000131] A phase shifter may be connected to a respective one of the RF ports 140. The phase shifters may be implemented as, for example, wiper arc phase shifters such as the phase shifters disclosed in U.S. Patent No. 7,907,096 to Timofeev, the disclosure of which is hereby incorporated herein in its entirety. A mechanical linkage may be coupled to a RET actuator (not shown). The RET actuator may apply a force to the mechanical linkage which in turn adjusts a moveable element on the phase shifter in order to electronically adjust the downtilt angles of antenna beams that are generated by the one or more of the low-band or mid-band linear arrays.

[000132] It should be noted that a multi-connector RF port (also referred to as a "cluster" connector) can be used as opposed to individual RF ports 140. Suitable cluster connectors are disclosed in U.S. Patent Application Serial No. 16/375,530, filed April 4, 2019, the entire content of which is incorporated herein by reference.

[000133] Referring to FIG. 3, feed boards 1200 can be provided in front of or behind the side segments of the primary reflector 214 and/or reflector strips 170r, 170Z. The feed boards 1200 connect to feed stalks of radiating elements 222 (such as low band elements). The feed stalks can be angled feed stalks that project outwardly and laterally inward to position the front end of the feed stalks closer to center of the reflector strips 170r, 170Z than a rearward end. The feed boards 1200 can be coupled and/or connected to the (upper) reflector 170 and/or to the primary reflector 214.

[000134] The radiating elements 220 can be dipole elements configured to operate in some or all the 617-960 MHz frequency band. Further discussions of example antenna elements including antenna elements comprising feed stalks can be found in U.S. Provisional Patent Application Serial Numbers 63/087,451 and 62/993,925 and/or related utility patent applications claiming priority thereto, the contents of which are hereby incorporated by reference as if recited in full herein.

[000135] Some, or all, of the low or mid-band radiating elements 222, 232, respectively, may be mounted on the feed boards 1200 and can couple RF signals to and from the individual radiating elements 222, 232. Cables (not shown) and/or connectors may be used to connect each feed board 1200 to other components of the base station antenna 100 such as diplexers, phase shifters, calibration boards or the like.

[000136] Referring now to FIGs. 7 and 8, in conventional configurations, the front radome 11 If resides at a distance DI from the back radome lllr and both are formed of fiberglass. The active antenna module 110 resides behind the back radome lllr. The simulated S parameter plot in FIG. 8 models the configuration of FIG. 7 and shows the return loss (the lower three curves) and the normalized power (the upper three curves) as a function of frequency for three different scan angles in the azimuth plane. The return loss is greater than -lOdb within the operating frequency band at two of the three scan angles.

[000137] FIG. 9 shows that the distance DI can be optimized/improved by using the rear panel 150 to form part of the rear radome lllr. This distance DI can be provided as a ?t/4 multiple or other wavelength or wavelength multiple to improve reflection. FIG. 10 is a simulated S parameter plot that shows the return loss (the lower three curves) and the normalized transmitted power (the upper three curves) as a function of frequency for the same three scan angles in the azimuth plane, similar to FIG. 8, but as shown in FIG. 9, with the rear radome lllr provided by a rear panel 150 with a low dielectric constant and/or with FSS 155. FIG. 10 shows there is lower reflection and improved return loss compared to FIG. 8. Return loss refers to when an RF signal is sent and there is poor impedance match, signal can reflect back from the second substrate/medium.

[000138] Turning now to FIGs. 11 A, 11B and 12-15, in some embodiments, the rear panel 150” can be configured to define a backplane that is electrically coupled to the main reflector 214 to provide a common ground plane and that can support radiating elements 222. The feed stalks 222f can project forward from the rear panel 150. The passive antenna assembly 190 can have a first portion with the primary reflector 214 that can attach to the rear panel 150” providing a backplane 150b and/or second reflector portion for radiating elements of the passive antenna assembly 190 and that is longitudinally spaced apart from the main reflector 214.

[000139] The main reflector 214 is in front of and over operational components 314, such as filters, tilt adjusters and the like. A connecting portion or member 171 can be used to capacitively or galvanically couple the rear panel 150” and the main reflector 214 so that they are at a common ground plane. The rear panel 150” can have an outer perimeter portion that is electrically conductive, e.g., metallic. The rear panel 150” can have an electrically conductive frame that extends about at least part of, typically surrounds, the FSS 155. The connecting portion 171 can have a portion that is orthogonal to the main reflector 214 and the primary surface/b ackplane of the rear panel 150”. The rear panel 150” can provide a backplane 150b that is parallel to the main reflector 214, shown as a plane that is behind the main reflector 214. No right and left side reflector strips 170r, 170Z are required. [000140] FIG. 12 shows the seal member 158 inside the rear wall lOOr of the base station antenna housing lOOh. The seal interface surface 154 is also shown inside the rear wall lOOr. An inner wall segment 150i can have a greater lateral extent than an outer wall segment 150o. The reverse orientations can be used with the seal member 158 external to the housing lOOh or with an internal and external seal member (not shown).

[000141] FIGs. 13 and 14 show the rear panel 150” as comprising a dielectric substrate behind the FSS 155.

[000142] FIG. 15 illustrates an example push to connect configuration of the rear panel 150” and the passive antenna assembly 190 inside the base station antenna housing lOOh. The rear panel 150” can be provided as a rear panel assembly 150a with the rear panel 150’ configured to define a power divider circuit 150c coupled to the radiating elements 222 and to a connector 1150. The power divider circuit 150c can be a 1x3 power divider circuit. The connector 1150 can be connected to internal connector 1250 that connects the rear panel assembly 150a to the internal components, e.g., phase shifter 314p and RF connector 140, for example. The connector 1250 can be a coaxial connector.

[000143] FIG. 16 illustrates an enlarged example connector configuration. The connectors 1150, 1250 can be configured as push-pull connector assemblies for allow for ease of installation/assembly but other connector configurations may be used. The connector 1150 can be a surface mounted connector. Typically, there are four feed cable for two columns of (low band) 222 radiating elements.

[000144] 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.

[000145] 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.

[000146] 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 (z.e., "between" versus "directly between", "adjacent" versus "directly adjacent", etc.)

[000147] 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.

[000148] The term “about” used with respect to a number refers to a variation of +/- 10%.

[000149] 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 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. [000150] 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.

Claims

That Which is Claimed is:

1. A base station antenna, comprising: a base station antenna housing comprising a front radome and a rear, wherein the rear comprises an open space that extends longitudinally a sub-length of the base station antenna housing and that extends laterally across at least 50% of a width of the base station antenna housing; a passive antenna assembly in the base station antenna housing; and a rear panel sealably coupled to the rear of the base station antenna housing and positioned to cover the open space, wherein the rear panel comprises a different material than the front radome or comprises a material that is the same but thinner than the front radome.

2. The base station antenna of Claim 1, wherein the rear panel comprises a frequency selective surface (FSS) that is configured to reflect or block electromagnetic waves from radiating elements of the passive antenna assembly and allow higher band electromagnetic waves to travel therethrough toward the front radome.

3. The base station antenna of Claim 2, wherein the FSS is defined by at least one sheet of metal arranged to provide a grid pattern.

4. The base station antenna of Claim 2, wherein the FSS comprises a grid pattern of metal patches.

5. The base station antenna of Claim 2, wherein the FSS comprises a metal pattern of a printed circuit board.

6. The base station antenna of Claim 2, wherein the FSS is attached to a substrate comprising a sheet molding compound or polycarbonate.

7. The base station antenna of Claim 2, wherein a plurality of radiating elements extend forward of the FSS in the base station antenna housing.

8. The base station antenna of Claim 7, wherein the plurality of radiating elements comprise radiating elements configured to transmit and receive signals in at least a portion of the 6167-960 MHz frequency range.

9. The base station antenna of Claim 2, further comprising an active antenna module coupled to the base station antenna housing, wherein the active antenna module comprises an array of radiating elements facing the FSS, and wherein the array of radiating elements of the active antenna module are configured to propagate RF energy through the rear panel.

10. The base station antenna of Claim 9, wherein the array of radiating elements of the active antenna module comprises a mMIMO array of radiating elements positioned behind the rear panel.

11. The base station antenna of Claim 10, wherein a lateral extent of the FSS is a sub-distance of a lateral extent of the base station antenna housing, and wherein the FSS resides at an upper portion of the base station antenna housing, aligned with the array of radiating elements of the active antenna module.

12. The base station antenna of Claim 11, wherein the FSS is configured to allow RF energy to pass through at one or more defined frequency range and reflect RF energy at a different frequency band.

13. The base station antenna of Claim 9, wherein the active antenna module comprises a radome, and wherein the radome of the active antenna module abuts or resides adjacent to and faces the rear panel of the base station antenna housing.

14. The base station antenna of Claim 2, wherein the FSS is configured to reflect RF energy at a low band and pass RF energy at a higher band.

15. The base station antenna of Claim 2, wherein the passive antenna assembly comprises first and second linear arrays that are laterally spaced apart, wherein the rear panel is coupled to a main reflector of the passive antenna assembly, and wherein the FSS defines a backplane and/or reflector for at least some radiating elements of the first and second linear arrays.

16. The base station antenna of Claim 15, wherein the at least some radiating elements are coupled to and project forward of the FSS.

17. The base station antenna of Claim 1, wherein the passive antenna assembly comprises a plurality of linear arrays of radiating elements that extend in front of a reflector.

18. The base station antenna of Claim 1, further comprising an active antenna module coupled to the base station antenna housing with the rear panel in front of the active antenna module.

19. The base station antenna of Claim 1, wherein the rear panel is detachably coupled to the rear of the base station antenna, and wherein a seal member resides between an outer perimeter of the rear panel and the rear of the base station antenna.

20. The base station antenna of Claim 1, wherein the rear panel comprises a sheet molding compound and/or a polycarbonate.

21. The base station antenna of Claim 1, wherein the rear panel comprises an outer perimeter that has rearwardly extending walls surrounding a flat panel extending forward thereof.

22. The base station antenna of Claim 1, wherein the passive antenna assembly comprises a main reflector portion that merges into a pair of laterally spaced apart right and left side reflector strips that face each other across an open space therebetween, and wherein at least a portion of the rear panel extends in front of or behind the open space.

23. The base station antenna of Claim 22, wherein the reflector strips reside in a plane that is behind a plane of the main reflector portion.

24. The base station antenna of Claim 1, wherein the rear panel comprises rearwardly extending sidewalls that extend rearward of a seal interface surface of the rear panel.

25. A base station antenna assembly comprising: a base station antenna housing having a front radome; a plurality of columns of first radiating elements configured for operating in a first operational frequency band inside the base station antenna housing, each column of first radiating elements comprising a plurality of first radiating elements arranged in a longitudinal direction; and a rear panel detachably and sealably coupled to a rear of the base station antenna housing, wherein the rear panel has a lower dielectric constant than the front radome.

26. The base station antenna assembly of Claim 25, wherein the rear of the base station antenna housing comprises an open space extending laterally and longitudinally, wherein the rear panel comprises right and left side walls that extend rearwardly from the base station antenna housing behind right and left side portions of the open space, and wherein the rear panel covers the open space.

27. The base station antenna assembly of Claim 25, wherein the rear panel comprises a frequency selective surface (FSS) that resides behind the plurality of columns of first radiating elements, and wherein the FSS is configured to reflect electromagnetic waves within the first operational frequency band.

28. The base station antenna assembly of Claim 27, further comprising a plurality of columns of second radiating elements configured for operating in a second operational frequency band that is different from and does not overlap with the first operational frequency band, each column of second radiating elements comprising a plurality of second radiating elements arranged in the longitudinal direction, wherein the FSS is further configured such that electromagnetic waves within the second operational frequency band can propagate through the FSS.

29. The base station antenna assembly of Claim 28, wherein the second operational frequency band is higher than the first operational frequency band, and wherein the plurality of columns of second radiating elements are provided by an active antenna module coupled to a rear of the base station antenna housing.

30. The base station antenna assembly of Claim 27, wherein the FSS is defined by a sheet of metal configured with an array of unit cells, and wherein the unit cells have open center spaces devoid of metal that are surrounded by a perimeter of metal.

31. The base station antenna assembly of Claim 27, wherein the FSS is coupled to or provided by a multiple layer printed circuit board and comprises a grid pattern of metal patches.

32. The base station antenna assembly of Claim 27, wherein the rear panel defines a backplane and/or reflector at a common ground with a primary reflector inside the base station antenna housing.

33. The base station antenna assembly of Claim 32, wherein low band radiating elements are supported by the rear panel and project forward of the FSS.