Remote-powered high-performance strain sensing microsystem

This paper presents an RF remote-powered high-performance strain sensing microsystem. A MEMS capacitive strain sensor converts an input strain to a capacitance change, followed by low-noise integrated sensing electronics converting the capacitive signal to an output voltage with an overall sensitivity of 420 /spl mu/V//spl mu//spl epsiv/. An RF to DC converter based on inductive coupled coils converts a 50 MHz AC signal to a stable DC supply of 2.8 V with a current driving capability of 2 mA, sufficient to power the interface sensing electronics. The prototype microsystem achieves a minimum detectable strain of 0.09 HE over a 10 kHz bandwidth with a dynamic range of 81 dB. The sensing electronics consume 1.5 mA from a 2.8 V supply.