A 256-channel Ultrasound Phased Array System : Driving System and Transducer Design

• Main Authors: Jyun An Lin, 林俊安
• Other Authors: H. L. Liu
• Format: Others
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/76682659940939086650

碩士 === 長庚大學 === 電機工程學研究所 === 97 === Focused ultrasound technology has confirmed that has the therapeutic effect for biological tissues, and temporarily opens the blood-brain barrier and does the functions of the brain to carry out local drug delivery in recent years. At present, for thermal ablation purpose, the frequency range of the driving system typically larger than 0.5 MHz for better tissue absorption and rapid temperature increase. However, the above frequency range encounters severe bone absorption and focal beam distortion to make the transcranial ultrasound therapy becomes difficult. The purpose of this study is to design a low-frequency 256-channel ultrasound phased array driving system for electronic phase shift to achieve a focus and real-time power monitoring function. The prototype system contains 256-channel driving module, multiple-channel power sensoring module, and one 256-channel hemispherical ultrasound phased array. Output power for each channel feed back to the control kernel by using a dual directional coupler circuit to let the control panel real-time monitor the power output. System performance testing includes output power testing, feedback power testing, acoustic pressure testing and ultrasound pressure measurements. Our results showed that the system can successfully generate ultrasonic focus, and the focal position can be steered by precisely controlling the relative phases of elements.