Accurate prediction of microstrip impedance and attenuation at millimeter-wave frequencies

The European research project LIPS (Low Cost Interconnect, Packaging and Sub-system Integration Technologies for Millimeter-wave Applications) aims to enhance today's low cost packaging technologies for use at millimeter-wave frequencies. A 60 GHz WL4N transceiver; representing a typical high volume application, serves as a demonstrator for the investigated laminate technology. Different EM simulation tools were used to make accurate preliminary performance estimations and early suggestions for process enhancement. Special attention was given to design rules for 50 Ω impedance and microstrip transmission losses at 60 GHz target frequency. The scope of this paper is the discussion of physical and analytical observations that allow to overcome typical limitations of the used simulation tools such as surface roughness, equivalent line width extension or mixed dielectric build ups. It also shows the approach of concurrently use several tools with different methods to increase the credibility of simulation results.