Design and Fabrication of a High-Frequency Microconvex Array Transducer for Small Animals Imaging

High-frequency convex array transducer, featuring both high spatial resolution and wide field of view, has been successfully developed for ophthalmic imaging. To further expand its application range to small animals’ imaging, this work develops a high-frequency microconvex array transducer possessing smaller aperture size and wider scanning angle. This transducer featured 128 array elements arranged in a curvilinear 2–2 piezoelectric composite configuration, yielding a maximum view angle of 97.8°. The array was composed of two front matching layers, a nonconductive backing layer, and a customized flexible circuit that electrically connected array elements to coaxial cables. The center frequency and the −6-dB fractional bandwidth were about 18.14 MHz and 69.15%, respectively. The image of a tungsten wire phantom resulted in approximately 62.9-
$ {\mu } \text{m}$
axial resolution and 121.3-
$ {\mu }\text{m}$
lateral resolution. The image of the whole kidney of a rat as well as its internal arteries was acquired
in vivo
, demonstrating the imaging capability of the proposed high-frequency microconvex array transducers for small animals’ imaging applications.