A pvdf membrane hydrophone for operation in the range 0.5 Mhz to 15 Mhz

A new form of hydrophone for measuring the spatial and temporal distributions of pressure within the fields from medical ultrasonic equipment is described. The device comprises an acoustically transparent plastic membrane with a small, central region activated to provide a freely-suspended piezoelectric element. This form of detector offers several advantages over conventional hydrophone probes employing ceramic elements, in particular a flat frequency response. The performance characteristics of a prototype membrane hydrophone and some possible developments and applications are described.