Reflectivity measurements using a large aperture PVDF hydrophone

A measurement technique is presented in which the frequency dependence of the reflection coefficient of solid samples can be assessed with the need for calibration against a perfect reflector. The technique gives results that are independent of both diffraction and focusing effects. It is based on the use of a diffraction-insensitive (DI) hydrophone, and both the incident and the reflected waves can be detected by the same device in the same experiment. The transmissivity function of the DI hydrophone was measured over the 1-8 MHz frequency range. The results were used to correct for the reflectivity values obtained for several solid rods of steel, aluminum, perspex, and neoprene in water