An apparatus and method are described for a radio frequency document
control system that enables the location of documents, such as office
files, to be automatically and rapidly identified. A host transceiver,
controlled via a PC, transmits a coded RF signal, at a first frequency, to
individually addressable, low cost, local exciters/transceivers located on
shelves and/or in drawers. The local exciters, which may be sequentially
addressed, retransmit the coded RF signal at a second frequency via an
antenna. A passive radio frequency identification tag, containing the same
code as that transmitted by the local exciter and attached to a document,
such as a file folder, when in the vicinity of the antenna of the local
exciter, is energized by the RF field and modulates the second frequency
signal from the local exciter. The second frequency signal modulated by
the energized tag is then directly received by the host transceiver. A PC,
coupled to the host transceiver, enables the system to automatically and
rapidly identify, down to a specific shelf or drawer, the location of
tagged documents in an office environment.