A parameter-scanning method for acoustic matching layers based on KLM equivalent circuit

When fabricating acoustic matching layers for ultrasonic transducers, usually it is very hard to find materials with characteristic impedances as predicted by classical formulas. Based on the KLM equivalent circuit for ultrasonic transducers, the parameters (characteristic impedance and thickness) of acoustic matching layer(s) were scanned. The resulted matching effectiveness charts (characteristic impedance vs. output power and thickness vs. output power) can be used to seek optimized matching layer parameters. When piezoelectric material was PZT5 and working media was water, calculations showed that compared with parameters determined by classical formulas, this method could effectively elongate the bandwidth by 2~4 times.