SH-SAW liquid sensor for methanol concentration sensing

Operating Direct Methanol Fuel Cell (DMFC) at ideal condition, it is extremely important to measure fuel concentration and maintain it within a proper range. Fuel concentration measuring devices have been required. SH-SAW based methanol concentration sensor is one of promising candidate for DMFC. The objective of this study is to demonstrate fundamental proper ties of SH-SAW sensor system. The evaluated sensor is fabricated on a 36° Y-X LiTaO3 substrate and operates at 141MHz. The evaluations are conducted by measuring sample liquids which have different concentration, temperature, and conductivity. As results of the measurements, it is demonstrated that SH-SAW sensor has a sufficient concentration resolution (~0.1[wt%]), a temperature stability, and a conductivity sensing ability. These results show that SH-SAW based methanol concentration sensor is one of the most promising candidate of DMFC fuel control device.