Radio frequency identification (RFID) is a data collection technology that enables the storing and remote retrieval of data utilizing devices referred to as RFID tags, or transponders. An RFID transponder may comprise a silicon integrated circuit, or chip, and an antenna that enables the RFID transponder to receive and respond to radio frequency (RF) queries from an RFID transceiver, or reader. The RFID transponder may comprise memory, for example a random access memory (RAM) or an electrically erasable programmable read only memory (EEPROM), which enables storage of data. The data may comprise an electronic product code (EPC) that may be utilized to locate an item to which the RFID transponder is attached. For example, libraries may attach RFID transponders to books to enable the tracking of books that are checked out to library patrons. RFID transponders may be integrated into “smart cards” and/or into other electronic devices such as mobile phones. The RFID transponders may enable storage of account information that enables the holder of the smart card to purchase goods and services. The transponder may, for example, store a current balance that indicates a monetary value of goods and services that may be purchased with the transponder. The transponder holder may purchase goods and services by holding the transponder in the proximity of an RFID reader that retrieves account information from the smart card.
Designers of RFID transponders are challenged with the tasks of increasing the range at which the transponder can communicate with the reader and improving the energy efficiency due to the limited power available to the transponder, all while keeping the transponder extremely small and inexpensive.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.