| abstract |
(57) [Abstract] [Purpose] By using a SAW device for the sensor unit, the output frequency change caused by the selective adsorption reaction between the gas in the test gas and the gas adsorbent can be changed by using a bandpass filter, or The short-time Fourier transform or the wavelet transform is used for detection so that gas detection can be simplified. A surface acoustic wave device 10 includes a comb-shaped vibrating electrode 12 for exciting a surface acoustic wave on a piezoelectric substrate 11 for propagating the surface acoustic wave, and an elastic wave propagating from the electrode on the surface of the piezoelectric substrate. Comb-shaped receiving electrode 1 for receiving surface acoustic wave SAW 3, and at least a part of the surface of the piezoelectric substrate 11 between the electrodes 12 and 13 is covered with the gas adsorbent 14. The output of the receiving electrode 13 is processed by a band pass filter. When there are a plurality of surface acoustic wave devices, the outputs of the plurality of surface acoustic wave devices are combined into one and then processed by a band pass filter. |