Maybe something like this? I am just speculating.
https://www.google.com/patents/US20...a=X&ei=OA9JVI2xNIi2yASn24CoAg&ved=0CB0Q6AEwAA
"To accommodate near field communications within the potentially tight confines of device housing 12, antenna structures 40 may be shared between non-near-field communications circuitry 44 and near field communications circuitry 42. When, for example, it is desired to transmit and receive cellular telephone signals or other non-near-field communications, antenna structures 40 may be used by transceiver circuitry 38. When it is desired to transmit and receive near field communications signals, antenna structures 40 may be used to near field communications circuitry 42."