| 摘要 |
PURPOSE:To selectively detect a specific gas by providing a comb-like exciting electrode and a comb-like receiving electrode on a piezoelectric substrate, and applying a thin film including a host which has the gas to be detected as a quest between the two electrodes. CONSTITUTION:On a piezoelectric substrate 1, there are formed a comb-shaped exciting electrode 2 which excites a surface acoustic wave 3 and, a comb-shaped receiving electrode 4 which receives and converts the surface wave 3 to an electric signal. Moreover, a thin film 5 of gamma-cyclodextrin including a host which has a gas to be detected as a quest is applied to the surface of the substrate 1 between the electrodes 2 and 4. When an impulse voltage is impressed through an input terminal of the electrode 2 in the atmosphere, the surface wave 3 is excited by the electrode 2, spreading on the surface of the substrate 1, and converted to the electric energy by the electrode 4 and taken out as a high frequency output from an output terminal. A feedback amplifier circuit 8 is connected between the electrodes 2 and 4. Therefore, a signal received by the electrode 4 is amplified by the circuit 8 and fed back to the electrode 2. Thus, an oscillating circuit is constituted. |
