Comparison of long-wavelength T-matrix multiple-scattering theory and size-dependent Maxwell-Garnett formula

Wave attenuation in a dielectric-in-dielectric composite is calculated usin g the long-wavelength T-matrix multiple-scattering theory and the size-depe ndent Maxwell-Garnett formula. Results obtained are first compared, and the n followed by their comparisons with the experimental results and other the oretical results. An interesting observation made is that the size-dependen t Maxwell-Garnett formula predicts monotonically increasing wave attenuatio n with increasing concentration of inclusions, whereas the computed results from the multiple-scattering theory theory and other formulas, together wi th the experimental results, indicate maximum wave attenuation at a certain concentration of inclusions. It is shown that the size-dependent Maxwell-G arnett formula gives good prediction of wave attenuation only up to inclusi on concentration of about 2%, and the T-matrix multiple-scattering theory i n the long-wavelength approximation gives good prediction of wave attenuati on even beyond the inclusion concentration of 2%. (C) 1999 John Wiley & Son s, Inc.