RFID-Based Thermal Convection Non-Floating Type Accelerometer with Stacking Material for Heater and Thermal Sensors

Abstract

This research proposes a wireless non-floating type thermal convection accelerometer, in which the heaters and the thermal sensors were made on the surface of a flexible substrate with a stacking material (such as aluminum nitride with thickness 1mm), this new device is different from those of the traditional floating structures with a grooved chamber in the silicon substrate. Thus one can integrate both a thermal convection accelerometer and a wireless RFID antenna on the same substrate, and this accelerometer is a wireless one and very convenient for fabrication and usage. Besides, the filling gas was changed as xenon to avoid the oxidizing effect that will be produced by the previously used CO2or air. Thus not only the reliability but the life cycle of the heater can be increased. The performances by using the traditional rectangular chamber for either xenon or CO2without stacking material had nonlinear effects. But the cases by using a stacking layer and xenon gas are always better. Comparisons with the previous accelerometer with rectangular chamber, stacking material and filled by CO2are also made (with sensitivity 0.182°C/G), the sensitivity for the new one with hemi-cylindrical chamber, xenon gas and stacking material is better (0.227°C/G) and without nonlinear effect in larger accelerations. The new device can be used in the applications of air bags and munition industry.