In this work, we show electromagnetic simulations of surface roughness in multiple conventional antennas applicable for 6G networks potentially operating in the W-band (75–110 GHz). Operations at such high frequencies require  fine accuracy of surface processing that becomes to the order of the wavelength. We show simulations of the surface roughness of four devices, such as a horn antenna, a patch antenna, a rectangular waveguide, and a microstrip  transmission line. Finally, we simulated S-parameters and conducted statistical analysis to define the requirements of surface processing.