I'm simulating an exported from Altium designer 16.1 Rigid Flex PCB board, which contains suppose to be 100 ohm diff pairs . The Hyperlink calculates its Zdiff as 82 ohm for some reason .
1. The designed PCB with correct PCB stack-up and Diff pare parameters where set in the Altium .
2. Exported as HYP file from Altium and opened in Hyperlynx V9.4 . All passed well, with correct traces drawing and layers stack-up . The ref / signal planes were selected .
3. The selected diff traces where extracted from BoardSim to LineSim , in order to review a transmission lines topology and impedance.
Somehow, the calculated by Hyperlynx differential embedded microistrip impedance is 82.1 ohm, while it suppose to be 100 ohm according to its layers stack-up and Er.
Attachment 1.jpg - screen of LineSim with all the related geometric parameters of transmission line with a wrong calculated Zdiff.
Attachment 2.jpg - the correct calculated Zdiff by two known impedance calculators using the same trace and stack-up parameters.
Where is my mistake ?