A Novel RFID-Based Thermal Convection Type Inclinometer with Non-Floating Structure and Hemi-Cylindrical Chamber

This research proposes a novel wireless RFID-based thermal convection inclinometer. Five new ideas are presented. The first one is to make it on a flexible substrate to save more energy than the traditional silicon. The second one is to integrate both an inclinometer and a wireless RFID antenna on the same substrate, such that it becomes a wireless sensor and very convenient for usage. The third idea is to apply the hemi-cylindrical chamber instead of the previous rectangular one, so the gas distribution is more streamlined to increase the sensitivity. The fourth idea is to use a non-floating structure instead of the floating one, thus it is more simple and low cost without making a cavity in the substrate. The fifth idea is to apply stacking material for the temperature sensors, so that the sensitivities are not only larger, but the curves are more linear. Three kinds of stacking height were studied, such as 1, 1.5 and 2mm. Moreover, three types of material with different thermal conductivity are also tested, such as alumina nitride (AlN), copper and silicon. If the chamber is filled with the traditional carbon dioxide, one can see the combination of AlN/2mm is better, and the maximal linear operating range and sensitivity are 75° and 0.107°C/Degree, respectively.