Efficient computation of thin-layer structures with the unconditionally stable ADI-FDTD method

Efficient computation is a key consideration in computational electromagnetics, especially for complex VLSI structures that contain thin dielectric layers or electrically small objects. Due to the CFL stability condition, it is very inefficient to apply the conventional FDTD method to thin-layer structures because fine mesh (and therefore small time step) is required. In this paper, the unconditionally stable ADI-FDTD method is employed to circumvent the difficulty. With applications in computing effective dielectric constant (/spl epsiv//sub eff/) and characteristic impedance (Z/sub 0/) of cylindrical microstrip lines, it is shown that the computation time with the ADI-FDTD method is much shorter than that of the conventional FDTD method without sacrificing modeling accuracy.