中文摘要：

利用空气中超声波非线性传播效应制作一种可产生高指向性可听声的新型声束扬声器。以聚偏氟乙烯（PVDF）膜作为声频定向换能器的发声部件，根据惠更斯原理分析、讨论了声束扬声器单个换能器及换能器阵列的指向性，并指出当无法使点声源间的间距小于或等于声波波长的1／2时，可以通过增加点声源的个数来获得高指向性声波，使旁瓣的幅值得到有效抑制。

英文摘要：

A novel audio beam loudspeaker is fabricated by utilizing the nonlinear propagation effects of ultrasonic in the air to generate audible high directivity sound. The polyvinylidene fluoride（PVDF）film is used to be the acoustic generator of its transducer. The directivity of single transducer and transducer array are discussed according to Huygen＇s principle. A method is proposed by increasing the quantity of spot sound sources to generate high directivity sound wave, and to suppress the amplitude of sidelobes when it is impossible to make the distance between spot sound sources less than or equal to a half of the wavelength of ultrasonic sound wave.