The Target Scattering Characteristic Of Objects Under The Interface

This dissertation is at the background of the detection of buried mines and has researched the scattering of object below the interface between two kinds of medium. Taking T-matrix method, we analyze and calculate the scattering field above the interface in the up medium which is produced by the wave source located in the up medium acting on the object under the interface. The purpose of the paper is to prepare for the theory of the bistatic sonar system detecting the buried mine.Firstly, we've used T-matrix method calculating rigid and static ball's scattering field on the condition of free field and compared with the result which is calculated by normal function's method. Secondly, after validating the correctness of the results through comparing, we use the T-matrix method to calculate the medium-ball's scattering field and analyze the characteristic of it. The efficiency of the method when it is used for calculating the medium-sphere's scattering field has been tested.Towards to the interface existing case, we use wave function and boundary conditions to solve the coefficient's relationship between interface's surface field, medium-ball's sphere field and incidence field. The transfer-matrix of fields' coefficient has been derived, named as T-matrix. The distribution of the scattering field in the water has been simulated and calculated when the wave source locate in it and acting on the rigid ball locate in the sand layer below. Finally, with the water tank experiment we test the efficiency when the method is used for calculating the buried object's scattering field and analyzed the error and its origin between the theory and the experiment. According to the error, we have a summarization.