Impedance matching network for high frequency ultrasonic transducer for cellular applications.
Impedance matching network for high frequency ultrasonic transducer for cellular applications.
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DOI：
10.1016/j.ultras.2015.09.016
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发表时间：
2016-02
期刊：
影响因子：
4.2
通讯作者：
Shung KK
中科院分区：
文献类型：
--
作者：
Kim MG;Yoon S;Kim HH;Shung KK
本文提出了一种基于阻抗分析的高频大口径超声换能器阻抗匹配网络（IMN）的设计方法。的主要目标是最大限度地提高能量传输从激励源的超声波换能器的细胞操作，并实现低输入参数的超声波换能器的安全操作，因为在高频超声波换能器的压电材料是很容易断裂，由于它是非常薄的。对厚度为15 μm的钛酸锂单晶制成的孔径分别为4.3mm（fnumber = 1.23）和2.6mm（fnumber = 0.75）的两种超声换能器进行了测试。选择L型IMN用于超声换能器的高灵敏度和紧凑设计。目标中心频率被选择为阻抗分析中的导纳（θ Y）和相位角（θz）分别为最大值和零的频率。选择参考中心频率和参考回波幅度作为无IMN超声换能器的中心频率和回波幅度，通过脉冲回波测试测量。IMN的初始元件值和拓扑结构使用史密斯圆图确定，并分析脉冲回波测试，以验证有和没有IMN的超声换能器的性能。在改变IMN的组件值和拓扑结构与具有IMN的超声换能器的脉冲回波测量之间的几次迭代之后，当从脉冲回波测试测量的中心频率与目标频率相当并且测量的回波幅度比参考回波幅度大至少30%时，选择IMN的优化组件值和拓扑结构。通过观察塑料培养皿表面上的有形凹痕和在对靶细胞施加声脉冲后的单细胞响应来测试具有和不具有IMN的超声换能器的性能。
An approach for the design of an impedance matching network (IMN) for high frequency ultrasonic transducers with large apertures based on impedance analysis for cellular applications is presented in this paper. The main objectives were to maximize energy transmission from the excitation source to the ultrasonic transducers for cell manipulation and to achieve low input parameters for the safe operation of an ultrasonic transducer because the piezoelectric material in high frequency ultrasonic transducers is prone to breakage due to its being extremely thin. Two ultrasonic transducers, which were made of lithium niobate single crystal with the thickness of 15 μm, having apertures of 4.3 mm (fnumber = 1.23) and 2.6 mm (fnumber = 0.75) were tested. L-type IMN was selected for high sensitivity and compact design of the ultrasonic transducers. The target center frequency was chosen as the frequency where the electrical admittance (∣Y∣) and phase angle (θz) from impedance analysis was maximal and zero, respectively. The reference center frequency and reference echo magnitude were selected as the center frequency and echo magnitude, measured by pulse-echo testing, of the ultrasonic transducer without IMN. Initial component values and topology of IMN were determined using the Smith chart, and pulse-echo testing was analyzed to verify the performance of the ultrasonic transducers with and without IMN. After several iterations between changing component values and topology of IMN, and pulse-echo measurement of the ultrasonic transducer with IMN, optimized component values and topology of IMN were chosen when the measured center frequency from pulse-echo testing was comparable to the target frequency, and the measured echo magnitude was at least 30% larger than the reference echo magnitude. Performance of an ultrasonic transducer with and without IMN was tested by observing a tangible dent on the surface of a plastic petridish and single cell response after an acoustic pulse was applied on a target cell.