Mobile device with coupling area enhancement

Abstract

A coupling area enhancement device includes a small coil and a large coil on opposing sides of a sheet of electromagnetic interference (EMI) absorptive material. The coupling area enhancement device may include one or more holes and may include adhesive material and sticker covers. Placement of the coupling area enhancement device may be accomplished by sticking the small coil to a host device near a contactless antenna. The large coil may also be stuck to a battery cover.

What is claimed is: 
     
         1 . A mobile device comprising:
 a communications chip;   a mobile device coil coupled to the communications chip;   a sheet of electromagnetic interference (EMI) absorptive material;   a first coil on a first side of the sheet of EMI absorptive material; and   a second coil on a second side of the sheet of EMI absorptive material, wherein the second coil is coupled to the first coil, and the second coil is larger than the first coil;   wherein the sheet of EMI absorptive material is positioned to align the first coil with the mobile device coil.   
     
     
         2 . The mobile device of  claim 1  wherein the first coil is electrically coupled to the second coil. 
     
     
         3 . The mobile device of  claim 1  wherein the first coil is magnetically coupled to the second coil. 
     
     
         4 . The mobile device of  claim 1  wherein the sheet of EMI absorptive material includes at least one hole. 
     
     
         5 . The mobile device of  claim 1  wherein the first coil is located at one corner of the sheet of EMI absorptive material. 
     
     
         6 . The mobile device of  claim 1  wherein the first coil is located at one edge of the sheet of EMI absorptive material. 
     
     
         7 . The mobile device of  claim 1  further comprising a plurality of small coils on the first side. 
     
     
         8 . The mobile device of  claim 1  further comprising adhesive material on the first side of the sheet of EMI absorptive material. 
     
     
         9 . The mobile device of  claim 8  wherein the adhesive material is placed to adhere a portion of the sheet of EMI absorptive material corresponding to the first coil to a coupling area of the mobile device coil. 
     
     
         10 . The mobile device of  claim 9  further comprising additional adhesive material on the second side of the sheet of EMI absorptive material, wherein an area of the additional adhesive material on the second side is larger than an area of the adhesive material on the first side. 
     
     
         11 . A mobile device comprising:
 a communications chip;   a mobile device coil coupled to the communications chip;   a flexible substrate with electromagnetic interference (EMI) absorptive qualities;   a first coil on a first side of the flexible substrate; and   a second coil on the first side of the flexible substrate, wherein the second coil is electrically coupled to the first coil, and the second coil is larger than the first coil, the flexible substrate being folded such that the first and second coils appear to be on opposing sides;   wherein the flexible substrate is positioned to align the first coil with the mobile device coil.   
     
     
         12 . The mobile device of  claim 11  wherein mobile device comprises a mobile phone. 
     
     
         13 . The mobile device of  claim 11  further comprising adhesive material formed over the first coil to aid in locating the first coil over the mobile device coil. 
     
     
         14 . The mobile device of  claim 13  further comprising additional adhesive material formed over the second coil to aid in securing the coupling area enhancement device. 
     
     
         15 . The mobile device of  claim 11  wherein the flexible substrate has EMI absorptive qualities at substantially 13.56 MHz. 
     
     
         16 . A mobile device comprising:
 a contactless device with a loop antenna; and   a coupling area enhancement device having a first coil placed to couple to the loop antenna, a second coil larger than the first coil and coupled to the first coil, and a sheet of electromagnetic interference (EMI) absorptive material between the first and second coils.   
     
     
         17 . The mobile device of  claim 16  wherein the first coil is electrically coupled to the second coil. 
     
     
         18 . The mobile device of  claim 16  wherein the first coil is magnetically coupled to the second coil. 
     
     
         19 . The mobile device of  claim 16  further comprising a memory card, wherein the loop antenna is on the memory card. 
     
     
         20 . The mobile device of  claim 16  wherein the apparatus comprises a mobile phone.