1. Technical Field of the Invention
The embodiments of the invention relate to radio frequency identification (RFID) devices and more particularly to transceivers that are utilized in RFID readers and RFID transponders.
2. Description of Related Art
Radio frequency identification (RFID) devices are being utilized in greater quantity in a multitude of applications. One of the more common areas for RFID implementation is in product identification, whether for inventory or for sale. The bar code scanner technology is slowly being replaced by RFID technology. In the simplest of applications, a passive RFID transponder, commonly called a tag or a card, is placed on an object that is to be identified. A RFID reader is then used to obtain information from the tag. The reader typically has a transceiver to transmit and receive signals, as well as being powered by a power source. The tag also has a transceiver to receive the signal from the reader and to transmit a response back to the reader. However, the tag is generally passive and powered by the induced electromagnetic field.
The reader is powered and generates a magnetic field from its antenna. When the reader and the tag are within close proximity of each other, the reader generated magnetic field is induced into the tag. The tag uses this coupled energy to power its circuitry. The reader transmits an interrogating signal to the tag, and in response the tag transmits a signal back to the reader. In the example stated above, the tag may be placed on an item and the response from the tag may be to simply identify the item. For these simple applications, the reader and the tag operate using a single protocol that is defined for the reader-tag combination. The transceiver circuitry, especially the circuitry in the tag, is made simple to keep the cost low. Standards bodies, such as International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC) set some of the standards and protocols for RFID communication.
However, as more complex applications are sought for the RFID technology, the existing RFID circuitry is limited in the amount and type of data that may be processed. For example, with certain communications security may be a paramount concern. If RFID devices are to be available for secure financial transactions or secure personal identification, more complex RFID devices may be needed to handle the type of data being transmitted. Furthermore, flexibility to allow reader-tag combinations to operate using different protocols may allow versatility in conducting a multitude of transactions. As more and more data are to be processed in RFID communications, it would also be advantageous to use a digital processor to process the data.
The described embodiments of the invention disclosed herein offer a RFID reader and RFID transponder which address some or all of these concerns, as well as others, to provide advantages over current RFID techniques.