Wireless communication accessory for a mobile device

Abstract

A mobile device peripheral that incorporates a repeater antenna inside of a protective case for a mobile device to extend the range of short-range communications while minimizing interference caused by the thickness or materials of the protective case. The repeater antenna can be capable of receiving a wireless signal from an antenna in the mobile device and transmitting the same signal or an amplified version of the same signal. The repeater antenna can be capable of receiving a wireless signal from an external antenna and transmitting the same signal or an amplified version of the same signal to the mobile device. The mobile device peripheral can also include a battery that provides additional power the mobile device. Without a repeater antenna, the materials and/or thickness of the additional battery and/or the case can partially or completely block a short-range, low-frequency, or low-power communication signal such as Near Field Communication (NFC).

What is claimed is: 
     
         1 . A method of transmitting a near field communication (NFC) signal from a mobile electronic device that is at least partially enclosed by a protective case, the method comprising:
 providing a mobile electronic device that is at least partially enclosed by a protective case;
 wherein the mobile electronic device comprises a battery and an antenna configured to transmit near field communication (NFC) signals; 
 wherein the protective case comprises a supplemental battery configured to charge the mobile electronic device; 
 wherein the protective case comprises a repeater antenna that includes a first antenna disposed on a first side of the supplemental battery, a second antenna disposed on a second side of the supplemental battery, and an electrical connection that electrically couples the first antenna to the second antenna; 
   transmitting an NFC signal from the antenna of the mobile electronic device, wherein the supplemental battery is positioned to block or otherwise impede the NFC signal;   receiving the NFC signal by the first antenna of the repeater antenna;   relaying the NFC signal from the first antenna of the repeater antenna to the second antenna of the repeater antenna via the electrical connection; and   re-transmitting the NFC signal from the second antenna of the repeater antenna.   
     
     
         2 . The method of  claim 1 , further comprising
 receiving an incoming NFC signal by the second antenna of the repeater antenna;   relaying the incoming NFC signal from the second antenna of the repeater antenna to the first antenna of the repeater antenna via the electrical connection;   re-transmitting the NFC signal from the first antenna of the repeater antenna; and   receiving the re-transmitted signal by the antenna of the mobile electronic device.   
     
     
         3 . A protective case for a mobile electronic device, the protective case comprising:
 a housing that includes a cavity configured to at least partially enclose a mobile electronic device that has an antenna for transmitting and receiving signals from a rear of the mobile electronic device, the housing comprising a back plane configured to be disposed rearward of the mobile electronic device;   a battery inside the housing such that the battery is configured to be disposed rearward of the mobile electronic device;   a first antenna disposed on a first side of the battery facing forward and configured to receive signals from, and transmit signals to, the antenna of the mobile electronic device;   a second antenna disposed on a second side of the battery facing rearward; and   an electrical connection that electrically couples the first antenna to the second antenna, wherein the electrical connection is configured to communicate signals between the first antenna and the second antenna;   wherein the first antenna is configured to re-transmit signals received by the second antenna, and wherein the second antenna is configured to re-transmit signals received by the first antenna.   
     
     
         4 . The protective case of  claim 3 , further comprising a mobile electronic device at least partially enclosed by the housing of the protective case. 
     
     
         5 . The protective case of  claim 4 , wherein the mobile electronic device comprises:
 an antenna for transmitting and receiving signals from a rear of the mobile electronic device;   a battery; and   a device interface;   wherein the protective case comprises an interface configured to couple to the device interface to provide an electrical connection for the battery of the protective case to charge the mobile electronic device.   
     
     
         6 . The protective case of  claim 4 , wherein the mobile electronic device comprises a mobile phone or a tablet computer. 
     
     
         7 . The protective case of  claim 3 , further comprising an interface configured to couple to a device interface on the mobile electronic device to provide an electrical connection for the battery of the protective case to charge the mobile electronic device. 
     
     
         8 . The protective case of  claim 3 , wherein the first antenna and the second antenna are formed on a flexible printed circuit board. 
     
     
         9 . The protective case of  claim 3 , further comprising:
 a first ferrite layer disposed between the battery and the first antenna; and   a second ferrite layer disposed between the battery and the second antenna.   
     
     
         10 . The protective case of  claim 3 , wherein the first antenna and the second antenna are configured to receive and transits near field communication (NFC) signals. 
     
     
         11 . A case for a mobile electronic device, the case comprising:
 a housing configured to removably couple to a mobile electronic device;   a first antenna inside the housing; and   a second antenna inside the housing and spaced apart from the first antenna; and   a communication link between the first antenna and the second antenna;   wherein the first antenna is configured to emit a signal that is based at least in part on a signal received by the second antenna, or wherein the second antenna is configured to emit a signal that is based at least in part on a signal received by the first antenna.   
     
     
         12 . The case of  claim 11 , further comprising a battery disposed between the first antenna and the second antenna. 
     
     
         13 . The case of  claim 12 , further comprising an interface configured to couple to a device interface on the mobile electronic device to provide an electrical connection for the battery of the protective case to charge the mobile electronic device. 
     
     
         14 . The case of  claim 11 , further comprising one or more insulating layers disposed between the first antenna and the second antenna. 
     
     
         15 . The case of  claim 11 , further comprising one or more ferrite layers disposed between the first antenna and the second antenna. 
     
     
         16 . The case of  claim 11 , further comprising:
 one or more insulating layers disposed between the first antenna and the second antenna;   a first ferrite layer disposed between the one or more insulating layers and the first antenna; and   a second ferrite layer disposed between the one or more insulation layers and the second antenna.   
     
     
         17 . The case of  claim 16 , further comprising a battery disposed between the first antenna and the second antenna, wherein the one or more insulation layers comprises a first insulating layer disposed between the battery and the first ferrite layer and a second insulating layer disposed between the battery and the second ferrite layer. 
     
     
         18 . The case of  claim 11 , wherein the first antenna and the second antenna are positioned such that the first antenna is configured to be closer than the second antenna to the mobile electronic device. 
     
     
         19 . The case of  claim 11 , further comprising a battery configured to amplify the signal emitted by the first antenna or the signal emitted by the second antenna. 
     
     
         20 . The case of  claim 11 , further comprising:
 a third antenna; and   a communication link between the first antenna and the third antenna;   wherein the second antenna is configured to emit a signal that is based at least in part on a signal received by the first antenna, and wherein the third antenna is configured to emit a signal that is based at least in part on a signal received by the first antenna.