RFID (Radio Frequency Identification) technology is a technology that uses radio waves to recognize information from a long distance. Here, RFID tags (hereinafter referred to as tags) and RFID readers (hereinafter referred to as readers) are required. A tag consists of an antenna and an integrated circuit, which records information in an integrated circuit and transmits information to the reader via an antenna. This information is used to identify the tagged object. In a nutshell, it is similar to a barcode. RFID is different from barcode systems in that it uses radio waves instead of reading them using light. So it does not work at short distances like a barcode reader, it can read tags from a long distance, and even receive information through objects in between.
RFID can be classified as power used. The RFID that reads and communicates information of the chip only by the power of the reader is called passive RFID. Semi-passive RFID refers to the use of the power of a chip to read information from a chip, and the power of a reader to communicate with a tag because the tag is embedded in the tag. Finally, active RFID uses the power of the tag to both read information from the chip and communicate it.
RFID is divided into frequency of radio waves used for communication instead of power. Low-frequency RFID is called LFID (Low-Frequency IDentification), and it uses 120 ~ 140 kilohertz (kHz) radio waves. The High-Frequency IDentification (HFID) uses 13.56 megahertz (Mhz) and the higher frequency UHFID (UltraHigh-Frequency IDentification) uses the 868 ~ 956 megahertz band.