More than 100 billion mesh cells are not supported

My design have extremely thin parts. I have heard that long thing solids in CST means the program can have difficulty analyzing such structure. The error message 'More than 100 billion mesh cells are not supported.' always come up when i want to simulate. Is there a way around this at all?

Can you change the mesh size? A larger mesh would have fewer cells. They should only need to be 1/10th of a wavelength, or not a whole lot smaller than that.