Method of manufacturing an internal antenna, and antenna element
View Patent ↗The invention relates to a method of manufacturing a structure suitable as an internal antenna in small radio devices, and an antenna element to which the method is applied. The antenna element comprises a radiating plane and additionally e.g. supportive elements, a feed conductor and short-circuit conductor as well as extensions to increase capacitance. The antenna element is fabricated by first extruding from a billet an antenna billet, and working the latter as required. The antenna billet may be symmetrical so that two antenna elements will be produced when it is cut in half. Advantageously the antenna element is fabricated so as to conform with the covering of the device in which it is placed. It may also be part of a covering of a device. The manufacturing costs of the antenna element are relatively low and the radio characteristics of the element are good. An antenna structure employing the element has got few separate parts and is mechanically firm and space-conserving.
1. A method of manufacturing an internal antenna for a radio device by forming a single-piece conductive antenna element comprising a radiating plane of the antenna, the method comprising the steps of;
extruding an antenna billet, having substantially a shape of the antenna element, from a basic billet;
the extruded antenna billet comprises extensions of the radiating plane including a feed conductor, a short-circuit conductor, and at least one other extruded conductive support leg; and
removing conductive material from the antenna billet so as to shape at least one of the radiating plane of the antenna and one of the extensions.
2. The method according to claim 1 , further comprising the step of:
cutting apart two symmetrically facing halves of the antenna billet having substantially the shape of the antenna element so as to produce two mutually identical antenna elements.
3. The method according to claim 1 , wherein the basic billet is extruded so that said extensions of the radiating plane further comprise at least one part which substantially increases the electrical length of the radiating plane.
4. The method according to claim 1 , wherein the step of removing the conductive material from the antenna billet is achieved by punching its planar portion.
5. The method according to claim 1 , wherein the step of removing the conductive material from the antenna billet is achieved by cutting an extension of its planar portion.
6. The method according to claim 1 , further comprising the step of surface treating the antenna element.
7. The method according to claim 6 , when the step of surface treating comprises the step of coating at least part of the antenna element with anti-corrosive material which conducts electricity better than the material of the antenna element.
8. The method according to claim 6 , wherein the step of surface treating comprises the step of coating of the outer surface of the antenna element with dielectric material.
9. An antenna element in an internal antenna of a radio device, which element is a unitary extrusion piece comprising a radiating plane and extensions thereof;
the extruded extensions including a feed conductor, a short-circuit conductor, and at least one other extruded conductive support leg.
10. The antenna element according to claim 9 , wherein said extruded extensions of the radiating plane further comprise at least one part which substantially increases the electrical length of the radiating plane.
11. The antenna element according to claim 9 , wherein the extruded feed conductor, short-circuit conductor, and support leg are located in corners of the radiating plane.
12. The antenna element according to claim 11 , wherein at least one extension, which increases the electrical length of the radiating plane, joins to at least one of said feed conductor, short-circuit conductor, and support leg so as to enhance the firmness of the antenna element.
13. The antenna element according to claim 9 , wherein the at least one support leg is located at a point where the electromagnetic field, when the antenna resonates, is substantially weaker than in antenna space on average.
14. The antenna element according to claim 9 , wherein its shape conforms with a shape of a portion of a cover of the radio device.
15. The antenna element according to claim 14 , wherein the antenna element is part of the cover of the radio device.
16. The antenna element according to claim 9 further including a surface material which is anti-corrosive and improves electrical conductivity.
17. A radio device having an internal antenna, which antenna comprises an antenna element which is a unitary extrusion piece comprising a radiating plane and extensions thereof;
the extruded extensions including a feed conductor, a short-circuit conductor, and at least one other extruded conductive support leg.