A plurality of one-quarter wavelength coplanar resonators 5a to 5d are formed in series on a dielectric substrate 1, and coplanar inputoutput terminal sections 4a and 4b are formed on the dielectric substrate at opposite ends of the series connection for coupling with resonators 5a and 5d, respectively. The vehicle comprises a temperature-responsive material to which a hydraulic fluid is associated. The zinc oxide film has a nano-sized thickness Y, corresponding to the surface acoustic wave device having the operational frequency f, satisfying the condition : Y=N\xd7Y0.