Single chip interrogation system for a smart shoe wireless transponder

The objective of this paper is to design a wireless transponder for antenna-based sensors that can be used to simultaneously measure shear and pressure forces for diabetic foot diagnosis. The transponder will be placed on the top surface of a shoe and consists of sensor antennas and an identification system that transmits information to a receiver by modulating the signal reflected by the antennas sensor in the insole. The identification system includes an energy harvester, a crystal oscillator and a passive mixer. A single chip interrogation circuit has been designed in IBM130 nm CMOS technology to reduce size. The identification system including bond pads has a size of 1.2mm × 0.8mm.