The principle of 13.56M's high frequency card is electromagnetic induction technology. Through the alternating electromagnetic field, the passive card is provided with energy to realize the communication between the card and the reader.
The principle of UHF is electromagnetic propagation technology, similar to radar detection, sending out a section of electromagnetic wave, and then reading the information from the reflected electromagnetic wave.
UHF: the antenna is small, the transmission distance is far, the cost is high.
High frequency card: the antenna is large, the transmission distance is close, and the cost is low.