WO2002056653A2

WO2002056653A2 - Antenna configuration in or on dielectric bodies

Info

Publication number: WO2002056653A2
Application number: PCT/ZA2002/000002
Authority: WO
Inventors: Andries Petrus Cronje Fourie; Michael Crooke
Original assignee: Poynting Innovations (Pty) Limited
Priority date: 2001-01-11
Filing date: 2002-01-11
Publication date: 2002-07-18
Also published as: WO2002056653A3

Abstract

A method of producing a configuration of conductors (42) on a first body (44) comprises the steps of utilizing at least part of the first body (44) as part of a mould (44, 46, 48) and permanently forming at least one moulded conductor (40) of the configuration of conductors (42) on the first body by moulding a molten conductive material in the mould. The method is used to form antenna arrangements on a dielectric first body.

Description

INTRODUCTION AND BACKGROUND

THIS invention relates to configurations of conductors, for example antenna configurations in or on dielectric bodies and a method of producing same.

SUMMARY OF THE INVENTION

According to the invention, there is provided a method of producing a conductor on a first body comprising the steps of: utilizing at least part of the body as part of a mould; and permanently forming at least one moulded conductor on the body by moulding a molten electricity conductive material in the mould.

The step of moulding the conductive material in the mould may comprise casting the material in the mould. In other embodiments, the material may be introduced or injected under pressure into the mould.

The first body may be made of a dielectric material. Alternatively the first body may be coated with a dielectric material.

The mould may define a cavity wholly enclosed by the first body. In other embodiments, the mould may define a cavity enclosed collectively by the first body and a second or foreign body. The cavity may be defined in the first body only and may be closed off by the foreign body, so that the moulded conductor is flush with the first body. Alternatively, the cavity may partially be defined by the first body and partially by the foreign body, so that when the foreign body is removed, the moulded conductor is embedded in and stands proud of the first body. Yet further alternatively, the cavity may be wholly defined by the foreign body and may be closed off by the first body, so that when the foreign body is removed, the moulded conductor lies on, but is secured to the first body.

The moulded conductor may be anchored to the first body by moulding a tenon integrally with the conductor.

The first body may be a flat, thin body or substrate alternatively it may have any other three-dimensional shape.

The second body may be made of a dielectric material such as glass, alternatively it may be made of a metal cladded with a suitable non-bonding or lubricating agent.

The cavity may have a uniform depth. In other embodiments, the depth may vary, to promote inflow of the molten material. Pillars may be provided in the cavity to support part of the mould during at least the moulding step.

At least part of the mould may be heated before and/or during the moulding step.

The method may also comprise the step of electrically connecting at least one electronic component to the conductor by positioning a contract of the component in the cavity before the moulding step.

The conductive material may be solder.

The invention also extends to a circuit comprising at least one conductor permanently formed on a first body by a moulding process.

The body may be made of a dielectric material such as a plastics material having first and second faces. The body is preferably in the form of a board, sheet or pane having opposed first and second faces.

The conductor may form part of a conductor configuration. Part of the configuration may be formed on the first face by the moulding process and another part of the configuration may be formed on the second face by the moulding process.

A second body may be superimposed on the first body with a first face of the second body abutting in an abutting region against the second face of the first body, and the conductor is preferably formed in the abutting region.

The conductor may form part of an antenna. The antenna may be one of a patch antenna, a dipole antenna and a fan dipole antenna.

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 diagrammatic illustration of a first step of a method according to the invention of producing a configuration of conductors, more particularly a patch antenna array; figure 2 is a diagrammatic illustration of a next step in the method according to the invention; figure 3 is a diagrammatic illustration of a third step in the method; figure 4 is a diagrammatic illustration of a further step in the method and also a sectional view of a configuration of conductors according to the invention in the form of a patch antenna array; figure 5 is a side elevation of a first mould for forming a conductor of a conductor arrangement in accordance with the method of the invention; figure 6 is a similar view of a second mould for forming a conductor of a conductor arrangement in accordance with the method of the invention; figure 7 is a similar view of a third mould for forming a conductor of a conductor arrangement in accordance with the method of the invention; figure 8 is a diagrammatic perspective view of a dipole antenna according to the invention formed on opposite faces of a dielectric substrate in accordance with the method of the invention; figure 9 is an elevational view of a fan dipole antenna formed in accordance with the method of the invention; and figure 10 is a section on line X in figure 9.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION A circuit according to the invention in the form of a patch antenna array is generally designated by the reference numeral 10 in figure 4. The array is permanently embedded in a rectilinear dielectric body 12. The body comprises dielectric layers 12.1 to 12.4 superimposed on one another.

The array 10 comprises four co-planar and similar patches or radiating elements of which only two elements namely, elements 14.1 and 14.2 are shown in figure 4. A third element (not shown) is located behind and spaced from element 14.1 and a fourth element (also not shown) is located behind and spaced from element 14.2. The array further comprises a conductive ground plane 16 spaced from the patch elements. Four conductors (of which only two conductors namely, conductors 18.1 and 18.2 are shown) connect each of the patch elements respectively to the ground plane 16 and extend further beyond the ground plane to terminate in transmission lines 20 which in turn are spaced from the ground plane.

The method according to the invention of producing the patch array 10 is illustrated in figures 1 to 4, both inclusive. As will be seen in figures 1 to 3, a cavity 22 for forming the transmission lines 20 is provided in one face 12.21 of layer 12.2 so that when layer 12.2 is located on layer 12.1 a mould 24 (shown in figure 2) comprising cavity 22 for forming the transmission lines is formed at the interface of layers 12.1 and 12.2.

Similarly, a cavity 26 is formed in one face 12.31 of layer 12.3, so that when layer 12.3 is located on layer 12.2 a mould 28 (shown in figure 2) comprising cavity 26 is formed for the ground plane 16.

Also similarly, four cavities 30.1 to 30.4 are formed in one face 12.41 of layer 12.4, so that when layer 12.4 is located on layer 12.3, four moulds (of which only moulds 32.1 and 32.2 are shown) for the patch elements are formed at the interface of layers 12.4 and 12.3.

As shown in figure 3, four parallel holes (of which only holes 34.1 and 34.2 are shown) are drilled through layers 12.1 to 12.3 of the body 12, to connect each of the aforementioned four cavities respectively to cavity 26 and also to cavity 22, thereby to form a network of communicating cavities and holes. In a further step, a molten electricity conductive material such as solder is allowed to flow into the aforementioned network and allowed to cure. The molten conductive material may be introduced into the network under positive or negative pressure. Hence, a configuration of conductors to form a patch antenna array is moulded in the body 12 permanently to be embedded therein, as shown in figure 4.

In figure 5, there is shown an alternative arrangement of forming at least one conductor 40 of a configuration of conductors 42. The dielectric body is shown at 44 and a cavity 46 is defined in the body. A foreign body 48 closing off the cavity completes the mould. The foreign body may be made of a dielectric material such as glass or of metal, preferably coated with a lubricating layer or non-bonding agent, such as polytetrafluoroethylene (PTFE). Once the conductor has been moulded as herein described, the foreign body is removed, leaving the conductor embedded in the dielectric body 44 to be flush with a top surface of the body. Integral tenons 49 may also be provided to anchor the conductor 40 to the dielectric body 44. At least part of the mould may be heated to and maintained at a required temperature during the moulding step, to facilitate the inflow of the molten material.

A yet further alternative arrangement is illustrated in figure 6. The required cavity 50 is now defined by both the dielectric body 52 and the foreign body 54. After moulding and when the foreign body is removed, the resulting conductor would stand proud of a top surface 52.1 of the dielectric body.

In the arrangement shown in figure 7, the required cavity 58 is defined by the foreign body 60 only. The dielectric body 62 closes off the cavity 58 to complete the mould. By utilizing a suitable bonding agent (not shown) on a top surface 62.1 of the dielectric body, the resulting moulded conductor adheres to the upper surface of the dielectric body.

Another embodiment of a configuration of conductors in the form of a dipole antenna 80 on a dielectric body 82 is shown in figure 8. The dielectric body is in the form of a board or substrate 82 having a first face 84 and a second face 86. A first arm 88 of the antenna and a first line 90 of a paired strip transmission line 92 are formed in the first face of the substrate according to the method described herein with reference to figure 5. Similarly, a second arm 94 and a second line 96 of the paired strip transmission line 92 are formed in the second face 86 of the substrate in accordance with the same method. The result is a dipole antenna 80 integrated on a substrate with electrically conductive parts thereof spaced by the dielectric substrate.

The antenna may be moulded in a single step by providing a single and common inlet nozzle arrangement (not shown) in region 98. The nozzle arrangement is preferably frangible from the substrate, to disconnect lines 90 and 96 therefrom. In figures 9 and 10 there is shown another embodiment of an antenna 100 formed in accordance with the method of the invention.

The antenna is a fan antenna comprising a substrate 102 comprising a sheet of Acrylonitrile Butadene Styrene plastic into which are formed cavities 104 for receiving molten solder. The substrate further defines air release holes 106 communicating with the cavities 104.

As a first step, cable 108 is placed in position with two bared ends of conductors 108.1 and 108.2 thereof extending into the cavities. Molten solder is introduced under pressure into the cavities in accordance with the method described with reference to figure 5. Air in the cavities are displaced through the holes 106, so that the cavities are completely filled with solder 0 and the bared ends of the cable are embedded in the molten solder. The first and foreign bodies are kept clamped together to enable the solder to cure and to trap the bared ends. In other embodiments, conductive terminals or legs of other electronic components may be secured to the resulting conductors 110 in a similar manner.

The substrate 102 may be mounted on a window of a vehicle for the antenna to be connected to a mobile phone, for example, in the vehicle.

Claims

1. A method of producing a conductor on a first body comprising the steps of utilizing at least part of the first body as part of a mould; and permanently forming at least one moulded conductor on the body by moulding a molten electricity conductive material in the mould.

2. A method as described in claim 1 wherein the first body is made of a dielectric material.

3. A method as claimed in claim 1 or claim 2 wherein the mould defines a cavity for receiving the molten material which is enclosed by the first body only.

4. A method as claimed in claim 1 or claim 2 wherein the mould defines a cavity for receiving the molten material which is enclosed by the first body and at least a second body.

5. A method as claimed in claim 4 wherein the cavity is defined in the first body only and is closed off by at least the second body.

A method as claimed in claim 4 wherein the cavity is partially defined by the first body and partially by the second body.

7. A method as claimed in claim 4 wherein the cavity is defined by the second body and closed off by the first body.

8. A method as claimed in any one of claims 1 to 7 wherein the moulded conductor is anchored to the first body by moulding a tenon integrally with the conductor.

9. A method as claimed in any one of the preceding claims wherein the first body comprises one of a sheet of plastics material, a flat board and a pane of glass.

10. A method as claimed in any one of the preceding claims wherein the cavity has a variable depth.

11. A method as claimed in any one of claims 1 to 10 wherein pillars are provided in the cavity to support part of the mould.

12. A method as claimed in any one of the preceding steps wherein at least part of the mould is heated prior to the moulding step.

13. A method as claimed in any one of the preceding claims comprising the step of electrically connecting at least one electronic component to the conductor by positioning a contact of the component in the cavity before the moulding step.

14. A method as claimed in any one of the preceding claims wherein the conductive material is solder.

15. A circuit comprising at least one conductor permanently formed on a first body by a moulding process.

16. A circuit as claimed in claim 15 wherein the first body is made of a dielectric material having first and second faces.

17. A circuit as claimed in claim 16 wherein the conductor forms part of a conductor configuration and wherein part of the configuration is formed on the first face by a moulding process and another part of the configuration is formed on the second face by a moulding process.

18. A circuit as claimed in claim 16 wherein a second body is superimposed on the first body with a first face of the second body abutting in an abutting region against the second face of the first body and wherein the conductor is formed at the abutting region.

19. A circuit as claimed in any one of claims 15 to 18 wherein the conductor forms part of an antenna.

0. A circuit as claimed in claim 19 wherein the antenna is one of a patch antenna, a dipole antenna and a fan dipole antenna.