The IoT is regarded as the third wave of the information industry after the computer and the Internet. In the process of its realization, it needs the cooperation of many high and new technologies. RFID, as one of the top ten important technologies in the 21 century, is an important cornerstone of the IoT. Combined with the Internet, communication, and other technologies, RFID can achieve global tracking and information sharing. RFID tags are the most critical and well-known part, which has gone deep into our daily life.

　　Nowadays, RFID tags appear in our vision in various forms, making our life more convenient and intelligent. RFID chips can be attached to almost anywhere: clothes, shoes, vehicles, containers, and even plants, animals, and humans (as implants). Microchips are even attached to insects. Today, let’s take a closer look at the RFID tag and unveil it.

　　Components of an RFID Tag

　　The RFID tag is one of the important components of the RFID system, which is mainly composed of three parts: chip, antenna, and substrate. The chip contains a logical control unit, memory, and transceiver for decoding, decrypting, and error checking. The antenna is used to receive RF signals from the reader or to transmit its identification information. The substrate is the carrier of the chip and the antenna, holding them together.

　　These three parts are indispensable. They determine and affect the performance and application environment of RFID tags. Different chip, antenna design, and substrates of different materials can be combined into RFID tags with different functional characteristics to meet a variety of requirements.

　　RFID Chip (IC)

　　The RFID chip, otherwise known as IC (short for Integrated Circuit), is usually designed and manufactured by semiconductor manufacturers. It is a small microprocessor, which has a logic unit that makes decisions and provides memory to store data.

　　Integrated circuits need the power to operate. This power can come from the battery on the tag (in the active tag) or the radio energy radiated by the interrogator’s antenna (in the passive tag). Part of the integrated circuit is used to control the power supply.

　　Integrated circuits can integrate a large number of micro transistors into a small chip. In 2006, the chip area ranged from a few square millimeters to 350 mm ², with up to a million transistors per mm ².

　　In recent years, with the development of semiconductor technology, integrated circuits are available in a smaller size, so that each chip can encapsulate more circuits. The number of transistors in integrated circuits doubles every 1.5 years. This increases the capacity per unit area, reducing costs, and increasing functionality. The tag IC is more efficient in power usage and requires less power to operate, increasing the reading range of the passive tag.