A CMOS 2.45-GHz radio frequency identification tag IC with read/write memory

A 2.45-GHz RFID tag chip was designed on standard 0.25- /spl mu/m CMOS process. Using only MOS devices, the low-Vt rectifier circuit produces 100 /spl mu/W of power with 2 dBm input. The tag IC with bidirectional communication and anti-collision features can be read from a distance of up to 15 cm under a reader power of 250 mW. The die area of 0.79 mm/sup 2/ includes a 128-bit rewritable non-volatile memory.