Yes, dielectric constant (Dk), dissipation factor (Df), are interpolated from material tables that vary with frequency. Loss, too, is frequency dependent.
Yes. At high frequencies, current increasingly flows through the perimeter of a signal conductor. This is referred to as the “skin effect.” The depth at which the current flows is called “skin depth,” and is typically denoted by d (um). As frequency increases, skin depth gets progressively smaller. As skin depth approaches the surface roughness of the copper, they must be considered together when simulating signal attenuation. There are several ways to measure copper roughness, but the most commonly-available parameter is Rz (um), so Z-planner utilizes this parameter rather than other alternative roughness measures to simulate copper roughness loss as a function of frequency.
