Electronic Device Antenna Structures With Ferrite Layers

Abstract

Electronic devices may be provided that have antenna traces. The antenna traces may be configured to form an inductive loop that serves as a near field communications antenna. A layer of ferrite may be provided to reduce interference between the antenna and internal device components. The layer of ferrite and the antenna traces may be deposited on a common substrate such as a layer of polymer or a dielectric electronic device housing. A protective layer of polymer may be used to form a coating on the layer of ferrite. Ferrite may be formed on the same side of a substrate as the antenna traces or may be formed on an opposing side of the substrate.

What is claimed is: 
     
         1 . An electronic device, comprising:
 a housing; and   antenna structures mounted in the housing, wherein the antenna structures include:
 a layer of polymer, 
 metal antenna traces formed on the layer of polymer, and 
 a ferrite layer formed on the layer of polymer that covers the antenna traces. 
   
     
     
         2 . The electronic device defined in  claim 1  wherein the ferrite layer comprises a polymer ferrite layer. 
     
     
         3 . The electronic device defined in  claim 1  wherein the metal antenna traces are configured to form an inductive loop for a near field communications antenna. 
     
     
         4 . The electronic device defined in  claim 1  further comprising a layer of adhesive between the layer of polymer and the housing. 
     
     
         5 . The electronic device defined in  claim 1  further comprising an additional polymer layer, wherein the additional polymer layer is formed on the ferrite layer. 
     
     
         6 . The electronic device defined in  claim 1  wherein the ferrite layer comprises a ceramic ferrite. 
     
     
         7 . The electronic device defined in  claim 6  further comprising an additional polymer layer, wherein the additional polymer layer is formed on the ceramic ferrite layer. 
     
     
         8 . An electronic device, comprising:
 a housing; and   antenna structures mounted in the housing, wherein the antenna structures include:
 a layer of polymer, 
 a ferrite layer formed on the layer of polymer, and 
 metal antenna traces formed on the layer of ferrite, wherein the ferrite layer is interposed between the metal antenna traces and the layer of polymer. 
   
     
     
         9 . The electronic device defined in  claim 8  wherein the ferrite layer comprises a polymer ferrite layer. 
     
     
         10 . The electronic device defined in  claim 8  wherein the metal antenna traces are configured to form an inductive loop for a near field communications antenna. 
     
     
         11 . The electronic device defined in  claim 8  further comprising a layer of adhesive interposed between the ferrite layer and the housing, wherein the metal antenna traces are interposed between the ferrite layer and the layer of adhesive. 
     
     
         12 . A method of forming antenna structures, comprising:
 depositing a layer of ferrite on a first surface of a substrate that has an opposing second surface; and   forming patterned antenna traces on the second surface of the substrate.   
     
     
         13 . The method defined in  claim 12  wherein forming the patterned antenna traces comprises forming an inductive loop for a near field communications antenna. 
     
     
         14 . The method defined in  claim 12  wherein forming the patterned antenna traces comprises forming the patterned antenna traces using laser direct structuring equipment. 
     
     
         15 . A method of forming antenna structures, comprising:
 forming patterned antenna traces on a substrate that has an opposing first and second surfaces; and   depositing a layer of ferrite on the first surface.   
     
     
         16 . The method defined in  claim 15  wherein forming the patterned antenna traces comprises forming an inductive loop for a near field communications antenna. 
     
     
         17 . The method defined in  claim 16  wherein forming the patterned antenna traces comprises forming the patterned antenna traces on the first surface. 
     
     
         18 . The method defined in  claim 17  wherein forming the patterned antenna traces comprises forming the patterned antenna traces using laser direct structuring equipment. 
     
     
         19 . The method defined in  claim 16  wherein forming the patterned antenna traces comprises forming the patterned antenna traces on the second surface. 
     
     
         20 . The method defined in  claim 19  wherein forming the patterned antenna traces comprises forming the patterned antenna traces using laser direct structuring equipment.