MULTIPLE MULTIPOLE METHOD FOR SIMULATING EM PROBLEMS INVOLVING BIOLOGICAL BODIES

The three-dimensional implementation of the multiple multipole (MMP) m ethod, based on the generalized multipole technique (GMT), is presente d. Its performance in simulating electromagnetic problems involving bi ological bodies is analyzed. In particular, the step-by-step simulatio n technique and the built-in procedures to validate the solution on nu merical basis are discussed and demonstrated in two examples. A compar ison is made with other numerical techniques often applied in this fie ld. The advantages of the MMP method are shown to be in its validation capability, in its efficiency for smoothly shaped bodies and in the a chievable accuracy, in particular near boundaries. The method is espec ially suited to handle high-gradient fields in the vicinity of biologi cal bodies. On the other hand, finite difference (FD) techniques are s uperior for scatterers with complicated angular shapes or inhomogeneou s bodies, for which MMP shows rather strong practical limitations. How ever, in most cases the inhomogeneities of biological bodies modify th e field distribution only locally beyond the uncertainties of models. In these cases, inhomogeneities can be stimulated efficiently and with high accuracy by MMP applying the block iterative technique. Other me thods are not general enough to compete with FD or MMP in solving EM p roblems involving biological tissues.