What makes up an RFID tag?
An RFID tag, or inlay as they are sometime referred to, is essentially a very small integrated circuit attached to an antenna (see right). Tags come in a variety of sizes and shapes, each unique to its own application. Some are battery powered (active), and some are battery-less (passive), meaning the reader antenna energizes the tag by radiating RF energy, which the tag then re-radiates back to the reader. Tags work at a wide variety of frequencies, depending on which standard the tag adheres to. Tags can come be read only, write once, or fully writable. The writeable memory can be as little as 64 bits for passive tags and up to as much as 32 kB for active tags. This memory can be read or written very quickly, in some cases as fast as 200 tags/sec! Having some memory gives your process the ability to read or write any data to it that you wish. This includes test data, location data, or even the new EPC codes.
