WO2000013259A1

WO2000013259A1 - Flexible antenna

Info

Publication number: WO2000013259A1
Application number: PCT/US1999/020083
Authority: WO
Inventors: Paul E. Miller; Thomas H. Seekman
Original assignee: R.A. Miller Industries, Inc.
Priority date: 1998-09-02
Filing date: 1999-09-02
Publication date: 2000-03-09
Also published as: AU6495899A

Abstract

A flexible wire antenna (101) such as may be used on a portable radio pack (100) for military applications and the like is constructed of an alloy of nickel and titanium that is commercially available under the trade name Tinel*. The antenna (101) is also useful as a radio antenna for vehicles where the antenna (101) may come in contact with overhead objects or the like. The antenna (101) has the property about it that it is flexible and restores to an upright position after bending.

Description

FLEXIBLE ANTENNA

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to antennas for radios and other communication systems and particularly to antennas for use in applications where lightweight, flexible antennas are preferred.

Related Art

Portable radio packs, such as may be carried, for example, by military ground forces in field operations, typically include an exposed antenna. The antenna is preferably flexible to allow the antenna to bend without damaging the antenna or impeding movement of a person carrying a radio pack to which the antenna is attached. Bending of the antenna typically occurs when a person carrying a radio pack with an attached external antenna encounters obstacles that come in contact with the antenna, such as typically occurs in military operation in a congested terrain. One prior art antenna structure commonly used on radios carried by military personnel comprises a plurality of substantially flat metallic layers or leaves disposed adjacent of one another. Such a structure will allow the antenna to bend only when a force is applied to the antenna in a preferred direction, i.e., extending substantially perpendicular to the flat surface of the metallic leaves. A disadvantage of such a structure is that it tends to be nearly inflexible in directions perpendicular, or nearly perpendicular, to the preferred direction of bending. A further disadvantage of such an antenna structure, particularly when used for radios carried by personnel, is the substantial weight of the antenna. Furthermore, an antenna constructed of a plurality of leaves tends to generate a noise when the antenna is bent and generally has a relatively large profile. Both noise and large profile are undesirable properties for military operations. A further disadvantage of such a prior art antenna is the high production costs since special dies are required for the production of the leaves and the antenna is expensive to assemble.

Antennas used on vehicles are often mounted on helical springs that allow the antenna to be restored to an upright position after coming in contact with an object. A problem with spring-mounted antennas, particularly when mounted on military vehicles or farm tractors and the like that come in contact with brush or other objects, is that branches or other foreign objects tend to lodge in the helical spring. Such objects eventually cause the spring to be deformed to the point where it can no longer keep the antenna in the proper position and must be replaced. Standard automobile antennas are often damaged by contact with garage doors or other obstacles, such as car washing apparatus.

SUMMARY OF THE INVENTION These and other problems of prior art antennas are overcome in accordance with the present invention, by an antenna constructed of a single, highly elastic wire constructed of an alloy of Nickel and Titanium that is commercially available under the trade name Tinel^*. Advantageously, the antenna of the present invention is highly elastic, is lightweight and resists corrosion and fatigue. Furthermore, the antenna of this invention lends itself particularly well for use on portable radio packs, such as are used by military personnel, since the antenna is light weight, is self restoring and, unlike prior art radio pack antennas, does not make noise when it bends. The highly flexible antenna of this invention is particularly advantageous for use on military vehicles, farm tractors, and the like, where an antenna must be able to bend and be self restoring after coming in contact with an object. Furthermore, the antenna of the present invention is particularly advantageous for use on automobiles, since the antenna will bend through a large angle and will restore itself after being bent from a contact with obstacles such as overhead garage doors, cleaning apparatus in car washes, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of a personnel radio pack with an antenna in accordance with the principles of this invention; FIG. 2 is a schematic representation of a radio installation in a vehicle with an antenna in accordance with the present invention; and

Tinel is a trademark of Raychem Corporation. FIG. 3 is a partial cut-away view of an antenna in combination with a supporting sleeve.

DETAILED DESCRIPTION FIG. 1 is a representation of a portable pack 100, such as might be carried by military personnel or the like. The pack 100 preferably has a rigid outer shell 103 which may be made of metal or synthetic material such as plastic or the like. A wire antenna 101 is mounted to the rigid outer shell 103 by means of an antenna mount 105 and is electrically insulated from the outer shell 103 in a standard fashion. The antenna 101 is connected via conductor 108 to a radio circuit 110. The radio circuit 110 is connected via a wire cable 125 to a headset 115, provided with earphones 118 and a microphone 120. The radio circuit 110 and the headset 115 are well known and commercially available.

The antenna 101 comprises an antenna wire 102 preferably constructed of a commercially available alloy of nickel and titanium, sold under the trade name Tinel* which is a commercially available product, available from Raychem Corporation, Menlo Park, California. Tinel has been found to be an excellent conductor in the radio frequency range for radio reception and transmission purposes. The super elastic properties of Tinel* provide a highly flexible antenna having the property that it is self-restoring over a wide range of radii of bending. The antenna wire 102 preferably has a diameter of approximately 0.1 inch or smaller. In one particular embodiment of the invention, an antenna wire having a diameter of 0.078 inches and a length of 34 inches is used on a portable radio pack such as depicted in

FIG. 1. An antenna wire of these dimensions has been found to be very flexible and self- restoring.

Referring again to FIG. 1, the lower end of the antenna wire 102 is preferably press-fit into a brass or stainless steel ferrule 104 to establish an electrical connection to the antenna wire 102. The ferrule 104 is supported by an insulating bushing 105 or the like mounted to the outer shell 103. A conductor 108 extends between the ferrule 104 and the radio circuit 110.

The Tinel* wire antenna may be readily mounted on a vehicle, such as a tractor or military all terrain vehicle or an automobile, or the like, connected to a vehicle radio in a standard fashion. FIG. 2 is a block diagram representation of a radio antenna 150 mounted on a vehicle fender 152 or the like. An antenna 150, constructed of Tinel*, is shown in combination with an AM/FM radio set 160 such as may be used in various kinds of vehicles and typically includes a receiver 162 and a standard network 165. The antenna 150 is mounted to an electrically conducting ferrule 151 by a press fit, or the like. Ferrule 151 is mounted on an antenna mount 155 extending through vehicle fender 152 or the like. An electrical conductor 154, extending from the ferrule 151, connects the radio set 160. To maintain high flexibility of the antenna 150, the antenna preferably has a diameter of approximately 0.1 inches or less. The antenna preferably has a length of approximately 34 inches and the network 165 may include a loading coil to provide an electrical load to the antenna, in a well known manner, in order to attain the electrical characteristics of the antenna desired in the AM/FM frequency range.

FIG. 3 is a partial cut-away view of the antenna 150 supported within a supporting cover 170. When the antenna 150, constructed of Tinel* and having a diameter on the order of 0.08 inch or smaller is installed on a vehicle, the antenna may have a tendency to bend and to swing in different directions due to movement of the vehicle, especially on rough terrain. In order to dampen the movement of the antenna, a sleeve 170 is extended over a part of or the full length of the antenna. When used with a typical AM/FM antenna having a length of about 30 inches, a plastic sleeve having a wall thickness on the order of 0.02 inches and extending over a major portion of the length of the antenna has been found to stabilize the antenna without impeding the restoring action of the antenna after the antenna has been bent due to contact with an obstacle.

It will be understood that the embodiments described herein are merely illustrative applications of the principles of the invention and that other applications and arrangements may be devised by those skilled in the art or without departing from the spirit and scope of the invention.

Claims

1. A radio antenna comprising a length of flexible conductive wire consisting of an alloy of nickel and titanium.

2. The antenna in accordance with claim 1 wherein the antenna has a diameter in a range between 0.07 and 0.1 inches.

3. The antenna in accordance with claim 1 wherein the alloy is the specific alloy of nickel and titanium known as Tinel*.

4. The antenna in accordance with claim 3 wherein the antenna has a diameter in a range between 0.07 and 0.1 inches.

5. The antenna in accordance with claim 1 wherein the antenna comprises a lower end and an electrically conducting contact member mounted to the lower end.

6. The antenna in accordance with claim 5 wherein the contact member comprises an electrically conducting ferrule.

7. In combination, a portable radio pack comprising a radio circuit and a radio antenna connected to the radio circuit and wherein the antenna comprises a flexible conductive wire consisting an alloy of nickel and titanium having.

8. The combination in accordance with claim 7 wherein the alloy is the specific alloy of nickel and titanium known as Tinel*.

9. The antenna in accordance with claim 7 wherein the antenna comprises a lower end and an electrically conducting contact member mounted to the lower end and electrically connected to the radio circuit.

10. The antenna in accordance with claim 9 wherein the contact member comprises an electrically conducting ferrule.

11. The antenna in accordance with claim 10 wherein the ferrule is formed of brass.

12. The antenna in accordance with claim 10 wherein the ferrule is formed of stainless steel.

13. The antenna in accordance with claim 7 wherein the antenna wire has an approximate length of 30 inches.

14. A flexible radio antenna adapted to be mounted to a vehicle and comprising a conductive wire consisting of an alloy of nickel and titanium and having a predefined length.

15. The antenna in accordance with claim 14 wherein the alloy is the specific alloy of nickel and titanium known as Tinel*.

16. The antenna in accordance with claim 14 wherein the antenna has an upper end and a lower end and an electrically conductive ferrule mounted to the lower end for connection to a radio set.

17. The antenna in accordance with claim 14 wherein the ferrule is formed of brass.

18. The antenna in accordance with claim 14 wherein the ferrule is formed of stainless steel.

19. The antenna in accordance with claim 14 wherein the antenna wire has an approximate length of 30 inches.

20. The antenna in accordance with claim 14 and further comprising a plastic tubular section extending over at least a portion of said predefined length.