Abstract:
A method of manufacturing an antenna including providing a dielectric core which does not contain an electrical conductor, forming a layer of an electrically conductive material on the core and providing an electrically insulative tube over the core and over the layer of the electrically conductive material.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    Reference is made to U.S. Provisional Patent Application Ser. No. 60/994,950, filed Sep. 20, 2007 and entitled “MULTI-LAYER CONDUCTIVE TUBE ANTENNA,” the disclosure of which is hereby incorporated by reference and priority of which is hereby claimed pursuant to 37 CFR 1.78(a) (4) and (5)(i). 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to antennas and methods of manufacture thereof. 
       BACKGROUND OF THE INVENTION 
       [0003]    The following U.S. patent publications are believed to represent the current state of the art: U.S. Pat. No. 1,745,096. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention seeks to provide an improved antenna and method for manufacture thereof. 
         [0005]    There is thus provided in accordance with a preferred embodiment of the present invention a method of manufacturing an antenna including providing a dielectric core which does not contain an electrical conductor, forming a layer of an electrically conductive material on the core and providing an electrically insulative tube over the core and over the layer of the electrically conductive material. 
         [0006]    Preferably, the forming includes winding the layer of an electrically conductive material about the core in a manner such that adjacent turns of the electrically conductive material are spaced from each other. 
         [0007]    In accordance with a preferred embodiment, the forming includes wrapping the layer of an electrically conductive material about the core in a manner such that adjacent turns of the electrically conductive material partially overlap each other without touching each other at mutually overlapping regions thereof. Additionally, the winding the layer of an electrically conductive material about the core in a manner such that adjacent turns of the electrically conductive material partially overlap each other without touching each other at mutually overlapping regions thereof includes wrapping an insulatively backed conductive strip about the core in a manner such that adjacent turns of the electrically conductive material partially overlap each other without touching each other at mutually overlapping regions thereof due to the presence therebetween of the strip of electrically insulative material. 
         [0008]    Preferably, the method also includes winding an additional layer of an electrically conductive material about the electrically insulative tube in a manner such that adjacent turns of the electrically conductive material are spaced from each other, extruding an electrically insulative outer tube over the core and over the layer of the electrically conductive material, the electrically insulative tube and the additional layer of the electrically conductive material and providing a galvanic connection between the layer of the electrically conductive material and the additional layer of an electrically conductive material. 
         [0009]    In accordance with a preferred embodiment of the present invention the method also includes winding an additional layer of an electrically conductive material about the electrically insulative tube in a manner such that adjacent turns of the electrically conductive material are spaced from each other, extruding an electrically insulative outer tube over the core and over the layer of the electrically conductive material, the electrically insulative tube and the additional layer of the electrically conductive material and providing a parasitic connection between the layer of the electrically conductive material and the additional layer of an electrically conductive material. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
           [0011]      FIG. 1  is a simplified, partially pictorial illustration of a method of manufacture of an antenna in accordance with one preferred embodiment of the present invention; 
           [0012]      FIG. 2  is a simplified, partially cut away illustration of an antenna body manufactured in accordance with the method of  FIG. 1 ; 
           [0013]      FIG. 3  is a simplified, partially pictorial illustration of a method of manufacture of an antenna in accordance with another preferred embodiment of the present invention; and 
           [0014]      FIG. 4  is a simplified, partially cut away illustration of an antenna body manufactured in accordance with the method of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0015]    Reference is now made to  FIG. 1 , which is a simplified, partially pictorial illustration of a method of manufacture of an antenna in accordance with one preferred embodiment of the present invention, and to  FIG. 2 , which illustrates an antenna body manufactured in accordance with the method of  FIG. 1 . As seen in  FIG. 1 , a plastic core  100 , preferably hollow, is extruded from a suitable dielectric material, such as Santoprene®, by a conventional extruder  102 . 
         [0016]    The plastic core  100  is cooled and allowed to harden and is then wrapped by winding thereover a tape  104 , preferably including an adhesive-backed, electrically insulative underlayer  106 , preferably formed of polyester of thickness 12 μm and of width 6 mm, and an electrically conductive top layer  108 , preferably formed of copper, of thickness 25 μm and width 6 mm. 
         [0017]    The winding is preferably carried out so that adjacent turns of the tape are overlapped to an extent of approximately 25%, as seen with clarity in the enlarged portion of  FIG. 2 . 
         [0018]    The wrapped core, here designated by reference numeral  110 , is fed to a suitable extruder  112  which extrudes an electrically insulative tube  114  over the wrapped core  110 . 
         [0019]    It is noted that extruded plastic core  100 , which is preferably hollow, may alternatively be solid dielectric. Although a conductor may be subsequently located within a hollow portion of core  100 , the core  102  is not extruded over a conductor. 
         [0020]    It is appreciated that due to the provision of the electrically insulative underlayer  106 , adjacent turns of the electrically conductive layer  108  do not touch each other at mutually overlapping regions thereof. 
         [0021]    Reference is now made to  FIG. 3 , which is a simplified, partially pictorial illustration of a method of manufacture of an antenna in accordance with one preferred embodiment of the present invention, and to  FIG. 4 , which illustrates an antenna body manufactured in accordance with the method of  FIG. 3 . As seen in  FIG. 3 , a plastic core  150 , preferably hollow, is extruded from a suitable dielectric material, such as Santoprene®, by a conventional extruder  152 . 
         [0022]    The plastic core  150  is cooled and allowed to harden and is then wound with a tape  154 , preferably formed of copper, of thickness 25 μm and width 6 mm. 
         [0023]    The winding is preferably carried out so that adjacent turns of the tape  154  do not overlap. 
         [0024]    The wound core, here designated by reference numeral  160 , is fed to a suitable extruder  162  which extrudes an electrically insulative tube  164  over the wound core  110 . A tape  166  is then wound over electrically insulative tube  164 , preferably in a sense opposite to the winding of tape  154 . The winding is preferably carried out so that adjacent turns of the tape  166  do not overlap. 
         [0025]    The double wound core, here designated by reference numeral  170 , is fed to a suitable extruder  172  which extrudes an electrically insulative tube  174  over the double wound core  170 . 
         [0026]    It is noted that extruded plastic core  150 , which is preferably hollow, may alternatively be solid dielectric. Although a conductor may be subsequently located within a hollow portion of core  150 , the core  150  is not extruded over a conductor. 
         [0027]    A galvanic or parasitic interconnection (not shown) between electrically conductive tapes  154  and  166  is preferably provided. 
         [0028]    In all of the embodiments described hereinabove, a suitable antenna feed connection (not shown) is preferably coupled to the electrically conductive winding at a first end thereof. 
         [0029]    It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of features recited in the claims as well as modifications thereof which would occur to a person of ordinary skill in the art upon reading the foregoing and which are not in the prior art.