Gas sensor array based on surface acoustic wave devices for rapid multi-detection

A surface acoustic wave (SAW) sensor array was developed for sensing amino gas. Poly-N-vinylpyrrolidone (PNVP) composite film as a sensitive interface material was deposited onto a 128° YX-LiNbO₃ substrate by the spin coating technique. Moreover, we have developed an improved portable electronic noise based on a 2×2 non-continuously working oscillators equipped with coated SAW sensor array. This gas sensor array system consists of SAW sensors, polymers with different polarity of function groups, signal readout electronics with quick connector, miniature sensing chamber made by acrylic, and aluminum plates. The adsorption of amino gas by the sensitive coating material modulates the phase velocity of the acoustic wave due to the mass loading and acoustoelectric effect. Thus, the targeted amino gas can be evaluated by recording the frequency shift of the SAW device. The fast response time (49 s) and recovery time (64 s), and larger frequency response of 800 Hz were observed from the fabricated SAW sensor under 150 ppm concentration of amino gas. The detection response and large frequency shift have been improved under current generation of SAW sensing array system.