13.56 MHz-RFID biosensor with on-chip spiral inductor

The radio frequency identification (RFID) technology has become very popular in many fields; anti-theft devices, smart card and library management. Recently, RFID biosensor chips have been reported, which integrates RFID and biosensor for inexpensive, small and subaqueous sensing system. However, RFID system typically uses external off-chip antennas, so that additional fabrication time and cost are required for the post process. This paper investigates the RFID biosensor with on-chip spiral inductor as the tag antenna. The process is simplified and cost reduced by integrating sensor chip and on-chip spiral inductor tag antenna that is fabricated with metal interconnect layer of standard complementary metal oxide semiconductor (CMOS) process. Finally, the RFID biosensor circuitary is proposed and the operation is confirmed by measurement. With such advances, low cost, low noise and simple measuring system can be expected.