If you are trying to tune the dielectric constant for a substrate and are getting strange or unexpected results, please make sure that you do not have something like "?4.6" for the Er in the substrate properties; this is incorrect usage.
The correct way to do this is to set a variable equal to a tuneable variable in the equations, then set that variable into the substrate properties, as in the attached screenshot.
The correct way to do this is to set a variable equal to a tuneable variable in the equations, then set that variable into the substrate properties, as in the attached screenshot.
