WO2016009295A1

WO2016009295A1 - Collapsible antenna of unitary construction

Info

Publication number: WO2016009295A1
Application number: PCT/IB2015/054956
Authority: WO
Inventors: Andries Petrus Cronje Fourie; Eduard Walker; Mark Pierre HAARHOFF; Derek Colin NITCH
Original assignee: Poynting Antennas (Pty) Limited
Priority date: 2014-07-17
Filing date: 2015-07-01
Publication date: 2016-01-21
Also published as: MX2016016728A

Abstract

An antenna 10 of unitary construction comprises a spine 12 and at least first and second pairs 14,16 of radiating elements. Each radiating element comprises a proximate end 20 permanently connected to the spine and a distal end 22. Each radiating element 14.1 comprises a first part 14.11 adjacent the proximate end and a second part 14.12 permanently hinged to the first part. The antenna is manipulatable between a collapsed configuration and an operative configuration. In the collapsed configuration, the first and second parts are in a collapsed configuration and the proximate ends are in a collapsed configuration relative to the spine. In the operative configuration, the first and second parts are extended and the proximate ends are in an operative configuration relative to the spine, so that the first pair of radiating elements are located in a first plane and the second pair of radiating elements are located in a second and different plane.

Description

COLLAPSIBLE ANTENNA OF UNITARY CONSTRUCTION

INTRODUCTION AND BACKGROUND

This invention relates to an antenna. More particularly, this invention relates to a broadband antenna that could be packed in at least a partially collapsed configuration for easy storage or transportation and then conveniently be deployed or manipulated to an operative configuration at a user site or premises.

One application for broadband antennas covering a frequency band extending between about 470MHz and about 840 MHz, is for receiving television broadcasts at a user premises or site. Two currently known antennas for this purpose are a log periodic antenna and bowtie with grid reflector antenna. Aesthetically, the grid may not be acceptable for some applications and/or customers. The antennas are also generally bulky. This is particularly a disadvantage for storage and transportation purposes as the antenna takes up unnecessary space resulting in wasted costs. It is also generally required for a skilled person to correctly deploy and install these known antennas.

OBJECT OF THE INVENTION

Accordingly, it is an object of the present invention to provide an antenna with which the applicant believes the aforementioned disadvantages may at least be alleviated or which may provide a useful alternative for the known antennas. SUMMARY OF THE INVENTION

According to the invention there is provided an antenna of unitary construction comprising a spine and at least first and second pairs of radiating elements, each radiating element comprising a proximate or feed end permanently connected to the spine and a distal end, each radiating element comprising at least a first part adjacent the proximate end and a second part adjacent the distal end, the first and second parts are permanently connected to one another in a movable manner, the antenna being manipulatable between a collapsed configuration and an operative configuration, in the collapsed configuration of the antenna the at least first and second parts of each radiating element being in a collapsed configuration relative to one another and the proximate ends of the radiating elements being in a first collapsed configuration relative to the spine and in the operative configuration of the antenna, the at least first and second parts of each radiating element being extended to an operative configuration relative to one another and the proximate ends of the radiating elements being in an operative configuration relative to the spine, so that the first pair of radiating elements are located in a first plane and the second pair of radiating elements are located in a second and different plane.

It is well known that antennas are reciprocal devices which may be used for either transmitting signals or receiving signals or both. It will hence be appreciated that when in this specification any term is used in one context, for example in a transmitting context, where appropriate the term must be construed to include the term in the reciprocal context of receiving.

The spine may comprise first and second parts on either side of a main axis of the spine, the proximate ends of the first radiating element of the at least first pair and second pair of radiating elements may be pivotably connected to the first part of the spine to pivot about respective axes which are orthogonal to the main axis of the spine and the proximate ends of the second radiating element of the at least first pair and second pair of radiating elements may be pivotably connected to the second part the spine to pivot about respective axes which are orthogonal to the main axis, the axes of the first and second elements of any pair being axially in line.

The proximate end of each radiating element may comprise a respective head comprising a first face and an opposite second face, the second face may be in flush mechanical and electrical contact with the spine and the first face may cooperate with biasing means for biasing the second face into mechanical contact with the spine.

The head may further comprise opposed sides sloping from respective cheeks towards a crown at the proximate end of the radiating element. The antenna may comprise three pairs of radiating elements, so that in the operative configuration of the antenna, the third pair of radiating elements are located in a third plane which is different from the first and second planes.

The head of the first radiating element of each pair may be provided in juxtaposition on the first part of the spine and the head of the second radiating element of each pair may be provided in juxtaposition on the second part of the spine and the arrangement may be such that in the operative configuration of the antenna, the sloping sides of adjacent heads abut against one another to cause the radiating elements to be located in the respective first, second and third planes which diverge from one another in a direction away from the spine. The spine may comprise biasing means for biasing the juxtaposed heads towards the operative configuration. The biasing means may comprise a suitable spring.

In one embodiment, the spring may be a W-shaped spring with mutually converging limbs towards a centre of the spring engaging in a notch of the crown of a centre one of the juxtaposed heads and outer limbs of the spring engaging outer sides of outer heads of the juxtaposed arrangement thereby to bias the sloping sides of adjacent heads into abutting relationship with one another, to cause the radiating elements to be located in the diverging planes.

The first and second parts of each radiating element may be pivotably connected to one another in a junction region. The junction region may comprise a pivot enabling the second part to pivot about a pivotal axis relative to the first part.

The at least one of the first part and the second part may comprise an engagement formation for cooperating with a cooperating formation on the other part to lock the first and second parts in the operative or extended configuration relative to one another. The junction region may further comprise biasing means for maintaining said cooperating formations in cooperating relationship. The biasing means may be configured for exerting a force axially in line with the pivotal axis. The biasing means may comprise a spring.

The radiating elements of each pair may be curved. More particularly, each of the first part and second part of a radiating element may be curved and the respective curvatures may be such that when the first and second parts are in the extended or operative configuration, they collectively form a continuous curvature. In the operative configuration, the radiating elements of each of the at least first pair of radiating elements and second pair of radiating elements may be elongate and curved. In the operative configuration of the antenna, each pair of radiating elements, towards their distal ends, extend in diverging relationship relative to one another such that at points on a centre line between the first and second radiating elements, a ratio (b/a) of a transverse distance b between the first and second radiating elements through the point and a distance a from the feed ends to the point, increases. The ratio may increase in a non-linear manner. In some embodiments, the ratio may increase exponentially.

The invention also includes within its scope a radiating element as herein defined and/or described and a pair of radiating elements as herein defined and/or described.

BRIEF DESCRIPTION OF THE ACCOMPANYING DIAGRAMS

The invention will now further be described, by way of example only, with reference to the accompanying diagrams wherein:

figure 1 is a perspective view of an example embodiment of an antenna in a fully collapsed configuration;

figure 2 is a similar view with the antenna in a partially collapsed configuration; figure 3 is a similar view with the antenna in an operative configuration;

figure 4 is a view similar to that of figure 3 illustrating three different planes in which three pairs of radiating elements of the antenna are located in the operative configuration;

figure 5 is a side view of the antenna illustrating the radiating elements of a pair of radiating elements diverging away from one another;

figure 6 is an enlarged view of a first part of a spine of the antenna and proximate ends of radiating elements connected to the spine showing their relative configuration when the antenna is in the collapsed configuration;

figure 7 is a similar view, but when the antenna is in the operative configuration;

figure 8 is a similar view illustrating a) in broken lines the relative configuration when the antenna is in the collapsed configuration of figure 6 and b) in solid lines the relative configuration when the antenna is in the operative configuration of figure 7;

figure 9 is an enlarged view of a junction between adjacent first and second parts of a radiating element with the first and second parts in a collapsed configuration relative to one another; figure 10 is a similar view, but with the first and second parts in an extended or operative configuration.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

An antenna of unitary construction is generally designated by the reference numeral 10 in figures 1 to 5. The antenna is manipulatable between a collapsed configuration shown in figure 1 and an operative configuration as shown in figure 3.

Referring firstly to figures 3 to 5, the antenna comprises a spine 12 comprising first and second similar parts 12.1 and 12.2 (best shown in figure 5) on either side of a main axis 13. The antenna further comprises at least a first pair 14 and a second pair 16 of elongate, preferably curved, radiating elements. In figures 3 to 5, there is also shown a third pair 18. Any suitable number of pairs may be provided. Except as indicated below, the pairs are substantially similar and therefore only the first pair 14 will now be described in more detail below. First pair 14 comprises a first radiating element 14.1 and a second radiating element 14.2. Also, except as indicated below, the radiating elements of a pair are similar and therefore only radiating element 14.1 will be described in more detail blow.

First radiating element 14.1 comprises a proximate or feed end 20 which is permanently, but movably connected to the spine 12 and a distal end 22. The proximate end 20 is preferably pivotably connected at 24 to the spine to pivot about an axis 26 which is orthogonal to main axis 13. The distal end is preferably free.

First radiating element 14.1 comprises at least a first elongate curved part

14.1 1 adjacent the proximate end 20 and a second elongate curved part

14.12 adjacent the distal end 22. The parts are permanently connected to one another in a movable manner in a junction region 28, best shown in figures 9 and 10. The junction region may comprise a pivot or hinge 30 to enable manipulation of the first and second parts 14.11 and 14.12 from a collapsed configuration relative to one another as shown in figures 1 , 2 and 9 to an extended or operative configuration as shown in figures 3 to 5 and 10. It will be appreciated that radiating element 14.1 may comprise any suitable number of similarly connected parts.

As best shown in figure 5, the first and second radiating elements 14.1 and 14.2 of each of the at least first pair 14 and the second pair 16 have their respective proximate feed ends in juxtaposition relative to one another on either side of an axis 32 (which is orthogonal to the above main axis 13) and extend in diverging relationship away from one another in a direction from their respective proximate ends towards their respective distal ends. The at least first pair 14 and second pair 16 are electrically connected in parallel. As shown in figure 4, the first pair 14 of radiating elements are located in a first plane 31 , the second pair 16 of radiating elements are located in a second plane 33 and the third pair 18 of radiating elements are located in a third plane 34. The first plane 31 , the second plane 33 and the third plane 34 are diverging away from one another from a common origin at about the spine 2 in a direction away from the spine.

As best shown in figure 5 and with reference to first pair 14 only, the radiating elements 14.1 and 14.2 of each pair, towards their distal ends, extend in diverging relationship from one another such that at points on axis 32 between the radiating elements, a ratio (b/a) of a transverse distance b between the elements of a pair through the point and a distance a from the spine or feed ends to the point increases non-linearly in an axial direction away from the spine. Preferably, the ratio increases exponentially.

As is illustrated in figure 3, the transverse cross section of each element is less towards the distal end 22 thereof than towards the feed end 20 thereof. The transverse cross section may decrease from the feed end 20 continuously towards the distal end 22. The radiating elements are made from any suitable conductive material, such as aluminium and may be cast or moulded from a suitable aluminium alloy.

Referring to the enlarged view in figure 6, proximate or feed end 20 of first radiating element 14.1 of the first pair and the corresponding proximate or feed ends 40 and 42 of first radiating elements 16.1 and 18.1 (of the second and third pairs respectively) form a juxtaposed arrangement substantially on a line parallel with main axis 13 on first part 12.1 of spine 12. It will be appreciated that the ends 40 and 42 are also pivotable about respective axes parallel to axis 26. The proximate ends of the radiating elements 14.1 , 16.1 and 18.1 each comprises a respective head 50 which is similar and therefore the head 50 of radiating element 14.1 only will be described.

The head 50 comprises a generally flat first face 52 and opposed second face (not shown). The second face is in flush mechanical and electrical contact with a flat surface 54 of spine part 12.1. The first face 52 cooperates with a first spring 56 to bias the head axially in line with axis 26 into the mechanical and electrical contact with surface 54. The head further comprises opposed sides 58 and 60 sloping from a respective cheek 61 towards one another in a direction towards a crown 62. The crown 62 comprises a V-shaped notch 64. Second biasing means in the form of a suitable spring, in the example embodiment a generally W-shaped spring 66, is mounted on spine part 12.1. Converging limbs 68, 70 towards a centre of the spring extend into and engage with notch 64 of centre radiating element 16.1 of the juxtaposed arrangement of heads at proximate ends of the radiating elements 14.1 , 16.1 and 18.1 . A limb 72 of the spring towards one end of the spring engages side 58 of the head of outer radiating element 14.1 at one end of the juxtaposed arrangement while a limb 74 of the spring towards an opposite end of the spring engages with side 60 of the outer radiating element 18.1 at the opposite end of the juxtaposed arrangement.

The spring is configured to exert a compressing force between limbs 72 and 74 thereof.

It will be appreciated that the proximate ends of second radiating elements 14.2, 16.2 and 18.2 are similarly provided on a corresponding opposing surface of spine part 12.2, with the respective pivotal axes of the radiating elements of a pair axially in line. That is, the axis 26 of radiating element 14.1 is axially in line with the corresponding axis of the other radiating element 14.2 of the pair 14 and the same applies for the radiating elements of the pair 16 and the radiating elements of the pair 18. The pivotal axes of the pairs are parallel to one another. Referring to figure 1 which illustrates the antenna in the fully collapsed configuration, when a packaging constraint such as strap 80 shown in figure 1 is applied to the first parts 14.11 , 14.21 , 16.11 , 16.21 , 18.11 , 18.21 of the elements of the pairs 14, 16 and 18, the proximal ends of the radiating elements are in the positions shown in figure 6 and in broken lines in figure 8 and the cheeks 61 of the heads 50 abutting against one another.

When the constraint 80 is removed, the spring 66 urges the proximate ends 20, 40, 42 automatically to pivot about axes 26 and to adopt the configuration shown in figure 7 and in solid lines in figure 8. That is, with the side 60 of the head of outer radiating element 14.1 abutting against the side 58 of the head of centre element 16.1 and the side 60 of the head of other outer element 18.1 abutting against the side 58 of the head of centre element 16.1.

In figures 9 and 10 the aforementioned junction region 28 between the first part 14.11 and the second part 14.12 of radiating element 14.1 is shown in more detail. Hinge or pivot 30 enables the second part 14.12 to be pivoted in an clockwise manner from the collapsed configuration relative to the first part 14.11 shown in figures 1 , 2 and 9 to an extended or operative configuration shown in figures 3 to 5 and 10. Suitable stopper and/or engagement formations 90, 92 are provided on at least one of the first and second members to lock and maintain the first and second parts in the required continuous curved relationship with one another. A third spring 94 exerts a biasing force to retain the formations 90 and 92 in proper engaging relationship.

Hence, when the constraint 80 in figure 1 is removed, the first parts 14.1 1 , 14.21 , 16.1 1 , 16.21 , 18.1 1 , 18.21 automatically, and under bias of the W- shaped spring 66 adopt the configuration as shown in figures 2 and 7 and in solid lines in figure 8. Thereafter the second parts 14.12, 14.22, 16.12, 16.22, 18.12, 18.22 may be manually pivoted to their extended positions as shown in figures 3 to 5 and 10 thereby to manipulate the antenna into its operative configuration as depicted in figures 3 to 5.

The antenna 10 does not comprise a ground plane and the radiating elements of a pair are driven out of phase. All radiating elements may be identical. The elements of a pair start at the feed end parallel to or at a small angle relative to each other in a transmission line mode and diverge to a radiating mode. All pairs are active in equal part at all frequencies and rely on the "Vivaldi" shape which in a broadband manner enables each pair to transform a transmission line mode to radiating wave over a broad frequency band. Hence, each pair comprise two radiating elements which are fed in opposite phase such that the feed ends commence with radiators electrically close together and with equal and opposite currents "transmission line region" and where the radiators start diverging from each other such that the distal ends are separated by a distance which is large in terms of wavelength (ideally around half a wavelength, but at least quarter of a wavelength at the lowest frequency of operation) forming a "radiating region". The diverging curve with distance from the feed in the direction along the axis 32 between the two elements can be manipulated to achieve broad band matching and directivity properties for the antenna.

The addition of more pairs of the above type and their angle and juxtaposition relative to the other elements could be optimised to further increase antenna directivity and or matching characteristics. It will be appreciated that there are many variations on the antenna as herein defined and/or described without departing from the scope and spirit of this disclosure. In some embodiments it is preferred that the antenna may once only be manipulated from the collapsed configuration to the operational configuration and any effort thereafter to collapse it again, may result in damage to the antenna.

Claims

1. An antenna of unitary construction comprising a spine and at least first and second pairs of radiating elements, each radiating element comprising a proximate or feed end permanently and moveably connected to the spine and a distal end, each radiating element comprising at least a first part adjacent the proximate end and a second part adjacent the distal end, the first and second parts are permanently connected to one another in a movable manner, the antenna being manipulatable between a collapsed configuration and an operative configuration, in the collapsed configuration of the antenna the at least first and second parts of each radiating element being in a collapsed configuration relative to one another and the proximate ends of the radiating elements being in a first collapsed configuration relative to the spine and in the operative configuration of the antenna, the at least first and second parts of each radiating element being extended to an operative configuration relative to one another and the proximate ends of the radiating elements being in an operative configuration relative to the spine, so that the first pair of radiating elements are located in a first plane and the second pair of radiating elements are located in a second and different plane.

The antenna as claimed in claim 1 wherein the spine comprises first and second parts on either side of a main axis of the spine, the proximate ends of the first radiating element of the first pair and second pair of radiating elements being movably connected to the first part of the spine in pivotal manner about respective pivotal axes which are orthogonal to the main axis of the spine and the proximate ends of the second radiating element of the first pair and second pair of radiating elements are movably connected to the second part of the spine in pivotal manner about respective pivotal axes which are orthogonal to the main axis, the pivotal axes of the first and second elements of the first and second pairs respectively being axially in line.

The antenna as claimed in any one of claims 1 and 2 wherein the proximate end of each radiating element comprises a respective head comprising a first face and an opposite second face, the second face being in mechanical and electrical contact with the spine and the first face cooperating with first biasing means for biasing the second face into the mechanical and electrical contact with the spine.

4. The antenna as claimed in claim 3 wherein the head further comprises opposed sides sloping from respective cheeks towards a crown at the proximate end of the radiating element.

5. The antenna according to any one of the previous claims wherein the antenna comprises three pairs of radiating elements and wherein, in the operative configuration of the antenna, the third pair of radiating elements are located in a third plane which is different from the first and second planes.

6. The antenna as claimed in claim 5 wherein the heads of the first radiating element of each pair is provided in juxtaposition on the first part of the spine and the heads of the second radiating element of each pair is provided in juxtaposition on the second part of the spine, so that in the operative configuration of the antenna, the sloping sides of adjacent heads abut against one another to cause the radiating elements to be located in the respective first, second and third planes which diverge from each another in a direction away from the spine.

7. The antenna as claimed in claim 6 wherein the spine comprises second biasing means for biasing the juxtaposed heads towards the operative configuration.

8. The antenna as claimed in claim 7 wherein the second biasing means comprises a W-shaped spring with mutually converging limbs towards a centre of the spring engaging in a notch of the crown of a centre one of the juxtaposed heads and outer limbs of the spring engaging outer sides of outer heads of the juxtaposed arrangement thereby to bias the sloping sides of adjacent heads into abutting relationship with one another, to cause the radiating elements to be located in the diverging planes.

9. The antenna as claimed in any one of claims 1 to 9 wherein the first and second parts of each radiating element are pivotably connected to one another in a junction region defining a pivotal axis.

10. The antenna as claimed in claim 9 wherein the at least one of the first part and the second part comprises an engagement formation for cooperating with a cooperating formation on the other of the first part and second part to lock the first and second parts in the operative or extended configuration relative to one another.

11. An antenna as claimed in claim 10 wherein the junction region comprises a third biasing means for maintaining the cooperating formations in a cooperating relationship.

12. The antenna as claimed in claim 11 wherein the third biasing means is configured for exerting a biasing force axially in line with the pivotal axis.

13. The antenna as claimed in any one of claims 1 to 12 wherein each of the first part and second part of the radiating element are curved and the respective curvatures are such that when the first and second parts are in the extended or operative configuration, they collectively form a continuous curvature.

14. The antenna as claimed in claim 13 wherein, in the operative configuration of the antenna, the radiating elements of each pair of radiating elements towards their distal ends extend in diverging relationship relative to one another such that at points on a centre line between the first and second radiating elements, a ratio (b/a) of a transverse distance b between the first and second radiating elements through the point and a distance a from the proximate ends to the point, increases.

15. A radiating element comprising

at least a first curved part and a second curved part;

the first and second curved parts being permanently hinged to one another, so that the radiating element is manipulatable between a collapsed configuration and an operative configuration wherein the first and second parts collectively form a continuous curvature.