Yen Jesse, Nussbaum Zoe
Biomedical Engineering, University of Southern California Los Angeles, USA.
Proc IEEE Ultrason Symp. 2020 Sep;2020. doi: 10.1109/ius46767.2020.9251816. Epub 2020 Nov 17.
Ultrasound technologies such as high-intensity focused ultrasound and acoustic radiation force imaging require advanced or sophisticated transducer designs. Oftentimes, these designs have transducer requirements of wide power ranges, high sensitivity, and broad bandwidth. However, it would often times be desirable to use the same transducer for both. The objective of this proof-of-concept study is to demonstrate the feasibility of using active damping of air-backed, narrowband transducers to achieve broadband capability. Active damping is accomplished through the use of arbitrary waveform generators to cancel subsequent oscillations beyond the initial excitation. A modified 1-D KLM model written in Matlab is used to guide the design of the waveforms. Optimization of the waveforms is applied to the KLM model using minimization function that minimizes ripple. In the model, - 3 dB transmitted bandwidth increased from 10% to 44% for 1.5-cycle excitation and 11.4% to 63.8% for 1-cycle excitation. Comparable increases in bandwidth were also observed experimentally.
诸如高强度聚焦超声和声学辐射力成像等超声技术需要先进或复杂的换能器设计。通常，这些设计对换能器有宽功率范围、高灵敏度和宽带宽的要求。然而，常常希望使用同一个换能器来实现这两种功能。本概念验证研究的目的是证明对空气背衬窄带换能器采用有源阻尼以实现宽带能力的可行性。有源阻尼是通过使用任意波形发生器来消除初始激励之后的后续振荡来实现的。用Matlab编写的改进的一维KLM模型用于指导波形设计。使用使纹波最小化的最小化函数将波形优化应用于KLM模型。在该模型中，对于1.5周期激励，-3dB发射带宽从10%增加到44%，对于1周期激励，从11.4%增加到63.8%。在实验中也观察到了类似的带宽增加。
