I'm trying to extract s-parameters from a PCB. I am evaluating Sonnet right now. What an awesome tool. It's very user friendly. It's super accurate, as far as I can measure, with a thick PCB. Say 1mm.
However, when I try to model a thin PCB, say 0.1mm, the results are way off to the point of being unusable. Does any other EM tool / 2.5D solver handle thin dielectrics?
Btw, I work at UHF, at few hundred MHz.
(Just to be clear, a tool based on circuit theory works well too, but has limitations. Circuit theory tools use manual schematic entry and the PCB has to be modelled as sections of transmission lines or microstrips. What I'm trying to achieve is to get something less labour intensive and more accurate than a circuit theory tool.)