Patent ID: 6995729
Filing Date: 2006-02-07
Classification: A61B,H01Q

Abstract:
1. Apparatus for tracking an object, comprising: a power transmitter, adapted to radiate radio frequency (RF) energy toward the object in a first frequency band; one or more field generators, adapted to generate electromagnetic fields in a second frequency band in a vicinity of the object; a wireless transponder, adapted to be fixed to the object and comprising: an antenna assembly, comprising: a core; one or more power coils, wound around the core on respective power coil axes, including at least a first power coil having a first power coil axis; and one or more signal coils, wound around the core on respective signal coil axes, including at least a first signal coil wound so as to overlap the first power coil, the first signal coil having a first signal coil axis that is substantially parallel to the first power coil axis; power circuitry, coupled to the power coils so as to receive therefrom the RF energy in the first frequency band, and to rectify the RF energy so as to generate a direct current; and communication circuitry, powered by the direct current, and coupled to sense an alternating current flowing in the signal coils due to the electromagnetic fields in the second frequency band, and to transmit output signals indicative of the alternating current; and a signal receiver, adapted to receive the output signals and, responsively to the output signals, to determine coordinates of the object.