I have a question about EM simulation accuracy. I'm working with a very simple layout to learn the Momentum portion of ADS. The layout is just a ground plane with a transmission line on top. With default settings of 20 cells/wavelength and transmission line mesh unchecked my S11 or S22 show a high inductive component of the impedance. All other calculators show just pure resistive impedance. If I increase the c/w to a high number or enable transmission line mesh with a number close to 10, the reactive portion of the impedance goes almost to zero. Changing these settings, however, increases simulation time noticeably. I suspect that once I import a real board with many layers and complex geometries, the simulation will take days to complete. My question is if I can't get accurate results for a transmission line simulation with default settings, will all other simulation be inaccurate? Am I missing something? I believe I have all ports set correctly. My simulation frequency range is 1-2GHz.