Local geometry defines the RF lineRT/duroid 5870 / 5880 datasheet explained. Engineering illustration, not a production photograph or test result.Local geometry defines the RF lineRT/duroid 5870 / 5880 datasheet explainedRT/duroid 5870 / 5880 datasheet explainedDielectric: use an appropriate model DkContinuous reference planeWidth WhAir / defined coverh is the distance to the reference plane, not total board thickness.