Broadband, acoustically transparent, nonresonant PVDF hydrophone

A hydrophone assembly comprising:

• voided piezoelectric polymer sensing element means, having a characteristic acoustic impedance (.rho.c) selected to match that of sea water and a sensitivity based upon a preselected element means thickness, for producing electrical signals proportional to acoustic pressure waves impinging thereon:
• a first electrical transmission means, the proximal end thereof being conductively attached to said sensing element means, for receiving and transmitting said electrical signals;
• preamplifier means, attached to the distal end of said electrical transmission means, for receiving and amplifying said electrical signals from said electrical transmission means;
• a second electrical transmission means, the proximal end thereof being conductively attached to said preamplifier means, for receiving said amplified signals from said preamplifier means and transmitting said amplifier signals to the distal end thereof;
• and
• and elastomer window material, having an acoustic impedance (.rho.c) matching that of sea water and also matching said impedance of said sensing element means, said window material being potted under vacuum over said sensing element means, said first and second electrical transmission means, and said preamplifier means, for forming a waterproof covering for said hydrophone assembly which is at least acoustically transparent over said sensing element;
• whereby said .rho.c voided sensing element means, in combination with said .rho.c elastomer window, form an acoustically transparent, non-resonant hydrophone assembly having a flat frequency response at frequencies <1 MHz.