An Improved Phased Array Ultrasonic Probe Using 0.91Pb(Zn_1/3Nb_2/3)O₃–0.09PbTiO₃ Single Crystal

A 96-channel phased array probe for echocardiography using a single-plate, 0.91Pb(Zn_1/3Nb_2/3)O₃–0.09PbTiO₃ (PZNT 91/9) single-crystal transducer with dimensions of 14×20 mm has been fabricated to realize greater sensitivity and broader bandwidth properties. The center frequency of the probe, 3.5 MHz, was selected to cover the bandwidths of two conventional lead zirconate titanate (PZT) ceramic probes with center frequencies of 2.5 and 3.75 MHz. A solder paste was used to connect a flexible printed circuit to the PZNT 91/9 transducer. The echo amplitude of the PZNT 91/9 probe is about 6 dB higher than that of the two PZT probes, and the fractional bandwidths are 30 and 25 percentage points wider, respectively. The B-mode image quality of the PZNT 91/9 probe is comparable to that of the two PZT probes, and the Doppler sensitivity of the PZNT 91/9 probe is almost equal to that of the 2.5 MHz PZT probe, which means that the PZNT 91/9 probe matches both the penetration of the 2.5 MHz PZT probe and the resolution of 3.75 MHz PZT probe.