TRANSITION PROPERTIES OF A VERTICAL CONDUCTOR CONNECTING 2 MICROSTRIPLINES AT DIFFERENT PLANES

Transition properties of a vertical conductor connecting two semi-infi nite microstrip lines at different planes are analyzed by using dynami c solution techniques, This fundamental geometry is encountered in man y microwave interconnect and packaging applications, and in particular when three-dimensional multilayer metallization techniques are employ ed. In order to compute the reflection and transmission properties of this three-dimensional discontinuity, a method of moments technique is employed. To this end, the Green's function of the multilayer shielde d microstrip geometry is used. The surface current density distributio ns on the two semi-infinite microstrip lines are described in terms of the incident, reflected, and transmitted guided fundamental mode wave distributions plus a summation of current pulses in the region of dis continuity. The current on the vertical cylindrical connection line is also described in terms of a superposition of triangular shaped pulse s. Application of the boundary conditions on the three conductors lead s to a simultaneous linear system of equations by using a method of mo ments technique. Reflection and transmission coefficients are computed for several connection lines, and numerical results are presented. It is shown that a rather small connection conductor height can induce l arge reflection phenomena for an incident wave.