Flexible cable and methods of manufacturing same

Abstract

A flexible cable for carrying RF signals and method of manufacturing same. The cable includes an elongate base substrate including a dielectric layer with an upper metal layer deposited on one side and a lower metal layer deposited on its other side. It further includes two parallel spaced-apart series of vias formed along the length of the base substrate, each via electrically interconnecting the upper metal layer and the lower metal layer, whereby a rectangular cross-sectional waveguide is provided between the upper metal layer, the lower metal layer and the two series of vias.

1 . A flexible cable comprising:
 a waveguide bounded, in a dielectric layer, by:
 a first metal layer deposited on a first side of the dielectric layer; 
 a second metal layer deposited on a second side of the dielectric layer; 
 a first plurality of closely spaced-apart vias, each via of the first plurality of vias electrically interconnecting the first metal layer and the second metal layer; and 
 a second plurality of closely spaced-apart vias, each via of the second plurality of vias electrically interconnecting the first metal layer and the second metal layer. 
   
     
     
         2 . The flexible cable of  claim 1  further comprising a stripline conductor running the length of the dielectric layer within the dielectric layer between the first metal layer and the second metal layer and between the two series of vias. 
     
     
         3 . The flexible cable of  claim 1 , wherein at least one of the first metal layer and second metal layer is etched to remove metal. 
     
     
         4 . The flexible cable of  claim 3 , wherein the at least one metal layer has a mesh pattern due to the etched removal of metal. 
     
     
         5 . The flexible cable of  claim 1  further comprising:
 an outer dielectric layer; and 
 an adhesive layer bonding the outer dielectric layer to the first metal layer. 
 
     
     
         6 . The flexible cable of  claim 5  further comprising a shielding film adhered to the outer dielectric layer. 
     
     
         7 . The flexible cable of  claim 1  further comprising:
 an outer dielectric layer; and 
 an adhesive layer bonding the outer dielectric layer to the second metal layer. 
 
     
     
         8 . The flexible cable of  claim 7  further comprising a shielding film adhered to the outer dielectric layer. 
     
     
         9 . The flexible cable of  claim 1  further comprising a shielding film adhered to one of the first metal layer and the second metal layer. 
     
     
         10 . The flexible cable of  claim 9 , wherein the shielding film comprises an adhesive layer, a metallic layer and an insulation layer. 
     
     
         11 . The flexible cable of  claim 1 , wherein the dielectric layer comprises polyimide. 
     
     
         12 . The flexible cable of  claim 1 , wherein the first metal layer and second metal layer comprise copper layers. 
     
     
         13 . A method of manufacturing a flexible cable, the method comprising forming a waveguide by:
 depositing a first metal layer on a first side of a dielectric layer;   depositing a second metal layer on a second side of the dielectric layer;   forming a first plurality of closely spaced-apart vias through the dielectric layer, each via of the first plurality of vias electrically interconnecting the first metal layer and the second metal layer; and   forming a second plurality of closely spaced-apart vias through the dielectric layer, each via of the first plurality of vias electrically interconnecting the first metal layer and the second metal layer.   
     
     
         14 . The method of  claim 13  further comprising etching at least one of the first metal layer and the second metal layer to remove metal. 
     
     
         15 . The method of  claim 14 , wherein the etching includes removing a pattern of metal to create a mesh. 
     
     
         16 . The method of  claim 13  further comprising:
 applying an adhesive layer to a given metal layer, wherein the given metal layer is either the first metal layer or the second metal layer; and 
 bonding an outer dielectric layer to the adhesive layer. 
 
     
     
         17 . The method of  claim 16  further comprising adhering a shielding film to the outer dielectric layer. 
     
     
         18 . The method of  claim 13  further comprising adhering a shielding film to one of the first metal layer and the second metal layer. 
     
     
         19 . The method of  claim 13 , wherein the dielectric layer comprises polyimide. 
     
     
         20 . The method of  claim 13 , wherein the first metal layer and second metal layer comprise copper layers.