Low-Cost Inkjet Printed Passive Booster for Increasing the Magnetic Coupling in Proximity of Metal Object for NFC Systems

A passive fully inkjet-printed circuit on a plastic based flexible substrate for increasing the communication read range of an NFC based system is proposed. Two parallel coils resonating at 13.56 MHz are used for the improvement of coupling between the transmitter and receiver. The proposed system behaves like a lens by concentrating the absorbed magnetic energy from a wide area in a small focal region. Being a passive circuit, fully inkjet-printed and having only one discrete component made this circuit a very low-cost and tempting solution for improving the magnetic link between transmitter and receiver. Another advantage of this circuit is its operability in proximity of metal asset. Functionality of ordinary systems is severely affected by close metallic objects; hence, having a system that can operate in both conditions is favorable. The measured boosted power after the exploitation of the booster in proximity of the metal asset at 13.56 MHz is 15 dB.