Simulation of scattering parameter of signal via with shielding vias

In the multi-layer circuit, the coupled microstrip-to-stripline vias interconnection structure lie between the two conducting plates. The adjacent two conducting plates form a radial waveguide. The current on the vertical via excites electromagnetic waves propagating inside the radial waveguide, so-called the radial waves. The radial waves interact with the TEM waves along the microwave transmission lines and exhibit more complicated mode. In this paper, the scattering parameter of signal via is simulated using the simulator Ansoft. The obtained results show that the scattering parameter can be changed by adding coax shielding via around signal via.