RFID system consists of two parts: read-write unit and electronic label . The reader sends electromagnetic pulses through the antenna, and the electronic tag receives these pulses and sends the stored information to the reader as a response. In fact, this is non-contact reading, writing or deleting of the data in the memory. The electronic tag includes RFID RF processing circuit and an ultra-thin antenna loop. The antenna is embedded in the tag with a plastic sheet. The most common tag is generally the size of a credit card. You can also design tags of different shapes and sizes according to different application requirements.
1. Inductive coupling
According to Faraday's law of electromagnetic induction, induced electromotive force is generated, and mutual inductance coupling is realized through space high-frequency alternating magnetic field, also known as magnetic coupling. One of the important and extensive applications is transformer. It is generally applicable to short-range RFID systems with low and high frequency operation. The operating frequencies are mainly 125 kHz, 225 kHz and 13.56 MHz. The recognition distance is less than 1m, and the typical action distance is 10-20cm.
This type is a radar principle model. According to the spatial propagation law of the electromagnetic wave, the electromagnetic wave reflection emitted simultaneously carries back the target information encountered. It is generally applicable to the long-distance RFID system with ultra-high frequency and microwave operation. The operating frequencies are mainly 433 MHz, 915 MHz, 2.45 GHz and 5.8 GHz. The recognition distance is greater than 1m, and the typical action distance is 3-10m.