Abstract:
A method for manufacturing antennas including providing a substrate having at least one surface lying in three dimensions and applying a conductive coating to the at least one surface lying in three dimensions, thereby defining an antenna on the at least one surface and an antenna including a conductive coating applied to a three-dimensional surface of a substrate.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    Reference is made to U.S. Provisional Patent Application 60/579,173 filed Jun. 10, 2004 entitled “THREE DIMENSIONAL CPA (CONDUCTIVE POLYMER ANTENNA)”, to U.S. Provisional Patent Application filed Nov. 29, 2004 and entitled “THREE DIMENSIONAL CPA (CONDUCTIVE POLYMER ANTENNA)”, and to U.S. Provisional Patent Application, filed Apr. 28, 2005 entitled “METHOD FOR APPLYING WET CONDUCTIVE MATERIALS ON A  3 D SUBSTRATE”, the disclosures of which are 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 generally and to methods of manufacture thereof. 
       BACKGROUND OF THE INVENTION 
       [0003]    The following patents and published patent applications are believed to represent the current state of the art: 
         [0004]    U.S. Pat. Nos. 6,404,393; 6,115,762; 6,031,505; 4,100,013; 4,242,369; 4,668,533; 6,658,314; 6,259,962; 6,582,979; 6,765,183; 6,249,261; 6,501,437; 6,575,374; 6,735,183; 6,818,985; 6,251,488; 6,636,676; 6,811,744; 6,823,124; 6,642,893; 6,037,906; 6,351,241; 5,204,687 and 5,943,020. 
         [0005]    Published PCT Patent Application WO2004/068389. 
         [0006]    Published U.S. Patent Applications 2004/0197493; 2004/0179808 and 2005/0046664. 
       SUMMARY OF THF INVENTION 
       [0007]    The present invention seeks to provide an improved antenna and methods for manufacturing thereof. 
         [0008]    There is thus provided in accordance with a preferred embodiment of the present invention a method for manufacturing antennas including providing a substrate having at least one surface lying in three dimensions and applying a conductive coating to the at least one surface lying in three dimensions, thereby defining an antenna on the at least one surface. 
         [0009]    There is also provided in accordance with another preferred embodiment of the present invention a method for manufacturing mobile communicators including providing a substrate having at least one surface lying in three dimensions, the substrate defining at least one of a housing portion and a carrier element of a mobile communicator, and applying a conductive coating to the at least one surface lying in three dimensions, thereby defining an antenna on the at least one surface. 
         [0010]    Preferably, the applying a conductive coating includes applying the conductive coating in a predetermined pattern, which corresponds to the configuration of the antenna. Additionally or alternatively, the applying a conductive coating includes applying a conductive polymer coating. Additionally, the applying a conductive polymer coating includes applying at least one of silver and nanoparticles. 
         [0011]    Preferably, the applying a conductive coating includes spraying the conductive coating onto a pre-masked substrate. Additionally or alternatively, the applying a conductive coating includes spraying the conductive coating onto the substrate and thereafter patterning the conductive coating. Alternatively or additionally, the applying a conductive coating includes microdispensing the conductive coating onto the surface. Additionally or alternatively, the applying a conductive coating includes dipping the surface in a conductive coating bath and thereafter patterning the conductive coating. 
         [0012]    Preferably, the applying a conductive coating includes at least one of chemical vapor deposition, physical vapor deposition and electroless plating of a pre-patterned three-dimensional substrate. Alternatively or additionally, the applying a conductive coating includes pad printing at least one of interior portions and non-highly angled portions of the three-dimensional substrate and applying sub-micron conductive particles to at least one of peripheral portions and highly angled portions of the three-dimensional substrate. 
         [0013]    Preferably, the antenna is an embedded antenna. 
         [0014]    There is further provided in accordance with yet another preferred embodiment of the present invention a method for manufacturing a precision three-dimensional conductive layer including providing a substrate having at least one surface having at least a first generally two-dimensional surface portion and at least a second generally three-dimensional surface portion, applying a conductive coating to at least a first generally two-dimensional surface portion and applying sub-micron conductive particles to at least a second generally three-dimensional surface portion, wherein the conductive coating on at least a first generally two-dimensional surface portion and the sub-micron conductive particles on at least a second generally three-dimensional surface portion together define the precision three-dimensional conductive layer. 
         [0015]    Preferably, the applying sub-micron conductive particles includes applying the sub-micron conductive particles in a predetermined pattern, the outer extent of which corresponds to the configuration of the precision three-dimensional conductive layer. Additionally or alternatively, the applying a conductive coating includes applying a conductive polymer coating. Additionally, the applying a conductive polymer coating includes applying at least one of silver and nanoparticles. 
         [0016]    Preferably, the applying a conductive coating utilizes pad printing. Additionally, the precision three-dimensional conductive layer is formed on a plastic support element, which forms part of a mobile communicator. 
         [0017]    There is yet further provided in accordance with still another preferred embodiment of the present invention an antenna including a conductive coating applied as a wet conductive material to at least one three-dimensional surface. 
         [0018]    There is also provided in accordance with yet another preferred embodiment of the present invention an antenna including a conductive coating applied to a three-dimensional surface of a substrate. 
         [0019]    Preferably, the conductive coating is a polymer. More preferably, the polymer includes at least one of silver and nanoparticles. 
         [0020]    There is additionally provided in accordance with another preferred embodiment of the present invention a mobile communicator including a housing portion, a carrier element, at least one of the housing portion and the carrier element defining a substrate having at least one surface lying in three dimensions, and an antenna, the antenna defined by a conductive coating applied to the at least one surface lying in three dimensions. 
         [0021]    Preferably, the conductive coating includes a predetermined pattern, which corresponds to the configuration of the antenna. Additionally, the antenna is embedded in at least one of the housing portion and the carrier element. 
         [0022]    Preferably, the conductive coating is a polymer. More preferably, the polymer includes at least one of silver and nanoparticles. 
         [0023]    There is yet further provided in accordance with another preferred embodiment of the present invention, a precision three-dimensional conductive layer, the conductive layer being applied to at least one support surface having at least a first generally two-dimensional surface portion and at least a second generally three-dimensional surface portion, the conductive layer including a conductive coating applied to at least a first generally two-dimensional surface portion and sub-micron conductive particles applied to at least a second generally three-dimensional surface portion. 
         [0024]    Preferably, the sub-micron conductive particles are applied in a predetermined pattern extending at least generally along the periphery of the precision three-dimensional conductive layer. Additionally or alternatively, the conductive coating is a polymer. Preferably, the polymer includes at least one of silver and nanoparticles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
           [0026]      FIG. 1  is a simplified pictorial illustration of an embedded antenna formed by a wet conductive coating on a three-dimensional substrate, forming part of a mobile communicator, constructed and operative in accordance with a preferred embodiment of the present invention; 
           [0027]      FIG. 2  is a simplified pictorial illustration of the embedded antenna of  FIG. 1 ; 
           [0028]      FIGS. 3A and 3B  are simplified sectional illustrations of the embedded antenna of  FIGS. 1 &amp; 2 , taken along lines IIIA-IIIA and IIIB-IIIB in  FIG. 2 ; 
           [0029]      FIGS. 4A ,  4 B,  4 C,  4 D,  4 E and  4 F are simplified illustrations of six alternative methodologies for producing the embedded antenna of  FIGS. 1-3B ; 
           [0030]      FIG. 5  is a simplified pictorial illustration of an embedded antenna formed by a conductive coating on a three-dimensional plastic support element, forming part of a mobile communicator, constructed and operative in accordance with a preferred embodiment of the present invention; 
           [0031]      FIG. 6  is a simplified pictorial illustration of the embedded antenna of  FIG. 5 ; 
           [0032]      FIG. 7  is a simplified plan view illustration of the embedded antenna of  FIGS. 5 &amp; 6 ; 
           [0033]      FIGS. 8A and 8B  are simplified sectional illustrations of the embedded antenna of  FIGS. 5-7 , taken along lines VIIIA-VIIIA and VIIIB-VIIIM in  FIG. 7 ; 
           [0034]      FIGS. 9A ,  9 B,  9 C,  9 D,  9 E and  9 F are simplified illustrations of six alternative methodologies for producing the embedded antenna of  FIGS. 5-8B ; 
           [0035]      FIG. 10A  is a simplified pictorial exploded view illustration of an external snap-in antenna including a three-dimensional meander radiating element, constructed in accordance with a preferred embodiment of the present invention; 
           [0036]      FIG. 10B  is a simplified pictorial partially assembled view illustration of the antenna of  FIG. 10A ; 
           [0037]      FIG. 10C  is a simplified pictorial fully assembled view illustration of the antenna of  FIGS. 10A &amp; 10B ; 
           [0038]      FIG. 11  is a simplified illustration of methodology for producing the antenna of  FIGS. 10A-10C ; 
           [0039]      FIG. 12A  is a simplified pictorial exploded view illustration of an external retractable top helical antenna having a three-dimensional coil or meander element, constructed in accordance with a preferred embodiment of the present invention; 
           [0040]      FIG. 12B  is a simplified pictorial partially assembled view illustration of the antenna of  FIG. 12A ; 
           [0041]      FIG. 12C  is a simplified pictorial fully assembled view illustration of the antenna of  FIGS. 12A &amp; 12B ; 
           [0042]      FIG. 13  is a simplified illustration of a methodology for producing the antenna of  FIGS. 12A-12C ; 
           [0043]      FIG. 14A  is a simplified pictorial exploded view illustration of an external retractable base helical antenna having two three-dimensional coil or meander elements, constructed in accordance with a preferred embodiment of the present invention; 
           [0044]      FIG. 14B  is a simplified pictorial partially assembled view illustration of the antenna of  FIG. 14A ; 
           [0045]      FIG. 14C  is a simplified pictorial fully assembled view illustration of the antenna of  FIGS. 14A &amp; 14B ; and 
           [0046]      FIG. 15  is a simplified illustration of a methodology for producing the antenna of  FIGS. 14A-14C . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0047]    Reference is now made to  FIG. 1 , which is a simplified pictorial illustration of an embedded antenna, constructed and operative in accordance with a preferred embodiment of the present invention, formed by a conductive coating on a three-dimensional substrate, forming part of a mobile communicator;  FIG. 2 , which is a simplified pictorial illustration of the embedded antenna of  FIG. 1 , showing an antenna pattern created by applying a wet conductive polymer to the substrate and  FIGS. 3A and 3B  which are simplified sectional illustrations of the embedded antenna of  FIGS. 1 &amp; 2 , taken along lines IIIA-IIIA and IIIB-IIIB in  FIG. 2 . 
         [0048]    As seen in  FIGS. 1-3B , an embedded antenna  100  is formed by coating a three-dimensional substrate, such as part of the back casing  102  of a mobile telephone  103 , with a wet conductive coating  104 . The conductive coating  104  preferably comprises silver. Alternatively, the conductive coating may employ any other suitable conductor. Generally, wet conductive materials useful in the present invention preferably comprise conductive polymers, but may also include conductive ink jet inks, pigmented inks, conductive nanopastes, hybrid nanopastes, conductive nanoparticles, microparticles and nanometal powders. Other suitable materials may include Electronic Band-Gap (EBG) structures and Frequency Selective Surface (FSS) materials or other suitable types of metamaterials, such as those described in Research on negative refraction and backward-wave media: A historical perspective by Sergei Tretyakov, EPFL Latsis Symposium 2005; Negative refraction: revisiting electromagnetics from microwaves to optics, Lausanne 28.2-2.03.2005, pp 30-35; On EBG Structures for Cellular Phone Applications, by Filiberto Bilotti et al AEU International Journal of Electronics and Communications 57 (2003) No. 6, 403-408; A Positive Future for Double-Negative Metamaterials, by Nader Engheta et al, IEEE Transactions on Microwave Theory and Techniques, Vol. 53, NO. 4, pp. 1535-1556, April 2005; Application of double negative metamaterials to increase the power radiated by electrically small antennas, by R. W. Aiolkowski et al, IEEE Trans. Antennas Propag., Vol. 51, NO. 10, pp. 2626-2640, October 2003. The disclosures of these publications are hereby incorporated by reference. 
         [0049]    The wet conductive coating may be applied to the three-dimensional substrate by any suitable technique. Examples of suitable techniques include spraying the conductive coating onto a pre-masked substrate as seen in  FIG. 4A ; spraying the conductive coating onto a substrate and thereafter patterning the coating on the substrate as seen in  FIG. 4B ; a combination of the foregoing two examples as seen in  FIG. 4C ; micro-dispensing as seen in  FIG. 4D , preferably employing equipment and techniques commercially available from Dick Blick Art Materials P.O. Box 1267, Galesburg, IL USA, and dipping and subsequent laser patterning as seen in  FIG. 4E . 
         [0050]    Other examples of suitable coating techniques include: chemical vapor deposition, physical vapor deposition and electroless plating of a pre-patterned three-dimensional substrate. 
         [0051]    Another preferred technique, illustrated in  FIG. 4F , is a combination of pad printing of interior and non-highly angled portions, such as portions designated by reference numeral  106 , of the three-dimensional substrate and applying sub-micron conductive particles to the peripheral and highly angled portions of the three-dimensional substrate, such as portions designated by reference numeral  110 . Application of sub-micron conductive particles is preferably effected using equipment, materials and methodologies commercially available from Optomec, Inc. of Albuquerque, N. Mex., USA and described in one or more of their U.S. Pat. Nos. 6,823,124; 6,251,488 and 6,811,744, and published U.S. Patent Applications 2004/0197493; 2004/0179808 and 2005/0046664, the disclosures of which are hereby incorporated by reference. 
         [0052]    Additional techniques which may be employed with suitable adaptations in forming the antennas of  FIGS. 1-3B  are described in Published PCT Patent Application WO 2004/068389 A2, a document entitled Metallizations by Direct-Write Inkjet Printing, NREL/CP-520-31020, published by the National Renewable Energy Laboratory, and a document entitled Materials and Processes for High Speed Printing for Electronic Components, IS &amp; T NIP20: 2004 International Conference on Digital Printing Technologies, pages 275-278, the contents of which are hereby incorporated by reference, and in references mentioned therein, the contents of which are hereby incorporated by reference. 
         [0053]    Reference is now made to  FIG. 5 , which is a simplified pictorial illustration of an embedded antenna formed in accordance with a preferred embodiment of the present invention by applying a wet conductive coating to a three-dimensional plastic element support, forming part of a mobile communicator;  FIG. 6  which is a simplified pictorial illustration of the embedded antenna of  FIG. 5 , showing an antenna pattern created by applying the conductive polymer to the element support;  FIG. 7  which is a simplified plan view illustration of the embedded antenna of  FIGS. 5 &amp; 6  and  FIGS. 8A and 8B  which are simplified sectional illustrations of the embedded antenna of  FIGS. 5-7 , taken along lines VIIIA-VIIIA and VIIIB-VIIIB in  FIG. 7 . 
         [0054]    As seen in  FIGS. 5-8B , an embedded antenna  200  is formed by coating a three-dimensional substrate, such as part of the plastic element carrier  202  of a mobile telephone  203 , with a conductive coating  204 . The conductive coating preferably comprises silver. Alternatively, the conductive coating may employ any other suitable conductor. Generally, conductive materials useful in the present invention preferably comprise conductive polymers but may also include conductive ink jet inks, pigmented inks, conductive nanopastes, hybrid nanopastes, conductive nanoparticles, microparticles and nanometal powders. Other suitable materials may include Electronic Band-Gap (EBG) structures and Frequency Selective Surface (FSS) materials or other suitable types of metamaterials, such as those described in Research on negative refraction and backward-wave media: A historical perspective by Sergei Tretyakov, EPFL Latsis Symposium 2005; Negative refraction: revisiting electromagnetics from microwaves to optics, Lausanne 28.2-2.03.2005, pp 30-35; On EBG Structures for Cellural Phone Applications, by Filiberto Bilotti et al AEU International Journal of Electronics and Communications 57 (2003) No. 6, 403-408; A Positive Future for Double-Negative Metamaterials, by Nader Engheta et al, IEEE Transactions on Microwave Theory and Techniques, Vol. 53, NO. 4, pp. 1535-1556, April 2005; Application of double negative metamaterials to increase the power radiated by electrically small antennas, by R. W. Aiolkowski et al, IEEE Trans. Antennas Propag., Vol. 51, NO. 10, pp. 2626-2640, October 2003. The disclosures of these publications are hereby incorporated by reference. 
         [0055]    The conductive coating may be applied to the three-dimensional substrate by any suitable technique. Examples of suitable techniques include spraying the conductive coating onto a pre-masked substrate as seen in  FIG. 9A ; spraying the conductive coating onto a substrate and thereafter patterning the coating on the substrate and seen in  FIG. 9B ; a combination of the foregoing two examples as seen in  FIG. 9C ; micro-dispensing as seen in  FIG. 9D ; dipping and subsequent laser patterning as seen in  FIG. 9E . 
         [0056]    Other examples of suitable coating techniques include: chemical vapor deposition; physical vapor deposition and electroless plating of a pre-patterned three-dimensional substrate. 
         [0057]    Another preferred technique, illustrated in  FIG. 9F , is a combination of pad printing of interior and non-highly angled portions, such as portions designated by reference numeral  206  of the three-dimensional substrate and applying sub-micron conductive particles to the peripheral and highly angled portions of the three-dimensional substrate, such as portions designated by reference numeral  210 . Application of sub-micron conductive particles is preferably effected using equipment, materials and methodologies commercially available from Optomec, Inc. of Albuquerque, N. Mex., USA and described in one or more of their U.S. Pat. Nos. 6,823,124; 6,251,488 and 6,811,744, and published U.S. Patent Applications 2004/0197493; 2004/0179808 and 2005/0046664, the disclosures of which are hereby incorporated by reference. 
         [0058]    Additional techniques which may be employed with suitable adaptations in forming the antennas of  FIGS. 5-7B  are described in Published PCT Patent Application WO 2004/068389 A2, a document entitled Metallizations by Direct-Write Inkjet Printing, NREL/CP-520-31020, published by the National Renewable Energy Laboratory, and a document entitled Materials and Processes for High Speed Printing for Electronic Components, IS &amp; T NIP20: 2004 International Conference on Digital Printing Technologies, pages 275-278, the contents of which are hereby incorporated by reference, and in references mentioned therein, the contents of which are hereby incorporated by reference. 
         [0059]    Reference is now made to  FIGS. 10A ,  10 B and  10 C, which illustrate an external snap-in antenna including a three-dimensional meander radiating element  500 , constructed in accordance with a preferred embodiment of the present invention. 
         [0060]    As seen particularly clearly in  FIG. 10A , in accordance with a preferred embodiment of the present invention, the meander radiating element  500  is formed by applying a wet conductive material, preferably a conductive polymer, onto a stubby base element  502 , typically injection molded of plastic and having attachment prongs  504  and an internal axial bore  506 . Application of the wet conductive material may be carried out in accordance with any of the methodologies described hereinabove. 
         [0061]    Stubby base element  502  defines a truncated generally conical shaped antenna support surface  508  having a generally elliptical cross section and arranged about a longitudinal axis  510 . The meander radiating element  500  preferably lies about a majority of the circumference of antenna support surface  508  and includes an elongate feed portion  512  which extends to an opening  514 , formed in surface  508  and communicating with internal axial bore  506 , and terminates in a conductor portion  516  disposed on an edge  518  of opening  514 . 
         [0062]    A conductive antenna feed shaft  520  is seated within internal axial bore  506  such that a conductive contact surface  522  thereof is in ohmic contact with conductor portion  516 , thereby establishing electrical contact between feed shaft  520  and meander radiating element  500 . A plurality of circumferential ribs  524  frictionally retain the conductive antenna feed shaft  520  in conductive engagement with conductor portion  516  within bore  506 . A dielectric cover  530  is preferably snap-fit or press-fit over base element  502  and meander radiating element  500  printed thereon. 
         [0063]      FIG. 11  illustrates in a simplified manner a methodology for producing the antenna of  FIGS. 10A-10C , preferably employing application of sub-micron conductive particles to the antenna support surface  508  to define the meander element  500  thereon. Application of sub-micron conductive particles is preferably effected using equipment, materials and methodologies commercially available from Optomec, Inc. of Albuquerque, N. Mex., USA and described in one or more of their U.S. Pat. Nos. 6,823,124; 6,251,488 and 6,811,744, and published U.S. Patent Applications 2004/0197493; 2004/0179808 and 2005/0046664, the disclosures of which are hereby incorporated by reference. Alternatively, any other suitable technique for applying a wet conductive material to surface  508  may be employed for defining the meander element. 
         [0064]    Reference is now made to  FIGS. 12A ,  12 B and  12 C, which illustrate an external retractable top helical antenna constructed and operative in accordance with a preferred embodiment of the present invention and having a three-dimensional coil or meander element  600 , preferably formed by application of sub-micron conductive particles to an antenna support surface  608 . Application of sub-micron conductive particles is preferably effected using equipment, materials and methodologies commercially available from Optomec, Inc. of Albuquerque, N. Mex., USA and described in one or more of their U.S. Pat. Nos. 6,823,124; 6,251,488 and 6,811,744, and published U.S. Patent Applications 2004/0197493; 2004/0179808 and 2005/0046664, the disclosures of which are hereby incorporated by reference. Alternatively, any other suitable technique for applying a wet conductive material to surface  608  may be employed for defining the coil or meander element. 
         [0065]      FIG. 13  illustrates in a simplified manner a methodology for producing the antenna of  FIGS. 12A-12C , preferably employing application of sub-micron conductive particles to the antenna support surface  608  to define the meander element  600  thereon. Application of sub-micron conductive particles is preferably effected using equipment, materials and methodologies commercially available from Optomec, Inc. of Albuquerque, N. Mex., USA and described in one or more of their U.S. Pat. Nos. 6,823,124; 6,251,488 and 6,811,744, and published U.S. Patent Applications 2004/0197493; 2004/0179808 and 2005/0046664, the disclosures of which are hereby incorporated by reference. Alternatively, any other suitable technique for applying a wet conductive material to surface  608  may be employed for defining the meander element. 
         [0066]    Reference is now made to  FIGS. 14A ,  14 B and  14 C, which illustrate an external retractable base helical antenna having two three-dimensional coil or meander elements, constructed in accordance with a preferred embodiment of the present invention. The antenna of  FIGS. 14A-14C  includes a first three-dimensional coil or meander element  700 , preferably formed by application of sub-micron conductive particles to an antenna support surface  708 , and a second three-dimensional coil or meander element  750 , preferably formed by application of sub-micron conductive particles to a whip antenna portion support surface  758 . Application of sub-micron conductive particles is preferably effected using equipment, materials and methodologies commercially available from Optomec, Inc. of Albuquerque, N. Mex., USA and described in one or more of their U.S. Pat. Nos. 6,823,124; 6,251,488 and 6,811,744, and published U.S. Patent Applications 2004/0197493; 2004/0179808 and 2005/0046664, the disclosures of which are hereby incorporated by reference. Alternatively, any other suitable technique for applying a wet conductive material to surfaces  708  and  758  may be employed for defining the coil or meander element. 
         [0067]      FIG. 15  illustrates in a simplified manner a methodology for producing the antenna of  FIGS. 14A-14C , preferably employing application of sub-micron conductive particles to the antenna support surfaces  708  and  758  to define the respective coil or meander elements  700  and  750  printed thereon. Application of sub-micron conductive particles is preferably effected using equipment, materials and methodologies commercially available from Optomec, Inc. of Albuquerque, N. Mex., USA and described in one or more of their U.S. Pat. Nos. 6,823,124; 6,251,488 and 6,811,744, and published U.S. Patent Applications 2004/0197493; 2004/0179808 and 2005/0046664, the disclosures of which are hereby incorporated by reference. Alternatively, any other suitable technique for applying a wet conductive material to surfaces  708  and  758  may be employed for defining the meander element. 
         [0068]    It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as modifications thereof which would occur to persons skilled in the art upon reading the foregoing specification and which are not in the prior art.