Selective Measurement of Water Content in Multivariable Biofuel Using Microstrip Split Ring Resonators

A bstract-Biofuel contamination by water becomes a very important issue, as biofuel usage is getting more popular. Therefore, real-time monitoring of water content in biofuel is very critical. This paper presents a split ring resonator-based sensor for measurement of the volumetric percentage of biofuel components. Since biofuel of interest, E85, consists of three components, ethanol, gasoline, and water, more measurement features are introduced in this work by employing frequency shifts of higher harmonics of a split ring resonator as well as the fundamental resonance. The overall precision in the volumetric measurement of all the components of completely dissolved mixtures is achieved with the total mean-square error of less than 0.85%.