A numerical methodology is presented for fast broad-band extraction of the
electromagnetic properties of passive waveguiding structures. The methodolo
gy combines the standard finite-difference time-domain (FDTD) method with a
nonsymmetric Lanczos eigenvalue algorithm to extract a reduced-order model
of the electromagnetic response over the frequency range of interest. The
implementation of the algorithm is such that each iteration is computationa
lly equivalent to the update of the electromagnetic fields in the FDTD algo
rithm, However, no time stepping is required.