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.