What size should one choose at minimum/maximum for the pads and what role the pitch plays (besides impedance matching)? If I order a 100 micron tip diameter Ground Signal Ground GSG probe for contacting a coplanar waveguide where I do via lithography big contact pads and then taper the this large structure to the final wished geometry (signal ground line width some few microns), how big has the contact pad to be? Is 200-300 micron edge length enough assuming I can hit the pads with the probe tips by using a micromanipulator and optical microscope. So mainly for reasons of adjustment, or does a too low size of the pads effect negatively the electromagnetic wave propagation? In software like HFSS, CST, Sonnet the ports are mostly modeled as areas perpendicular to the signal and ground lines, does this really compare to picoprobe transition correctly?