The eigenmode problem for multilayered structures with coplanar or non-coplanar strips is analysed using the space domain Green's dyadic of these structures as the kernel of an integral equation. The integral equation is solved using the method of moments combined with point-matching. The calculation of the Green's dyadic starts in the spectral domain. First, an efficient solution technique is presented to determine the spectral Green's dyadic. Special attention is then devoted to its behaviour for large values of the Fourier variable and to the contribution of this asymptotic part to the space domain Green's dyadic. The behaviour of the fields in the vicinity of the excitation is determined explicitly. The method is illustrated by two typical examples.