RFID technology is called electronic label, and RFID system is mainly composed of three parts Among the many wireless communication technologies nowadays, some of them are well-known, and we all know in which fields these technologies are used, and there are also some technologies that are much less famous. For example, RFID technology, RFID (Radio Frequency Identification) technology is an automatic identification technology that began to emerge in the 1990s. However, RFID technology is regarded by many researchers as one of the most promising information technologies in the 21st century. Let us understand RFID technology below.1. Definition of RFID technology RFID technology, also known as electronic tag, is a short-range wireless communication technology that can identify specific targets and read and write related data through radio signals without the need to establish mechanical or optical contact between the identification system and specific targets. Therefore, it is a A non-contact automatic identification technology.2. RFID system compositionThe RFID system mainly consists of three parts: tag, reader and antenna. Generally, the data information collected by the reader is transmitted to the background system for processing.(1) Tag: The tag is composed of coupling elements and chips. Each electronic tag has a unique electronic code, which is attached to the object to identify the target object; each tag has a globally unique ID number-UID (user identification ), it is stored in the ROM when making the tag chip and cannot be modified. It has a very important impact on the development of the Internet of Things.(2) Reader: The reader is a device that reads or writes tag information, and it can be designed as a handheld or fixed type. The tags are identified, read, and written. Generally, the collected data information is transmitted to the background system, and the background system processes the data information.(3) Antenna: The antenna is used to transmit radio frequency signals between the tag and the reader. The antenna in the radio frequency circuit is the bridge between the reader and the electronic tag. The radio frequency signal energy sent by the reader is radiated to the space in the form of electromagnetic waves through the antenna. When the antenna of the electronic tag enters the space, it receives electromagnetic wave energy, but only Receive a small part of it.There are two antenna coupling methods between the reader and the electronic tag: one is inductive coupling, which is suitable for low-frequency radio frequency identification systems; the other is backscatter coupling mode, which is suitable for ultra-high frequency radio frequency identification system applications . The antenna can be regarded as the air interface between the reader and the electronic tag, and it is a very important part of the RFID system.