A 10-Mb/s Uplink Utilizing Rectifier Third-Order Intermodulation in a Miniature CMOS Tag

This letter introduces an inductive power transfer (IPT) uplink to a miniature CMOS tag. The transmitter (Tx) sends a two-tone waveform at 5.728/5.768 GHz to charge the tag and excites a third-order intermodulation frequency at 5.808 GHz from the tag rectifier, which is then modulated and returned to the reader receiver (Rx) via the same coupled coils used for the IPT. The Tx/Rx frequency separation, incorporating an appropriate duplexer, allows significant filtering on the Tx-to-Rx leakages. The achieved uplink data rate is 10 Mb/s.