Design and fabrication of an annular array high intensity focused ultrasound transducer with an optimal electrode pattern

In this study, an annular high intensity focused ultrasound (HIFU) array transducer was developed to suppress the level of sidelobes below a given requirement with a minimum number of channels. The electrode patterns analyzed for the transducer were equal electrode area pattern and variable electrode width pattern. In finite element analysis of the transducer performance, the variable electrode width pattern transducer was proven to be able to suppress the level of sidelobes below −12 dB with 9 channels, while the equal electrode area pattern transducer required at least 10 channels to suppress the level of sidelobes by the same amount. Hence, the variable electrode width pattern was preferred for the annular array HIFU transducer. The validity of the comparison was verified by fabricating and characterizing prototypes of the transducer of each electrode pattern. The variable electrode width pattern annular array HIFU transducer is expected to be an effective tool for various therapeutic ultrasound applications.