GB2385202A

GB2385202A - Antenna with cylindrical core having channels filled with masking material

Info

Publication number: GB2385202A
Application number: GB0203004A
Authority: GB
Inventors: David Ganeshmoorthy; Kandiah Ganeshmoorthy; Richard Ganeshmoorthy
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-08
Filing date: 2002-02-08
Publication date: 2003-08-13
Also published as: WO2003067704A1; GB0203004D0; AU2003209972A1

Abstract

A plastic cylindrical core 11 has moulded into it a series of channels C1,C2,C3 into which masking material M is injected. The channels form the boundaries of predetermined surface areas A1,A2,A3. These surface areas are first etched and then subjected to a deposition process (eg electroplating) thus forming a conducting area of the antenna. The deposited material may be inherently conductive material (eg gold, chrome, nickel, Nichem RTM), or a material which can subsequently be rendered conducting. The core 11 includes a threaded portion 12 by which the antenna may be mounted (eg onto a mobile phone).

Description

METHOD OF MANUFACTURING AND PRODUCT OF THE METHOD This invention relates to a method of manufacturing and product of the method. It is particularly concerned with a the manufacture of antenna.

Antenna for mobile devices, particularly phones, involve the production in large numbers of a device manufactured to close tolerances. Heretofore the design of such antenna has involved the provision of a number of components which are subsequently assembled as a unit for subsequent addition to form a complete device such as a mobile phone.

According to a first aspect of the present invention there is provided a method of manufacturing an antenna subassembly comprising the steps of: manufacturing a core unit of a plastics material in a mould the core unit having a channel or series of channels which channel or channels bounding predetermined surface areas of the core unit; injecting or otherwise inserting into the channel or channels a masking material to form a combined unit comprising core unit and masking material; etching the predetermined surface area to provide a keyed surface to provide for subsequent deposition of material; and subjecting the combined unit to a deposition process whereby the predetermined surface areas of the core unit are coated with an inherently conducting material or a material which can subsequently be rendered conducting; and if required subjecting the coated material to an activation process to render it conducting process.

According to a first preferred version of the first aspect of the present invention the subjecting step involves an inherently conducting material such as Nichem PF-500, Nichem 2700, nickel, chrome or gold.

According to a second aspect of the present invention there is provided an antenna sub-assembly comprising:

a core unit of plastics material, the unit being of substantially cylindrical form, with a longitudinal axis; channels in the core unit serving to bound a predetermined surface area or areas of the core unit' masking material occupying the channel or channels so that the masking material provides boundaries to the or each predetermined surface area; and a deposited layer of conducting material on the predetermined surface area or areas of the core unit; the core unit, masking material and deposited layer forming an antenna for operation at a pre-determined frequency or range of frequencies the core unit including an input conductor whereby the deposited layer can be coupled to a radio circuit.

An exemplary embodiment of the invention will now be described with reference to the accompanying drawings of an antenna unit of which: Figure 1A-C shows sectional elevation of a core unit moulding; Figure 2 A-C shows the core unit of Figure 1 having had injected into it masking material; and Figure 3 shows a number of sections of the core unit shown in Figure 2.

Figure 1A-C variously show a section of core unit 11 which is of plastics material.

The unit 11 has a screwed lower end 12 by means of which the completed antenna is mounted in a working unit such as a mobile phone.

The unit 11 has moulded into it a series of channels, typically channels C, Cl, C2 which serve to provide boundaries to surface areas, for example areas Al, A2, A3, which are of predetermined shape and which form the eventual conducting working region of the antenna. Consequently where required the areas are linked to one another to obtain the required electrical configuration.

Figure 2 shows the unit 11 of Figure 1 following an injection process in the course of which masking material M is injected into the channels C, Cl, C2.

Following the injection process described in connection with Figure 2 the surface of the surface areas Al, A2, A3 are subjected to an etching process to optimise a subsequent deposition process (e. g. electroplating) onto the predetermined surface areas Al-3.

Figure 3 shows cross sections 1-8 along axis A of the unit 11 (Figure 2C) following the injection process described above in connection with Figure2. It shows those regions of the core member 11 which are either masked by material M or open to receive a deposition forming the eventual conducting area of the antenna. The configuration and dimensions of the predetermined areas Al, A2, A3 etc depend on the operating characteristics required in the finished antenna. By using masking material in this way any configuration of predetermined area or areas can be readily achieved. Typically in the example described the lower part of the unit 11 including the screwed section 12 is readily and economically coated with conducting material to provide for good conducting contact between the unit 11 and a socket into which it is screwed.

By means of the invention an efficient and economic design of antenna is achieved Table 1 show the characteristics of various materials which can be deposited on a core unit to produce various characteristics. Various deposition processes can be used including electroless plating and electroplating. In addition if necessary material can be deposited which requires a further treatment to optimise its characteristics in an operational state.

Table 2 shows a number of stages for undertaking various plating processes.

Claims

CLAIMS 1 A method of manufacturing an antenna sub-assembly comprising the steps of: manufacturing a core unit of a plastics material in a mould the core unit having a channel or series of channels which channel or channels bounding predetermined surface areas of the core unit; injecting or otherwise inserting into the channel or channels a masking material to form a combined unit comprising core unit and masking material; etching the predetermined surface area to provide a keyed surface to provide for subsequent deposition of material; and subjecting the combined unit to a deposition process whereby the predetermined surface areas of the core unit are coated with an inherently conducting material or a material which can subsequently be rendered conducting; and, if required, subjecting the coated material to an activation process to render it conducting.
2 A method as claimed in Claim 1 wherein the subjecting step involves an inherently conducting material such as Nichem PF-500, Nichem 2700, nickel, chrome or gold.
3 A antenna sub-assembly comprising core unit of plastics material, the unit being of substantially cylindrical form, with a longitudinal axis; channels in the core unit serving to bound a predetermined surface area or areas of the core unit'masking material occupying the channel or channels so that the masking material provides boundaries to the or each predetermined surface area; and a deposited layer of conducting material on the predetermined surface area or areas of the core unit; the core unit, masking material and deposited layer forming an antenna for operation at a pre-determined frequency or range of frequencies the core unit including an input conductor whereby the deposited layer can be coupled to a radio circuit.