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TopRfid System
An RFID system is contactless ID system using wireless communication. It is one of the technique used for the automatic identification. The automatic identification means to “automatically input bar-code, magnetic-card, RFID data, etc. with the use of hardware and software and not human intervention in order to recognize the content of the data”. Also, the biometrics, OCR, the machine vision are included in this technique.
An RFID system is made up of two components as shown in Fig. 1 (Finkenzeller, 2010). One is the RFID tag, which is located on the object to be identified, and another is the reader/writer. The RFID tag normally does not have the power supply to work, so the reader/writer not only exchange the data, but also supply the power and clock signal to the RFID tag. To do this, the RFID tag has an antenna or a coil as a coupling element for the communication, as shown in Fig. 2. Figure 3 shows a practical example of label type RFID tag using 13.56MHz. The small black box inside the coil in this figure is an IC chip. The RFID tag has various shapes, for example, label, card, coin, and stick.
Figure 1. Basic concept of RFID system
Figure 3. Example of RFID tag in practice use
RFID systems are classified according to the operating frequency, the physical coupling method and the communication range. For example, available operating frequency is 135 kHz, 13.56 MHz, 900 MHz, and 2.45GHz. The operating frequency is used properly depending on a purpose.