Impedance calculator issue

Question

I am using the impedance calculator for a 14 layer PCB, and although I have only roughly set up the stack the data is not too far out. However I am getting a stupid width for a 50R impedance of 22mm. the 14 layers give a total thickness of 3mm with Fr4 @0.2032mm and copper of 0.03048, dielectric constant of 4.5. What am I missing? 
 I tried an old design just 4 layers and the values were equally ridiculously out.

Thanks Jessica.

excellon1 · Accepted Answer

Jessica in order for the PCB editor to calculate impedance the physical reference layer needs to be set as a Plane. 
 For example Layer 1 is top and set as a conductor. L2_GND should be set as a plane layer. Doing so will allow you to calculate the desired impedance on layer 1. 
 It can be confusing because one might think it would not be possible to route traces on a plane layer but this is not the case. On your stackup in the picture just set L2_GND & L5_PWR to a type of "Plane" and the impedance solver should work as desired.

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Impedance calculator issue

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