Application of different spatial sampling patterns for sparse array transducer design

In the last few years, the efforts of many researchers have been focused on developing 3D real-time scanners. The use of 2D phased-array transducers makes it possible to steer the ultrasonic beam in all directions in the scanned volume. An unacceptably large amount of transducer channels (more than 4,000) must be used, if the conventional phased array transducers are extrapolated to the 2D case. To decrease the number of channels, sparse arrays with different aperture apodization functions in transmit and receive apertures have to be designed. The design is usually carried out in 1D, and then transferred to a 2D rectangular grid. In this paper, five different 2D array transducers have been considered and their performance was compared with respect to spatial and contrast resolution. An optimization of the element placement along the diagonals using vernier arrays is suggested. The simulation results of the ultrasound fields show a decrease in the grating-lobe level of 10 dB for the diagonally optimized 2D array transducers compared to the previously designed 2D arrays which did not consider the diagonals.     

超宽带红外声光可调滤光器的设计

根据声束可逆原理,通过在声光互作用介质上相向设置两个具有不同谐振频率的换能器的方法设计出了超宽带的声光滤光器。该器件的带宽是常规器件的两倍。同时,该设计采用了声谐振结构。它可以大幅度地降低驱动源的功率。对于工作在红外波段的声光器件,这一点具有十分重要的意义。     

Double-layered piezo-thermoelastic hollow cylinder under some coupled loadings

In the present paper, a long thick-walled piezo-thermoelastic hollow cylinder with double layers is studied. The effects of temperature on the performance of the cylinder are obtained. Based on the theory of elasticity, the exact solutions of the cylinder under some coupled loadings are found. In the present paper, differences of a piezoelectric parameter between the two layers is taken into account. For comparison, numerical results have been carried out for both double-layered and graded cylinders. At the end of the present paper some discussions are addressed.     

有限非均匀空腔障板对换能器指向性的影响

声障板可以改善换能器的灵敏度和指向性,是换能器及基阵设计中必不可少的声学结构。本文建立了有限空腔障板和非均匀空腔障板的模型。利用射线声学的理论,研究了以上两种障板对换能器指向性的影响,结果表明障板的边缘和障板的厚度变化都会影响换能器的指向性。文章最后给出了部分实验结果,理论结果与实验结果基本相符。     

包含外壳磁阻的微型平衡电枢换能器仿真模型的阻抗和振动分析

现有的“E”型平衡电枢等效磁路模型仿真研究通常不考虑金属外壳磁阻带来的影响。为了解决平衡电枢换能器中因金属外壳和平衡电枢紧密接触带来的非线性磁阻问题，在现有的平衡电枢换能器等效磁路模型上加入了外壳磁阻影响。分析等效磁路模型磁通部分和力学部分的状态空间方程在不同参数条件下的仿真结果，总结不同参数对该模型阻抗和振膜位移的影响情况。通过仿真对比，外壳磁阻对平衡电枢换能器位移频率响应曲线的影响为1～3 dB。对于组装后包含金属外壳的平衡电枢耳机、助听器产品降低频率响应曲线偏差具有一定的指导意义。