About Low cost test design of RFID / NFC tag
RFID technology and NFC technology based on RFID belong to the field of near-field communication, and have great application in the field of Internet of things. Both of them are based on the principle of electromagnetic induction, and use radio frequency signal to identify and communicate with the target. The reading and writing distance is an important index to evaluate the system, and the resonant frequency of the tag is the key parameter to affect this index.
After the passive tags of RFID and NFC are packaged, the resonant frequency can only be measured by non-contact method. The principle of non-contact measurement method is reflection measurement. By measuring the S11 of reflection parameters and observing the frequency value corresponding to the maximum negative peak value of S11, the resonant frequency of the tag can be obtained.