一种“闪烁型”IDT阵列声束偏转器
BEAM DEFLECTOR OF SAW FORMED BY AN IDT ARRAY OF "FLASH GRATING" TYPE
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摘要: 本文提出了一种类比于光学中“闪烁光栅”的声表面波叉指换能器的陈列结构。讨论了由该阵列激励的一级声束(主偏转声束)的相对强度与阵列诸参数的关系。讨论了该声束的相对强度随声频而变化的规律(频率响应)。理论分析与实验结果表明:对本文所述的具体阵列结构说来,主偏转声束的相对强度,在声频变化一个倍频程范围内,达65%以上,而其起伏小于3dB。本文所得到的一些基本规律,适用于阶梯形叉指换能器阵列所构成的声束偏转结构。Abstract: A configuration of surface acoustic wave beam deflector performed with a distributed array of IDTs is investigated. This configuration corresponds to the flash grating in optics. The relations of the deflection angle and of the relative intensity for the main deflection order (first order in the spatial frequency spectrum of the IDT array with the parameters of the array are discussed. It is demonstrated by analyses and experiments that in the frequency range of one octave, the relative intensity of the main deflection beam is more than 65%, and the ripple in this frequency range is less than 3dB. The essential results obtained in this letter are applicable to the SAW beam deflection configuration with a stepped IDT array.