Comparative Assessment of Plane Wave Imaging with 256-element CMUT and Single Crystal Probes

Non-standard scan modes, based on the transmission of plane and diverging waves, are the key to enable high frame rate and volumetric imaging modalities and are promising in the implementation of novel system architectures for ultra-integrated (high channel count) scanners. So far, capacitive micromachined ultrasonic transducer (CMUT) arrays have been benchmarked against standard piezoelectric transducers only in standard modalities. In this work, a 256-element CMUT probe and a state-of-the art single crystal composite piezoelectric probe, sharing the same array geometry and bandwidth, are compared in plane wave (PW) imaging mode. The CMUT probe provided, on average, improved signal power (+9 dB) and contrast (+3 dB) for all PW aperture angles. Also, compared to the piezoelectric probe, the CMUT one offered comparable axial resolution, but slightly worse (10%) lateral resolution.