ELECTROMAGNETIC SCATTERING FROM 2-DIMENSIONAL ELECTRICALLY LARGE PERFECTLY CONDUCTING OBJECTS WITH SMALL CAVITIES AND HUMPS BY USE OF ADAPTIVE MULTISCALE MOMENT METHODS (AMMM)

Three kinds of AMMM are presented for an evaluation of electromagnetic scattering from electrically large perfectly conducting objects with small cavities and humps. These techniques employ the conventional mom ent method and a special matrix transformation, which is derived from the multiscale technique, to compute the scattering from two-dimension al complex objects on a non-uniform grid. The matrix equations of the three kinds of AMMM can be obtained directly from the impedance matrix of the conventional moment method by a matrix multiplication. The mai n advantage of these techniques is that it can reduce automatically th e size of the linear equations constructed by the conventional moment method so as to improve the efficiency of the MoM. Several numerical r esults are presented, which demonstrates that AMMM is a useful tool to analyze the scattering from large complex objects.