  We propose a technique of compensating the spurious reflections implied by
the multiple-scattering (MS) method, commonly used for analyzing finite
photonic crystal (PC) systems, to obtain exact values of characteristic
parameters, such as reflection and transmission coefficients, of PC functional
elements. Rather than a modification of the MS computational algorithm, our
approach involves postprocessing of results obtained by the MS method. We
derive analytical formulas for the fields excited in a finite system, taking
explicitly into account the spurious reflections occurring at the artificial
system boundaries. The intrinsic parameters of the investigated functional
element are found by fitting the results of MS simulations to those obtained
from the formulas derived. Devices linked with one and two semi-infinite
waveguides are analyzed explicitly; possible extensions of the formalism to
more complex circuits are discussed as well. The accuracy of the proposed
method is tested in a number of systems; the results of our calculations prove
to be in good agreement with those obtained independently by other authors.
