Zipparo, “Ultrasonic transducers and arrays
- M.K.K. Shung
- IEEE Engineering in Medicine and Biology,
The quarter-wavelength (hi4) acoustic matching layer is a vital component in medical ultrasonic transducers, which can bridge the large acoustic impedance mismatch between the piezoelectric material and the human body. .At high frequencies (>5OMHz), the hi4 matching layers become extremely thin and the characterization of its properties becomes very challenging. We report a novel method to measure the phase velocity and attenuation of ultra-thin layers using the h/4 matching principle. The method has been successfully used to measure a 14.6pm Epo-Tek 301 epoxy film on glass substrate and a 9.5pm sol-gel silicon oxide colloidalipolymer composite film on Si substrate.