NDIR Ethanol Gas Sensor with Two Elliptical Optical Structures

A unique elliptical structure is designed and prototyped for a nondispersive infrared (NDIR) ethanol gas sensor. A temperature compensation method is also derived for this structure, in this study. The initial output voltages of the ethanol, reference IR, and temperature sensors show linear temperature dependencies, and the variations are less than ±2mV, ±2mV, and ±2%, respectively. The estimated ethanol concentrations show high accuracies, with less than ±5% error, in the temperature range from 253K to 333K.