声光器件的换能器带宽和镀层厚度的确定

根据压电换能器的Mason等效电路,就36°у切LN/PM声光器件和x切LN/TeO₂声光器件以及各种镀层材料和厚度计算了换能器损耗TL随规一化频率f/f₀的变化关系,由此可确定各镀层的厚度和器件的换能器带宽,还给出器件的电输入阻抗z_i在阻抗圆图上随f/f₀变化的轨迹,它可作为器件性能测试的理论依据。 关键词：

THE TRANSDUCER BANDWIDTH OF ACOUSTO-OPTIC DEVICES AND THE DETERMINATION OF THE LAYERS' THICKNESS

According to the Mason's equivalent circuit of piezoelectric transducer, we have calculated the functional relationship between transducer loss TL and normalized frequency f/f₀ for the 36°y-cut LN/PM and the x-cut LN/TeO₂ acousto-optic devices, with different layer materials and thickness. From these calculations, we can determine the thickness of the various layers rationally and the transducer bandwidth of the devices accurately. We give also the loci of the electric input- impedence Z_i with f/f₀ on the Smith chart, which can be used as theoretical foundation of quality tests for the devices.