The classification of RFID systems is best summarized by the figure below. The major frequency bands in which most RFID systems operate, along with some of their respective characteristics and applications are summarized in the table below. Active tags have an on-board power source, such as a battery. The advantage of active tags is that they reduce the power requirements of the reader, and they can transmit their information over relatively far distances. The disadavantages are that they have a limited operating life, can only be used in certain environments, and are more expensive than passive devices.
Passive tags operate without an on-board power source.
They obtain their operating power from energy generated by the reader. They are smaller, lighter, and less expensive than active tags. Furthermore, passive tags have a virtually unlimited life time. Some disadvantages of passive tags are that they have a shorter read range than active tags, and require a much higher-powered reader. We are currently compiling a list of RFID manufacturers , along with a summary of the types of tagging systems they produce.