I have been designing 100 um wide coplanar waveguides in CST with 250 um substrate. When I try to define a waveguide port, I cannot use the macro since the line is too thin for the macro (~15 um less than the lowest acceptable for the macro). I have tried defining a port slightly larger than the lowest value possible from the macro. But I would like to know how reliable is this simulation. I also have lines closely spaced (400 um apart) and I need to simulate them all simultaneously. I cannot define a waveguide port here since they overlap. Using a discrete port results in strange results. I have also read that discrete ports are not meant to be used with coplanar waveguides. I would like to know how such a simulation will be possible. Is it even possible?