A Wireless Rf and Dc Interface for a Mems-based Identification System

We describe a wireless system for actuating and detecting the motion of MHz-frequency, low dissipation MEMS resonators. The overall system is essentially a custom-designed RFID-like system, with the tags based upon unique MEMS chips as opposed to conventional RFID chips. The MEMS devices are vacuum encapsulated, rugged, CMOS-compatible, and are approximately 1mm-by-1mm-by-0.5mm. The system is passive in the sense that the DC voltage required to bias the MEMS resonators is scavenged from a UHF signal through the use of an on-tag RF-DC converter. The purpose of the system is to use the unique frequency spectrum of each MEMS-based chip to uniquely identify the chips.