A deep-submergence, very low-frequency, broadband, Multiport Transducer

The back radiation from a transducer is typically out-of-phase with the front radiation requiring isolation between the two. This is particularly difficult to achieve if the transducer is broadband and operated under significant ambient pressure. The Multiport Transducer offers a solution to this problem by using free-flooded resonance chambers on both the inside and outside radiating surfaces of a transducer. With these chambers in place cancellation is avoided and the pressure adds between the resonant frequencies of the two chambers. Two Multiport Transducers with coaxial tubes driven by piezoelectric ring arrays will be presented. The transducers have fundamental resonant frequencies of 600 Hz and 200 Hz with bandwidths of nearly one-octave. Results from finite element and circuit analysis models are presented and compared with measured results.