Methods of harmful effects limitation in SAW gas sensors

In this paper some problems concerning work stability of SAW NO/sub 2/ sensors employing copper phthalocyanine (PcCu) as the chemical interface and 128/spl deg/ YX lithium niobate as substrate are presented. The proposed sensing element consists of two delay lines: one of them is covered with a chemical coating (PcCu), the another is covered with Al and then PcCu. In this case a response of the sensor depends only on the conductivity changes of the PcCu layer during NO/sub 2/ exposure. Other effects are identical and therefore are cancelled.