Numerical Study of a Microstrip Line with a Two-Layer Dielectric Substrate of Finite Width

An open microstrip line with a two-layer substrate of SiO₂ and Al₂O₃, employed in millimeter-wave range mikroelectronic devices, has been numerically studied. The dependences of the characteristic electrodynamical properties of this line upon its geometrical parameters were calculated. For computations, the method of singular integral equations in the quasistatic approximation was applied. Double complexity was introduced: with respect to time and to coordinates. This method allows taking into account even very large losses in the material of the microstrip line substrate. The computation algorithm permitted us to take into account the finite strip conductor thickness and substrate width.