US Patent 7239243 RFID tag imager

In one embodiment, a system for obtaining an image of an RFID tag comprising a transponder and a tag antenna is provided, the system comprising: a plurality of inductors, each inductor being associated with a capacitor to form a resonant tank circuit, wherein each resonant tank circuit has a first resonant frequency in the presence of metal and a second resonant frequency in the absence of metal; a signal processor configured to determine a resonant frequency for each resonant tank circuit in the presence of the tag antenna; and a processor configured to compare the resonant frequency of each resonant tank circuit to the first and second resonant frequency to determine an image of the tag antenna.