Ultra wideband multiple resonant transducer

Tonpilz piston transducers are generally operated in the vicinity of their fundamental resonance while operation above resonance is usually required for wider band performance. However, this wide band performance is often limited by nulls in the response due to cancellation between the modes of vibration and the inability of the drive system to perform at these null frequencies. The Multiple Resonant (MR) transducer concept avoids these problems and excites a large number of extensional resonant modes of a distributed transducer system in a way, which allows addition between these modes. Our approach uses a distributed transmission line transducer with the transduction elements specifically situated to excite both odd and even numbered modes (1, 2, 3, etc.), accomplishing in-phase addition between modes. Wide bandwidth is obtained by excitation of all the modes up to the frequency at which the active transduction element is one wavelength long. Feedback control is used to smooth the response and provide velocity control under interactive array steered conditions.