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利用声表面波(SAW)延迟线振荡器能制成一个位移传感器。这种延迟线振荡器具有两块铌酸锂(LiNbO_3)板,每一块板的表面带有一个叉指式换能器(1DT),把两块板的传播表面的一部分相互搭接在一起。在声表面波传感器中,振荡频率取决于声表面波元件的传播途径长度,这个长度通过移动振荡器的两块铌酸锂板中的一块板来改变。本文所说的声表面波位移传感器具有很高的灵敏彦,达300Hz/μm 和1.0kHz/μm。它是通过在 Y—X 两块铌酸锂板的表面上分别用6.5对(间距为0.55mm)和5对(间距为0.4mm)的叉指式换能器来实现的。声表面波延迟线振荡器的模态转换在某个给定的传播途径长度上出现,可用频谱分析仪观察。
A surface acoustic wave (SAW) delay line oscillator can be used to create a displacement sensor. This delay line oscillator has two LiNbO_3 plates, each with an interdigital transducer (1DT) on the surface, and a portion of the propagation surfaces of the two plates overlapping each other. In SAW sensors, the oscillation frequency depends on the propagation path length of the SAW element, which length is changed by moving one of the two lithium niobate plates of the oscillator. SAW displacement sensor described in this article has a very high sensitivity Yan, up to 300Hz / μm and 1.0kHz / μm. It is achieved by using 6.5 pairs (0.55 mm pitch) and 5 pairs (pitch 0.4 mm) of interdigital transducers on the surface of two Y-X lithium niobate plates, respectively. The SAW delay line oscillator mode transition occurs at a given propagation path length and can be observed with a spectrum analyzer.