Patent ID: 8817575

Claim:
A transducer assembly for parametric sonar comprising: a transmitting layer capable of generating two primary high frequency signals, said two primary high frequency signals having a non-zero difference frequency, said two primary high frequency signals being capable of interfering to produce a low frequency acoustic beam at the difference frequency, said transmit layer having a thickness of about one-half wavelength of an operating range of said two primary high frequency signals; at least one filtering layer located adjacent to said transmitting layer capable of reducing back acoustic radiation created by said transmitting layer; and a receiving layer located adjacent to said at least one filtering layer such that said at least one filtering layer is interposed between said transmitting layer and said receiving layer, said receiving layer having a thickness suited to resonance at the difference frequency; wherein said at least one filtering layer comprises: a first back radiation reduction layer made from an unvoided polymeric backfill material; and a second back radiation reduction layer having metallic blocks positioned in the same unvoided polymeric backfill material as the transmitting and receiving layers, said second back radiation reduction layer providing mass loading.