WO2007032690A1

WO2007032690A1 - Broadband antennas

Info

Publication number: WO2007032690A1
Application number: PCT/NZ2006/000238
Authority: WO
Inventors: Gregory D Hall
Original assignee: Gregory D Hall
Priority date: 2005-09-13
Filing date: 2006-09-13
Publication date: 2007-03-22

Abstract

Discloses preferred methods of connecting plate dipole elements within an antenna and of combining these plate elements with other dipoles elements for optimal results. Methods of achieving dual polarisation in a single antenna are disclosed. An antenna comprising a single plate is disclosed.

Description

BROADBAND ANTENNAS

FIELD OF INVENTION

The invention relates to field of broadband antennas. Examples of such antennas are Combined VHF/UHF/FM receivers/transceivers.

INTRODUCTION

For most known antenna designs the dipole elements are formed to specific lengths to resonate to specific frequencies. Key measurements within the dipole are harmonics (eg 1, ¹A, 1/3, VA) of specific frequency wavelength(s). Such dipoles perform acceptably for frequencies close or harmonically related to the frequencies for which they are designed. However, these dipoles perform less acceptably, if at all, for other non-harmonically related frequencies. Moreover, the dipole must be aligned with the signal polarity to perform satisfactorily.

Plate dipole antennas were first described by this inventor (see Patent: NZ 504042, WO-Ol- 80364-1). This document describes variations and refinements with the use of plate dipole elements beyond the scope of the above-mentioned patents. In particular, this document discloses preferred methods of connecting plate dipole elements within an antenna and of combining these plate elements with other dipoles elements for optimal results. Methods of achieving dual polarisation in a single antenna are disclosed. An antenna comprising a single plate is disclosed.

SPECIFICATION

DEFINITIONS

The following terms are defined for the purposes of this document, provided however that ordinary meanings as understood by someone skilled in antenna design are not excluded where they are not inconsistent with a definition given below:

Attachment means the direct electrical connection of a conductive element in a manner that substantially defines a continuation of the surface of the plate element. For clarity where a secondary element is substantially separated from the plate element it is not regarded as an attachment even though it is directly electrically connected via a feedline/phase connector. Where a conductive element is a continuation of the shape and surface of a plate element but may have been designed as a separate piece for manufacturing, packaging or assembly purposes then the combined pieces are regarded as a single plate element not as plate and attachment.

Bowtie refers to the dipole elements making up a bowtie dipole antenna. These antennas include substantially triangular half bowtie pieces that would meet near the middle in a manner that resembles a bowtie tie shape. Bowtie dipole elements are generally a skeleton but may be solid or mesh. Multiple bowtie elements may be arranged about a common centre, perhaps arranged on a cone or pyramid.

Cable means the antenna connection to a receiver, transmitter and /or transceiver. It includes configurations where in fact no cable is present such as where the radio set is integrated with the antenna.

Corner Zone means that area within a radius equivalent to 33% of the Plate Width from the corner of a plate dipole element and for cable connection purposes further includes any Attachments connected via the corner zone. Where the corner of a plate is rounded or clipped the Corner Zone is measured from where the comer would be were the plate element rectangular.

Discontinuity means holes in the plate surface; areas where the conductive plate surface is not continuous.

Edge Zone means that area within 20% of the Plate Width measured from either side or end of the plate element and for cable connection purposes further includes any Attachments connected via the edge zone.

Electi'ically connected means able to conduct an electric signal. It includes feedline connection, inductive coupling and coupling through electrical devices such as a balun, multiplexer, amplifier or frequency transposer.

Feedline means a conductive connection to dipole elements carrying a single polarity.

Isolated means there is no direct electrical connection. In the context of paired dipole elements, these are said to be isolated when there is no conductivity between the elements except perhaps ultimately through an electrical device such as a balun, multiplexer, amplifier or transmitter and/or receiving set.

Not Overlapping means that with plate elements of a pair if the plate element enclosed surface area is projected perpendicular to the primary plane of that element for a distance equivalent to the plate element length, such projection will not intersect with a plate element with an opposite polarity. Where there is no identifiable primary plane such as with an even curvature the perpendicular projection of any tangent to the plate element shall not intersect with a plate element with an opposite polarity or with any part of the plate element itself. Where however the primary plane of a plate element is perpendicular to the primary plane of the other plate of the pair the plate elements are not regarded as overlapping.

Offset in relation to plate elements of a dipole pair applies to plate element primary plane surfaces when parallel. The offset is the measure of separation between the parallel primary planes. To measure an offset for plate elements whose primary plane is not shared or are not parallel, first identify a rectangular outline for each plate element. Then correct any axial rotation between the plate elements by rotating one element about its length (or if appropriate width) axis so the outline edges representing the closest edge between each plate element are parallel. Then rotate both plate elements equally about their closest edge so that the primary planes are shared or are parallel.

The offset is the distance between parallel planes. If there is no primary plane, such as with an even curvature, then it is the plane of the tangent closest the other element.

Paired Plate Elements means a dipole wherein each plate element of a pair is isolated from the other plate element of the pair arranged in such a manner as they are not overlapping. Paired plate elements need not be identical in size, shape, composition or orientation.

Passive Gain Device refers to a device that is not electrically connected to the dipole elements but which increases the signal gain of the antenna. Examples of passive gain devices include director elements commonly seen on the front of an antenna and the gain plate disclosed in patent NZ504042 referred to above.

Phase Connector refers to the connection between a plate element and a secondary element. A phase connector provides an offset or separation between elements. A phase connector is a type of feedline.

Plate element means an electrically conducting object defining a primary plane surface area which is substantially flat. The plate may be formed from solid material or may have a variety of regular or irregular holes or patterns. A plate can be a mesh or a skeleton. The plate may be any shape, including rectangles, ellipses or other shapes. The range of shapes excludes paired bowtie elements except where in a pair of plates one is rotated approximately 90 degrees about a common, or offset common, axis. Use of non-paired bowtie shaped elements is permitted. Unless stated otherwise a plate element has a width to length ratio of greater than one width unit to ten length units.

Plate Length and Plate Width. Measurement of plate length and width depends on any Attachments to the plates. A plate is measured in a flattened state.

If there are no Attachments to either plate of a pair then the length of each plate is the maximum length of the longest side of the plate and the width is the maximum width of the side of the plate measured perpendicular to the length. Should the plate length and width measurements be equal not including any dipole additions then either measurement may be chosen as the length provided no additions are attached to the chosen length side. A plate is measured in the unfolded/uncurved state.

If there are Attachments to the plates or the antenna of the invention then the width of the plate is assessed as the maximum width of the plate including any additions. The length in this case is assessed as the maximum length measurement of the plate excluding any additions.

Polarity is used in two contexts. The first context is the polarity of the signal being sent or received by the antenna, horizontal, vertical or circular. The second context refers to the relative charge on a dipole element and is associated with the polarity difference between a cable screen or core, or the inputs to a balun, amplifier or other electrical device as applicable.

Rotated about axis means that one plate element is rotated about the central axis that is common to the plate elements of a pair, or would be common but for an offset and/or angular deviation of the one plate element from the common axis.

Standard element refers to non-plate elements and includes elements formed to harmonic wavelength usually a strip or rod. It includes a folded or curved standard element, a half-bowtie shaped element.

Substantially flat in relation to a plate element means that the primary (large

Scale) surface is flat or nearly flat, however curves or folds may form a secondary (small scale) structure. For example, a corrugated sheet will have a primary planar configuration and is substantially flat, although its small scale secondary structure will not be planar.

SUMMARY OF INVENTION

It is the object of the present invention to improve broadband antenna design and performance of at least provide the public with useful choices in broadband antenna design using plate elements.

In particular, designs are given for a high power broadband broadcast antenna, and a broadband high gain reception antenna, methods disclosed on how to arrange and combine plate elements that will extend the bandwidth and/or increase gain. Preferred configurations of elements are provided for multiple or dual polarisation in a single antenna, and antenna design features are disclosed to provide the basis for cost-effective, flexible, and versatile construction of broadband antennas.

Inventive disclosures include:

1. Use of a single plate element paired with a standard non-plate element with each element electrically connected to a different cable polarity. 2. Use of a plate element electrically connected to a standard dipole element and further including a configuration where the standard dipole element is folded. Both connection polarities are connected to the antenna in different places as described. It has been established that antennas using this configuration can provide broadband signal, can have an almost perfect SWR reading suitable for transmitting at high power, and are smaller than comparable conventional antennas.

3. Use of paired isolated plate elements and the preferred connections thereto via an edge zone and in particular arranged in a not overlapping manner. 4. Use of paired isolated plate elements in an edge-on configuration that maximises sensitivity to the signal's magnetic component and when horizontally polarised maximises sensitivity to earth plane reflections.

5. An indirect pairing array wherein paired plate elements are not located immediately adjacent its pair but rather multiple elements are arranged as a set which is mirrored and each element is paired with it's mirror opposite through phase tuned feedlines.

6. A preferred technique to connect (daisy-chain) a plate element with other elements is disclosed. Normally, where dipoles are combined the connection point will be along a central axis. In this disclosure the feeds between dipoles connect to a corner section of the plate elements.

7. A method to determine the appropriate offset displacement and correct length of phase connector when combining plate element pairs with standard element pairs is disclosed.

8. Arrangement of a plate element pair to achieve circular polarisation. 9. Combining paired plate elements with dipole elements to achieve dual polarisation using a phase connector.

10. A mounting body arrangement that provides vertical, horizontal and circular polarisation mounting and edge-on mounting thus allowing single or dual polarisation of the antenna.

DESCRIPTION OF DRAWINGS

Figure 1 - An antenna comprising a single plate element paired with a non-plate element each to opposite polarities.

Figure 2 - An antenna comprising a folded standard dipole element with each end connected to an opposing cable polarity with a single plate element connected via a feedline. Figure 3 - An antenna comprising a pair of plate elements each connected via the edge zone to a different cable polarity, illustrating the corner zone and a vertical polarisation.

Figure 4 - An antenna comprising a pair of plate elements each connected via the edge zone to a different cable polarity, and connected via a phase connector to a pair of standard folded elements, each illustrating horizontal polarisation.

Figure 5 - An antenna comprising a pair of standard folded elements, each connected to a different cable polarity, and connected with a phase connector to the corner zone of a plate element. Polarisation is horizontal. Figure 6 - A dual polarisation antenna comprising a pair of standard folded elements

(vertical), each connected to a different cable polarity, and connected with a phase connector to the corner zone of a plate element (horizontal).

Figure 7 - A dual polarisation antenna (horizontal and circular) comprising a pair of standard folded elements (horizontal), each connected to a different cable polarity, and connected with a phase connector to the corner zone of a plate element. Circular polarisation is achieved by the arrangement and combination of the plate elements.

Figure 8 - An antenna with circular polarisation comprising a plate element pair each connected to a distinct cable polarity with one plate element face on vertically polarised and the other edge on horizontally polarised. Figure 9 - An antenna comprising multiple plate elements configured in sets in an indirect pairing array. In this configuration sets of plate elements are paired, rather than the plates themselves. All plate elements are in phase because feedline length is equivalent. A dual polarised antenna is depicted. The arrangement of plate elements can be varied to achieve different antenna characteristics. Figure 10 - A view of the dual orientation V-block is shown as a method to enable both vertical and horizontal orientation of the antenna. The dual V-block enables clamping to a mast in either orientation through the provision of dual U-bolt mounts.

Figure 11 - Illustrates the concept of primary plane in relation to non-flat plate elements containing curves and/or folds. Figure 1 La. shows a corrugated plate element with no flat area but which nevertheless has a primary plane. Figure 1 l.b shows a plate edge-on with a fold at the left hand side and a curve at the right hand side and further indicates the primary plane in this example.

Figure 12 - Illustrates a curved plate element with no primary plane and the appropriate treatment when considering such plate in the context perpendicular projection for the "not overlapping" requirement. In particular the plate surface area is projected from all tangents. Figure 13 - Provides an illustration of several alignment and body configuration concepts. It illustrates plate elements, standard folded dipoles and gain plates polarised vertically and horizontally.

A single mount V-block with adjustable body orientation is shown as a method to enable both horizontal and vertical alignment of the antenna.

An orientation adjustable standard element mount is shown as a method to allow the standard element polarisation to be aligned independent of the boom and/or plate element alignment. The example shown is a rectangular spline mount, but other shapes are envisaged such as circular or star splines, or a clamp arrangement, possibly with two or more pieces clamped to form the mount.

An orientation adjustable body section is shown, this may be aligned vertically or horizontally with respect to the boom as indicated by to position of plate element mounts on the left hand side of the image. Although not shown it is envisaged that mounting points or arms could extend from the body/boom in both the vertical and horizontal alignments. An orientation adjustable plate element mount is shown as a method to allow the plate element aligned in a face-on or edge-on configuration. The example shown is configured as a cross but other shapes are envisaged such as tubular, flat and T section mounts. Another alternative is to extend mounting arms out from the boom and mount plate elements directly on these arms. Such mounts may offer multiple mounting points to allow the plate elements to be mounted edge-on or face-on, vertically or horizontally.

An orientation adjustable gain plate mount is shown as a method to allow the gain plate to be aligned independent of the body and/or plate element alignment.

Figure 14 - Demonstrates a further approach to the antenna design incorporating a single piece body that can be mounted vertically or horizontally on the integrated dual position V- block thus providing vertical or horizontal alignment for the standard elements. The plate element section offers several mounting positions allowing the plate elements to be aligned in common with the standard elements, edge-on, or in the opposite alignment to the standard elements or in a circular alignment, or a combination of edge-on and face-on mountings.

Claims

1. An antenna comprising a plate element and a standard non-plate element where each element is electrically connected to an opposite cable polarity.

2. An antenna comprising a plate element and a folded standard non-plate element where each end of the folded element is electrically connected to an opposite cable polarity and the plate element is electrically connected to the folded element by a phase connector.

3. An antenna comprising a plate element and a folded plate element where each end of the folded element is electrically connected to an opposite cable polarity and the plate element is electrically connected to the folded element by a phase connector.

4. An antenna comprising a pair of isolated plate elements that are not overlapping each electrically connected via the edge zone to an opposing polarity.

5. An antenna comprising a pair of isolated plate elements that are not overlapping each electrically connected to an opposing polarity with at least one plate connected via a corner zone.

6. An antenna according to claim 4 or 5 where the plate elements are arranged in a circular polarisation with one element polarised vertically and the other polarised horizontally.

7. An antenna according to claims 4 to 6 where there is an offset between the plate elements.

8. An antenna according to any of claims 4 to 7 where a plate element is rotated about an axis. Such axis may be external to the plate.

9. An antenna according to any of claims 4 to 8 further including two isolated standard elements, each electrically connected to a plate element corner zone via a phase connector.

10. An antenna according to claim 4 and claims 6 to 7 wherein the antenna's cable connection occurs edge zone of opposed plate elements.

11. An antenna according to claim 4 to 9 wherein the antenna's cable connection occurs via the opposed standard elements.

12. An antenna according to any of claims 9 to 11 providing dual polarisation wherein the two standard dipoles are aligned to a different signal polarity from the plate elements where the plate elements are aligned to horizontal, vertical or circular signal polarisation. An antenna comprising an indirect pairing array wherein a paired plate elements is not located immediately adjacent its pair but rather multiple elements are arranged as a set which is mirrored and each element is paired with it's mirror opposite through phase tuned feedlines. Each element set is isolated from the other and is connected to a different cable polarity.

13. An antenna according to any of claims 1 to 13 further including any one or more of the following features:

(a) Plate element minimum length of 200mm and maximum length of 300mm;

(b) Plate element minimum width of 120mm;

(c) A separation between Plate elements excluding mounting brackets of at least 120mm. (d) Standard element minimum length including phase connector length of

1250mm and maximum length of 2000mm;

(e) Where standard element is folded the addition of 200mm overall length.

(f) A separation between plate elements and standard element mounting points of at least 100mm. (g) Separation via feedline or phase connector between the elements of at least

2.5%, (preferably at least 5%), of the length of the standard element length;

(h) A minimum separation between plate elements of 10% of plate element length;

(i) A minimum separation between plate elements of 25% of plate element length;

(j) Each plate element having a width to length ratio of greater than 25%; (k) One or more plate elements including folds, curves and/or discontinuities;

(1) One or more passive gain devices;

(m) One or more gain plates aligned in an edge-on configuration;

(n) One or more gain plates aligned to the opposite polarisation of the closest dipole element; (0) Further including a balun, amplifier or frequency transposer;

14. An antenna according to claim 14 wherein measurements 14(a), (b), (c), (d), (e) and (f) are scaled in proportion relative to each other.

15. An antenna according to any of claims 1 to 15 including further pairs of isolated elements each element of a pair being electrically connected to one polarity of the antenna cable.

16. An antenna body construction allowing the mounting of elements in any one or more of the following configurations:

(a) Plate element pair primary plane front facing vertical polarisation; (b) Plate element pair primary plane front facing horizontal polarisation;

(c) Plate element pair primary plane front facing circular polarisation;

(d) One or more plate elements or pair edge facing vertically polarised;

(e) One or more plate elements of pair edge facing horizontally polarised;

(f) Further including a standard element pair mounted with vertical polarisation; (g) (Further) including a standard element pair mounted with horizontal polarisation;

(h) Gain plate mounting with vertical polarisation;

(1) Gain plate mounting with horizontal polarisation.

17. An antenna body construction including a dual polarity orientation moulded V- mounting block.

18. An antenna body construction including a dual position or multiple standard dipole mounting section. The antenna body may comprise of one or more pieces.

19. An antenna body construction including a dual position plate element dipole mounting section. The antenna body may comprise of one or more pieces.

20. An antenna body construction including multiple mounting points to allow for plate elements to be mounted horizontally or vertically, edge-on or face on, and/or standard elements to be mounted horizontally or vertically. The antenna body may comprise of one or more pieces.

21. The subclaims of claims 14 and 17 may be treated and referenced as separate and distinct claims for the purpose of any revisions.

22. The foregoing claims describe the invention including preferred forms thereof.

Alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated within the scope hereof as defined in these accompanying claims.