An electrical impedance matching method of dual-frequency transducers for ultrasound internal imaging

• Published in: Measurement : journal of the International Measurement Confederation Vol. 221; p. 113413
• Main Authors: Li, Jiaqi, Huang, Wenchang, Shao, Weiwei, Li, Xiangxin, Shen, Zhitian, Xu, Jie, Shen, Jun, Cui, Yaoyao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.11.2023
• Subjects: Dual-frequency impedance matching method; Echo Performance Improvement; Impedance matching network; Large frequency interval transducer; Impedance matching network; Echo Performance Improvement; Large frequency interval transducer; Dual-frequency impedance matching method
• ISSN: 0263-2241
• DOI: 10.1016/j.measurement.2023.113413

[Display omitted] •A method for electrical impedance matching of a single transducer with two large frequency intervals is proposed.•Design and optimize the matching network of the large frequency interval dual-frequency interventional ultrasound transducer to simultaneously enhance the echo signals of two frequencies.•Compared with before and after matching, the echo amplitudes of low frequency and high frequency increased by 1.86 times and 2.26 times respectively, and system noise was also decreased by 29.6%. A micro single transducer with two resonant frequencies can solve the inherent contradiction between detection depth and resolution by simultaneously emitting two frequency bands of ultrasonic waves. But the difference of impedance values in the two resonant frequency bands seriously affects dual-frequency echo signal efficiency. In order to improve the quality of transducer sensitivity, a dual-frequency electrical impedance matching method is proposed in the study. By selecting a specific matching structure to match one frequency without messing up the impedance of another frequency, the two frequencies can be designed independently to achieve preliminary impedance matching. The matching networks for single frequency are combined to form a complete dual-frequency matching circuit, and adjust the initial matching value to obtain a suitable matching state. The performances of the matching network have been tested and verified by experiments. After matching, the low-frequency and high-frequency sensitivities of the transducer increased 1.86 times and 2.26 times, respectively. In addition, system noise was also reduced by 29.6% after adding the matching network. The results demonstrate that this dual-frequency matching network can simultaneously increase the amplitude of high-frequency and low-frequency echoes to obtain better quality images.