Study of self-focusing in underwater waveguide by time reversal method

Acoustic wave time reversal self-focusing in underwater waveguide is studied. The acoustic wave time reversal is theoretically and experimentally investigated in a half-infinite fluid medium and a shallow fluid layer placed on a hard half-infinite solid medium, respectively. The ray approach is adopted to study the acoustic field in theory, and the ultrasonic experiment has been carried out in laboratory to model the underwater waveguide. It is showed by theoretical and experimental studies that the focusing gain can be improved to more than 12 dB.