Near-field communication system in which power transfer is interleaved in time with data transfer

摘要

The present invention is concerned with power transfer between a Near-Field Communication (NFC) interrogator and a passive NFC tag. The power is transferred in a first time period 602 and data communications take place in a second time period 600. This allows data to be transmitted at a high data rate using phase shift keying (PSK), frequency shift keying (FSK) or quadrature amplitude modulation (QAM). Preferably, power transmission periods alternate with communication periods in time. The interrogator preferably uses a higher Q-factor antenna for power transmission than for data transmission. This may be achieved by periodically switching between different antennas or by periodically adjusting an impedance of the antenna system.