A Novel Wireless Thermal Convection Type Angular Accelerometer with Xenon Gas Filled in Hemispherical Chamber of Floating and Non-Floating Structures

Abstract

Five novel ideas are proposed in this paper to integrate an active RFID tag with thermal convection angular accelerometer on a flexible substrate, thus the device is a wireless sensor. The first idea is that this device is without any movable parts, so it is very reliable. The second one is that it is made on a flexible substrate, such as plastic or polyimide, the thermal conductivity of the flexible substrate of which is much lower than silicon, and thus it can save more power and very useful for mobile operation. The third idea is to apply xenon gas is in the chambers with floating and non-floating structures instead of CO 2 used in the traditional thermal convection accelerometer for heat conduction . Carbon dioxide may oxid ize the heater and thermal sensors, while the inert gas xenon does not. The fourth idea is to apply a hemispherical chamber; it is more streamline d with less drag effect. Thus it can ease the fluid flow and yield quicker response. The fifth idea is to integrate the angular accelerometer with an active RFID tag on the same substrate, thus the device becomes a more useful wireless sensor. From the results if one considers sensitivity as the first priority, then the non-floating structure is the choice ( 258°C/(rad/s 2 ) in average ). However , if the response speed is the top requirement, then the floating structure is better (60 μ s).