Thermal analysis and SNR comparison of CMUT and PZT transducers using coded excitation

Coded excitation (CE) is a powerful technique to enhance ultrasound image quality and penetration by improving signal-to-noise ratio (SNR). While its benefits are well established, CE can raise concerns over transducer overheating, often exceeding safe temperature limits—an aspect rarely addressed in literature. In this study, researchers compared the thermal performance of capacitive micromachined ultrasonic transducers (CMUTs) with traditional PZT probes under CE conditions. Using IEC-standard thermal testing and phantom experiments, the CMUT demonstrated superior thermal efficiency, remaining well within safety limits while achieving up to 14 dB SNR gain and 30 mm increased penetration depth. By contrast, the PZT probe reached the temperature threshold in just 3 minutes, with no gain in SNR or depth. Both probes stayed within FDA acoustic output limits, confirming temperature—not intensity—is the primary limiting factor for CE use. 

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