100-MHz ultrasonic linear array transducers based on polyurea-film

Eight- and 32-element ultrasonic array transducers using polyurea films are fabricated and experimentally tested in this study. Aromatic polyurea thin films, prepared by vapor deposition polymerization, are suitable for use as an ultrasonic transducer. In this paper, we present two types of polyurea array transducer with 20 and 200 mu m pitches. The polyurea films were prepared through vapor deposition polymerization, and miniature electrode arrays were fabricated by a lithographic technique. Resonance frequencies of approximately 30, 65, and 100 MHz were observed in the electrical admittance. To examine the performances of the prototype array transducers, a pulse/echo test and phased array experiment were performed. From the experimental results, we found that the polyurea array transducers fabricated by the proposed method correctly operated as expected.