High frequency ultrasonics using PZT sol gel composites

Piezoelectric arrays suitable for high frequency ultrasound have been fabricated using PZT sol gel composite coatings in the thickness range of 5-100 mu m on aluminum and platinized alumina substrates. The coatings have been quantitatively characterized using impedance measurements to 100 MHz. The analysis provides a direct measure of the piezoelectric coupling coefficient of k(t) < 0.34. 16 element linear array structures suitable for ultrasound biomicroscopy at 30-40 MHz with elements having dimensions similar to 40 mu m thick, 20-25 mu m wide and 15 mu m spacing have been patterned using excimer based laser micromachining. The dielectric and pulse echo responses have been measured.