SAW sensors of organophosphorous compound with no humidity interference

Surface acoustic wave (SAW) sensors of organophosphorous compounds with no humidity interference are designed. ST-cutX quartz and fluoropolyol (FPOL) film in glassy-rubbery phase are the substrate and chemical interface of the sensors, respectively. The velocity shift and attenuation change increase with the thickness of FPOL. The velocity shift linearly varies with operating frequency when FPOL film is less than 0.02 μm. The operating frequency of the SAW sensor is chosen to be less than 180 MHz for oscillation of sensors. The operating frequency of the SAW sensor can be chosen carefully to induce negligible interference due to humidity. The optimum operating frequency with negligible humidity interference declines as the relative humidity increases in a common environment.