in SIWave you can simulate the PKG of a chip, you can use also HFSS and Q3D from Ansoft. if you go for any of these directions, you should use the Ansoft Links tool to import your bondwires/solderballs/layout/etc. For higher freq you should use HFSS, if your structure is electrically short (lambda/10 rule) you can use Q3D, both tools are 3D Field Solvers. SIWave is a 2.5D solver, it aproximates the 3D sections, and but it solves very good the 2D parts. hope this helps