rongly reflective to electromagnetic waves, so it will be accompanied by the signal weakening, the card distance will become closer, serious interference will appear card failure phenomenon. The current common solution is to put a layer of wave-absorbing material on the back of the electronic label.
Application of ferrite in NFC coils or antenna plates
Ultra-thin sintering NFC ferrite sheet brief introduction: 13.56MHZ antenna ferrite sheet / film is a high temperature sintering ferric oxide mat