Two methods for calculating the amplitude of the acoustic sink, by introducing the concept of the sink in time reversal method, are proposed. The first method is to derive the amplitude of the phase conjugation array in the focusing location of the acoustic sources directly, which is employed as the amplitude of the acoustic sink. The second method is to calculate the amplitude of the acoustic sink by introducing the measurement spherical surface. The effect of the spherical radius on focusing properties is also discussed. The numerical results show that the diffraction limit can be broken through at a certain distance by introducing the acoustic sink for the two methods. The best reconstruction can be obtained by considering the spherical measurement surface, that can yield more accurate results which agree well with the theoretical solution of the point source. The radius of the spherical measurement surface must be less than the wavelength according to the properties of the evanescent waves.

The phase conjugation method has been used for the identification and reconstruction of the complex sources. A plate subject to point force is involved to verify the effectiveness of the method. Numerical results show that the best identification results could be achieved by the array made of dipole transceivers based on pressure gradient measurement in the near field. The phase conjugation method for identification and localization of the radiated field has advantages of no ill-posedness difficulty and using a small number of measurements and is natural to use patch method. These features may make the phase conjugation method a powerful noise diagnostic tool.