圆锥面PVDF聚焦换能器的非线性声场理论及实验研究

Theoretical and experimental study of the nonlinear ultrasonic field radiated from a conical focused PVDF transducer

圆锥面聚焦换能器可在超声成像中获得较好径向分辨率的同时提高探测深度.利用高斯声源函数叠加法来近似表示圆锥面聚焦声源的分布函数,结合近轴近似的KZK方程,得到了圆锥面聚焦换能器在损耗媒质中产生的基波、二次谐波声场的解析解.在实验上制作了PVDF圆锥面聚焦换能器,测量了圆锥面聚焦换能器的基波及二次谐波声场,实验结果和理论计算相符.

Conical transducer offers both good lateral resolution and large depth of detecting region for ultrasonic imaging. In this paper, the superposition of Gaussian beams is utilized to simulate the source distribution of the conical focused transducer. On the basis of the KZK equation, we obtain the analytical solution of the nonlinear sound field from the conical focused source. A conical focused PVDF transducer has been fabricated in our Lab and the sound field distributions of the fundamental and second harmonic components were experimentally measured. The measured results are in reasonably good agreement with the theoretical predictions.