GB2625143A - Antenna support system - Google Patents

Abstract

An antenna support system comprises an intermediate member 202 for securing to a mast, the member having a cross section defining first and second mounting portions (224, Figure 4a), and first and second steering units 236 attached to the first and second mounting portions respectively to provide two spaced-apart steering axes for two respective antennas. The mounting portions preferably define flat, planar surfaces at a non-zero angle to each other. The intermediate member cross section may be an angle section or a box section. The mounting portions may comprise a flange 226 defining cantilevered portions having free ends, and preferably comprises a structural portion which may comprise an angle section, or a circular (Figure 5a) or polygonal (Figure 6a) hollow section. A method of manufacturing an intermediate member for supporting a cellular antenna, comprising extruding the member using an extrusion die, is also provided.

Description

Antenna support system

Technical Field

[0001] The present invention relates to an antenna support system. More specifically, the present invention relates to an antenna support system comprising an intermediate member having mounting formation(s) for the attachment of one or more modern, steerable cellular antennas.

Background Art

[0002] By 'modern' cellular antennas we mean 5G technology and beyond, MIMO and massive-MIMO, multi-band, multi-beam, multi-directional, active or passive antennas.

[0003] Since the early days of mobile communication technology back in the 1990's, directional cellular antennas on towers and masts have been installed using the same principle. The antennas have to be placed high up, away from the ground, in order to reduce the RE path-loss effects (or RE signal attenuation). The antennas also need to point in specific directions in the horizontal plane (i.e., at an azimuth angle about a vertical axis -alignment of the antenna directionality with respect to North) and in the vertical plane (i.e., tilt angle about an horizontal axis-alignment of the antenna directionality with respect to the earth's centre of gravity) in order to satisfy certain RE planning criteria for optimum coverage, capacity and quality of wireless communications.

[0004] To install antennas at a specified height from the ground, mobile communication networks worldwide adopted the engineering and design of very well-known tower and mast types such as lattice and pole systems. The terms 'mast' and 'tower' are often used interchangeably, and it is to be understood that the term "mast" is used in this application to cover both masts and towers. However, it will be noted that in structural engineering terms, a tower is a self-supporting or cantilevered structure, while a mast is held up by stays or guys.

[0005] The self-supported lattice is the most widespread form of construction. It provides high strength, low weight and low wind resistance, and is economic in its use of materials. Lattices of triangular cross-section are most common, and square lattices are also widely used. Guyed lattice masts are also often used; the supporting guy lines carry lateral forces such as wind loads, allowing the mast to be very narrow and of modular construction. The entire structure is constructed by creating a series of horizontal ladders, or internal triangular structures, that secure the tower's three, or four base legs. Guyed masts are also constructed out of steel tubes.

[0006] Last but not least monopole rooftop masts (which may be covered with camouflage and / or a radome) have been installed on top of many buildings. With the advent of urban mobile communications, developers wanted a more efficient way to construct and operate low-height elevation systems for aesthetic reasons. They conceived the idea of the monopole rooftop configuration, a lattice mast with a pole on top used for antenna mounting. These configurations became more fashionable once alternative construction materials began to exhibit greater strength and flexibility without failing. Today these freestanding masts are fabricated from various materials.

[0007] In order to install the antennas on towers and masts at specified directions with respect to North (azimuth alignment) and the earth's centre of gravity (tilt alignment), the industry adopted the engineering and design of antenna azimuth and tilt mounting brackets.

[0008] The legacy antenna tilt bracket is a standard antenna accessory, delivered with the specific antenna purchased, and as such we will not further describe the various types of tilt bracket here. The most common type of antenna azimuth bracket in the field comprises a set of collars that are mounted on one side at the antenna tilt bracket and on the other side are fixed on a pole. Azimuth alignment is performed by loosening the collars, aligning the antenna and tightening the collars on the pole.

[0009] Referring to Figure 1 there is shown such a cellular antenna mast 2 comprising vertical upright members 4 (hollow square section members in this example), horizontal cross-members 6 and bracing members 8. The mast 2 is a square-section lattice mast. For the purposes of the present disclosure, a 'mast member" is a component that is part of the mast. In other words, it is structurally integrated with the mast to the extent that removal would cause structural problems. "Mast members" include monopole rooftop masts installed on buildings, possibly on top of a lattice structure, but not e.g. poles attached to the side of an existing mast (as with legacy systems).

[0010] The support system 10 comprises a pair of pole spacing supports 12, 14. Each support 12, 14 comprises a pair of elongate metal tubes 16, 18 welded on respective ends to mast clamps 30 and pole clamps 20. The mast clamps 30 are attached to the mast (specifically the upright members 4) by clamping. The pole spacing supports 12, 14 are attached to the mast at two spaced-apart vertical positions allowing for a minimum specified spacing of a pole 22 and antenna 24 from the cellular antenna mast 2. The antenna pole 22 is inserted through the pole clamps 20 of both pole spacing supports 12, 14 and clamped therein. The antenna pole 22 defines an antenna azimuth steering axis Z. [0011] Allowing for the required spacing from the mast to be achieved, the pole spacing supports 12, 14 is also configured to allow the riggers to physically install the antenna, and set it at the desired azimuth and tilt direction. Antenna tilt brackets 26,28 are installed each on pole 22. The antenna tilt brackets comprise azimuth collars 27, 29 that clamp the pole 22 and permit selective rotation about the steering axis Z. The collars 27, 29 of the mechanical tilt brackets can be tightened to inhibit antenna rotation about the azimuth steering axis. The mechanical tilt brackets 26,28 also rotate the antenna in the vertical plane (inclination).

[0012] It will be noted that in this example, there are provided pole supports that have two mast clamps and a single pole clamp (i.e. in the shape of a "V"). Other systems are known which may have a single mast clamp and single pole clamp for each pole support.

[0013] In this way, the industry adopted the engineering and design of a universal antenna "support system" that could be installed without implementation problems on both pole and lattice masts while being capable for antenna azimuth and tilt alignment in order to satisfy both the structural engineering requirements and the radio planning instructions.

[0014] However, there are problems with this approach.

[0015] Historically, network operators have also owned and operated masts. Essentially this resulted in one operator per mast. More recently, masts have been owned and operated by specific mast management companies. These companies tend to own the mast asset and lease antenna space to a number of operators. In order to do so, and to realise a return on that investment, the mast management company needs to be able to offer the operator flexibility in the number and azimuth heading of antennas. Inevitably, this results in a potentially crowded mast, with operators often requiring the same azimuth direction for their antennas. This problem is exacerbated with the rise of new technologies utilising cellular data such as 5G and its use in loT. There is an ever growing spatial requirement on masts L0016] There is an inherent limitation with legacy poles 22 from this point of view. Although in theory it is possible to mount-two antennas on the same pole, they will clash if angled too close together. Evidently it is not possible to mount two antennas in the same direction on the pole 22.

[0017] It is an aim of the present invention to provide a further improved solution for the mounting of antennas to masts.

Summary of Invention

[0018] According to a first aspect of the invention there is provided an antenna support system comprising: an intermediate member for securing to a mast, the intermediate member having a cross section defining: a first mounting portion; and, a second mounting portion; a first steering unit; and, a second steering unit; wherein the first steering unit is attached to the first mounting portion, and the second steering unit is attached to the second mounting portion to thereby provide two spaced-apart steering axes for two respective antennas.

[0019] Advantageously, the provision of an intermediate member having two distinct mounting portions each with a dedicated steering unit means that the steering axes can be offset from the intermediate member and each other, in contrast to the prior art in which the single steering axis is aligned with the pole. This in turn means that more than one antenna can be mounted to the intermediate member, with two axes both offset from the intermediate member (and each other), offering a significant advantage over the prior art without alteration to the mast.

[0020] This means that with a two steering axis solution, a prior art mast's capacity can be doubled. For a three steering axis solution it can be tripled. This helps to serve the technical demands of the operators.

L0021] The mast section is non-circular (and non-elliptical). Non-circular and non-elliptical shapes have multiple discrete regions that can be defined as mounting portions. The portions can be separated by corners, or angled portions.

[0022] In one embodiment, the steering units are attached to the respective mounting portions by a friction clamp (i.e., by clamping force). In an alternative embodiment, the mounting portions are provided with mounting formations such as openings through the thickness thereof in order to attach the steering units with mechanical fasteners or other mating members.

[0023] Preferably the mounting portions define flat, planar surfaces at a non-zero angle to each other.

[0024] Preferably the intermediate member cross section is selected from an angle section and a box section.

[0025] Preferably the intermediate member cross-section comprises: [0026] Preferably the structural portion joining the first and second mounting portions. This embodiment is particularly well-suited to the use of mounting formations such as openings through the thickness thereof.

[0027] Preferably the system comprises: a further first steering unit attached to the first mounting portion at a position spaced-apart from and coaxial with the first steering unit; and, a further second steering unit attached to the second mounting portion at a position spaced-apart from and coaxial with the second steering unit; such that: a first antenna can be mounted to the first and further first steering units; and, a second antenna can be mounted to the second and further second steering units.

[0028] Preferably at least one mounting portion comprises at least one cantilevered portion having a free end.

[0029] Preferably the at least one mounting portion comprises two cantilevered portions having oppositely projecting free ends.

[0030] Preferably the at least one mounting portion comprises a flange defining the cantilevered portions, the flange being connected to the structural portion via an arm projecting therefrom, such that the mounting portion is T shaped in profile.

[0031] Preferably the flange is connected to the structural portion via two parallel, offset arms projecting therefrom.

[0032] Preferably the intermediate member has a constant cross section along a primary axis [0033] Preferably the structural portion is a hollow section.

[0034] Preferably the hollow section is circular.

[0035] Preferably the mounting portion extends radially from the hollow section.

[0036] Preferably the hollow section is polygonal.

[0037] Preferably the structural portion is an angle section.

[0038] Preferably the angle section comprises a first leg and a second leg, and wherein the first structural mast member comprises a first mounting portion extending from the first leg and a second mounting portion extending from the second leg.

[0039] Preferably the mounting portions each comprise a plurality of through-bores for the attachment of the first steering unit and the second steering unit.

[0040] Preferably at least some of the through-bores are axially oriented slots to allow for axial adjustment of the steering unit mounted thereto [0041] Preferably a third mounting portion for the attachment of a third antenna is provided.

[0042] According to a second aspect there is provided a method of manufacturing an intermediate member for supporting a cellular antenna, the method comprising the steps of: providing an extrusion die defining an aperture having: a first mounting portion; and, a second mounting portion; extruding an intermediate member using the die; forming openings in the mounting portions; providing a first antenna steering unit and a second antenna steering unit; attaching the first antenna steering unit to the first mounting portion; attaching the second antenna steering unit to the second mounting portion; to thereby provide two spaced-apart steering axes for two respective antennas.

[0043] Preferably the method comprises the steps of: providing a first antenna and a second antenna; mounting the first antenna to the first steering unit; and, mounting the second antenna to the second steering unit.

Brief Description of Drawings

[0044] An embodiment of the present invention will now be described with reference to the following figures in which: FIGURE 1 is a perspective view of a prior art antenna mounting assembly; FIGURE 2 is a perspective view of a cellular antenna mounting assembly comprising a second intermediate member according to the present invention; FIGURE 3 is a detail view of a part of the assembly of Figure 2; FIGURES 4a and 4b are section views of the intermediate member of Figure 2; FIGURES 5a and 5b are section views of a first intermediate member according to the invention; FIGURES 6a and 6b are section views of a third intermediate member according to the invention; and, FIGURES 7a to 7c are perspective views of a fourth intermediate member according to the invention.

Description of the first embodiment

[0045] Referring to Figures 2 to 4b, a first embodiment of the present invention is shown.

Configuration [0046] Referring to Figure 2, there is shown a cellular antenna assembly 200. The assembly 200 comprises an intermediate member 202, first and second antenna mounting assemblies 204, 206 and two antennas 212, 214.

[0047] The intermediate member 202 is shown in more detail in Figures 3 and 4. It is an extruded component and is therefore prismatic along a primary axis A having a cross-section profile in a section plane SP normal to axis A. [0048] Referring to Figure 4, the cross-section profile of the mast member 202 has a structural portion 220 which is a 90-degree angle section having first and second limbs 220a, 220b. Two mounting formations extend from respective limbs of the structural portion. By way of example, a first mounting formation 224 comprises a first arm 224a and a second arm 224b which are offset and parallel, each joining the limb 220a at spaced apart positions. The arms 224a, 224b terminate in a mounting flange 226 which is normal to the arms 224a, 224b such that part of the structural portion 220, the arms 224b, 224b and the flange 226 form an enclosed section enclosing a void 228. The flange 226 extends past either side of each arm to define a central portion 230 and two overhanging edge portions 232a, 232b. Referring to Figure 6, the flange 226 defines through thickness openings 234 in the edge portions 232a, 232b.

[0049] The mounting formations are at 90 degrees to each other and are unitary (co-extruded) with the structural portion.

[0050] Referring to Figure 5, the antenna mounting assemblies 204, 206 each comprises at least two steering units 236 spaced-apart along the axis A. Each steering unit comprises a mast mounting portion 238, an antenna mounting portion 240 and a rotational joint 242 allowing the portions 238, 240 to be rotated about a steering axis SA. The steering units used in the present invention are the same as those described in applicant's previous application WO 2021/074335.

[0051] The mast mounting portions 236 each comprising a flange 242 having a plurality of openings 244. The steering units 236 can thereby be mounted to the radially outwardly facing surface of each flange 226. Each of the steering units 236 mounted to a single flange 226 is aligned such that the steering axis SA are aligned.

[0052] Attached to each of the assemblies 204, 206, there is provided a respective antenna 212, 214. The antennas are generally elongate and mounted parallel to the axis A. They are mounted to the respective antenna mounting portions 240 of each pair of steering units 236. In this way, the antennas can each be steered about the steering axis SA.

[0053] It will be noted that for the antenna mounting assembly 210 in Figure 3, a spacer 246 is provided to increase the distance between the main axis A and the steering axis SA. This is an optional feature.

[0054] In use, the assembly 200 can be used in place of the pipe 22, antenna 24 and associated equipment in Figure 1. Referring to Figure 4b, an intermediate member clamp 250 is shown. The clamp 250 comprises a first part 250a and a second part 250b. The first part 250a is attached to legs 252a, 252b which, like the legacy system, are attached to the mast 2. The clamp 250 is shown schematically-the important point is that it (and another clamp, located along the intermediate member axis) are capable of supporting the intermediate member, antenna and associated parts.

[0055] It will be noted that in Figure 4b, antennas would be positioned with steering axes AX1, AX2 to one side and tothe front of the member 202 respectively (note that the steering units are not shown in Figure 4b). The member 202 may be rotated in use through increments of 90 degrees, for example to position AX2 to the opposite side of AX1, and AX1 in front of the mast.

Description of the second embodiment

[0056] Referring to Figures 5a and 5b, there is shown an intermediate member 102. It is an extruded component and is therefore prismatic along a primary axis A having a cross section profile in a section plane SP normal to axis A. The member 102 is elongate, by which we mean it has an axial length which is at least 5 times its largest dimension in cross-section.

L0057] Referring to Figure 5a, the cross-section profile of the member 102 has a central structural portion 120 which is a closed, circular shape. Four identical, equally spaced mounting formations extend from the structural portion. By way of example, a first mounting formation 122 comprises a first arm 124a and a second arm 124b which are offset and parallel, each joining the structural portion 120 at spaced apart positions. The arms 124a, 124b terminate in a mounting flange 126 which is normal to the arms 124a, 124b such that part of the structural portion 120, the arms 124b, 124b and the flange 126 form an enclosed section enclosing a void 128. The flange 126 extends past either side of each arm to define a central portion 130 and two overhanging edge portions 132a, 132b. The flange 126 may define through thickness openings in the edge portions for attachment of the steering units.

[0058] The mounting formations are equally spaced at 90 degrees to each other and are unitary (co-extruded) with the structural portion.

[0059] In use, the member 102 can be used in place of the pipe 22, antenna 24 and associated equipment in Figure 1. Referring to Figure 5b, an intermediate member clamp 250 is shown. The clamp 150 comprises a first part 150a and a second part 150b. The first part 150a is attached to legs 152a, 152b which, like the legacy system, are attached to the mast 2. The clamp 150 is shown schematically-the important point is that it (and another clamp, located along the intermediate member axis) are capable of supporting the intermediate member, antenna and associated parts.

Description of the third embodiment

[0060] Referring to Figures 6a and 6b, a third embodiment of the present invention is shown.

Configuration [0061] Referring to Figures 6a and 6b, there is shown an intermediate member 302. It is an extruded component and is therefore prismatic along a primary axis A having a cross-section profile in a section plane SP normal to axis A [0062] Referring to Figure 6a, the cross-section profile of the mast member 302 has a structural portion 320 which is a hollow rectangular section having first and second long sides 320a, 320b and first and second short sides 321a, 321b. Two mounting formations extend from respective ends of the structural portion. A first mounting formation 324 comprises a first mounting flange 324a and a second mounting flange 324b which parallel and continuous with the short side 321a and overhang. Referring to Figure 9, the flanges 324a, 324b define through thickness openings 334.

[0063] In use, the member 302 can be used in place of the pipe 22, antenna 24 and associated equipment in Figure 1. Referring to Figure 6b, an intermediate member clamp 350 is shown. The clamp 350 comprises a first part 350a and a second part 350b. The first part 350a is attached to legs 352a, 352b which, like the legacy system, are attached to the mast 2. The clamp 350 is shown schematically-the important point is that it (and another clamp, located along the intermediate member axis) are capable of supporting the intermediate member, antenna and associated parts.

[0064] It will be noted that in Figure 6b, antennas would be positioned with steering axes AX1, AX2 to either side of the member 202 respectively (note that the steering units are not shown in Figure 6b). The member 202 may be rotated in use through increments of 90 degrees, for example to position a single antenna with steering axis AX1 in front of the mast

Description of the fourth embodiment

[0065] Referring to Figures 6a to 7c, a third embodiment of the present invention is shown. Configuration [0066] An intermediate member 402 is shown. It is an extruded component and is therefore prismatic along a primary axis A having a cross-section profile in a section plane SP normal to axis A. [0067] Referring to Figure 6a, the cross-section profile of the mast member 402 has an integrated structural / mounting portion 420 which is an angle section having first and second limbs 420a, 420b. Each limb, as well as providing structural rigidity, serves as a mounting formation. The limbs 420a, 420b define through thickness openings 422 at a first mounting location, and through thickness openings 424 in the form of axial slots at a second mounting location.

[0068] In use, the member 402 is used in place of the pipe 22, antenna 24 and associated equipment in Figure 1. An intermediate member clamp is not shown, but would be used per the previous embodiments to mount the member to a mast.

L0069] Two spaced-apart but aligned azimuth steering and locking units 500a, 502a are mounted on the first limb 420a, and two spaced-apart but aligned azimuth steering and locking units 500b, 502b are mounted on the second limb 420b.

[0070] The lower units 502a, 502b can be moved in an axial sense during installation by sliding them up and down the openings 424. This allows for the distance between the units 500a, 502a; 500b, 502b to be adjusted to accommodate different sizes (heights) of antennas [0071] The first units 500a, 502a define a first steering axis AZ1 about which an antenna 504a can be rotated relative to the intermediate member 420. The second units 500b, 502b define a second steering axis AX2 about which an antenna 504b can be rotated relative to the intermediate member 420.

[0072] It is noted that because the axes AX1, AX2 are spaced apart, two antennas may be mounted to the mast at the same height, and may be configured to be directed in the same or a similar / overlapping direction. This provides increased functionality and in addition avoids the need for additional componentry at the tower top, which would otherwise increase mass and wind loading on the mast.

Variations [0073] As well as being constructed from extruded aluminium, the mast members according to the invention may be constructed from other extruded materials, such as composites.

[0074] The above embodiments provide for two steering units spaced along the member. Different numbers of units may be provided for different sized antennas. Small antennas may only require one such unit, larger antennas may require three or more. It is within the scope of the present invention to provide a single, or multiple steering units supporting a single antenna.

Claims (1)

1. Claims 1. An antenna support system comprising: an intermediate member for securing to a mast, the intermediate member having a cross section defining: a first mounting portion; and, a second mounting portion; a first steering unit. and, a second steering unit; wherein the first steering unit is attached to the first mounting portion, and the second steering unit is attached to the second mounting portion to thereby provide two spaced-apart steering axes for two respective antennas 2. An antenna support system according to claim 1, wherein the steering units are attached to the respective mounting portions by a friction clamps.3 An antenna support system according to claim 1, wherein the mounting portions are provided with mounting formations such as openings through the thickness thereof, and the steering units are attached with mating members.4. An antenna support system according to any preceding claim, wherein the mounting portions define flat, planar surfaces at a non-zero angle to each other.5. An antenna support system according to claim 4, wherein the intermediate member cross section is selected from an angle section and a box section.6. An antenna support system according to any preceding claim, wherein the intermediate member cross-section comprises: a structural portion integral with the first and second mounting portions, the structural portion joining the first and second mounting portions.An antenna support system according to any preceding claim, comprising: a further first steering unit attached to the first mounting portion at a position spaced-apart from and coaxial with the first steering unit; and, a further second steering unit attached to the second mounting portion at a position spaced-apart from and coaxial with the second steering unit; such that: a first antenna can be mounted to the first and further first steering units; and, a second antenna can be mounted to the second and further second steering units.8. An antenna support system according to any preceding claim, wherein at least one mounting portion comprises at least one cantilevered portion having a free end.9. An antenna support system according to claim 8, wherein the at least one mounting portion comprises two cantilevered portions having oppositely projecting free ends.10. An antenna support system according to claim 10 dependent on claim 6, wherein the at least one mounting portion comprises a flange defining the cantilevered portions, the flange being connected to the structural portion via an arm projecting therefrom, such that the mounting portion is T shaped in profile.11. An antenna support system according to claim 8, wherein the flange is connected to the structural portion via two parallel, offset arms projecting therefrom.12. An antenna support system according to any preceding claim, wherein the intermediate member has a constant cross section along a primary axis.13. An antenna support system according to claim 6 or any claim dependent thereon, wherein the structural portion is a hollow section.14. An antenna support system according to claim 13, wherein the hollow section is circular.15. An antenna support system according to claim 14, wherein the mounting portion extends radially from the hollow section.16. An antenna support system according to claim 13, wherein the hollow section is polygonal.17. An antenna support system according to any of claims 13 to 16, wherein the structural portion is an angle section.18. An antenna support system according to claim 13, wherein the angle section comprises a first leg and a second leg, and wherein the first structural mast member comprises a first mounting portion extending from the first leg and a second mounting portion extending from the second leg.19. An antenna support system according to claim 3, wherein at least some of the mounting formations are axially oriented slots to allow for axial adjustment of the steering unit mounted thereto.20. An antenna support system according to any preceding claim, comprising a third mounting portion for the attachment of a third antenna.21. A method of manufacturing an intermediate member for supporting a cellular antenna, the method comprising the steps of: providing an extrusion die defining an aperture having: a first mounting portion; and, a second mounting portion; extruding an intermediate member using the die; forming openings in the mounting portions; providing a first antenna steering unit and a second antenna steering unit; attaching the first antenna steering unit to the first mounting portion; attaching the second antenna steering unit to the second mounting portion; to thereby provide two spaced-apart steering axes for two respective antennas..22. A method of manufacturing according to claim 21, comprising the step of: providing a first antenna and a second antenna; mounting the first antenna to the first steering unit; and, mounting the second antenna to the second steering unit.