CST Microwave Studio. Collimator modelling.

Colleagues,
I met with the problem while trying to calculate amplitude distribution on planar surface at a certain distance (200-400 wavelength) from the collimator aperture. The problem is that the calculation process reach?s RAM limit (16 GB) and terminates with error when I use time domain solver. Obviously, it happens because of large dimensions of the collimator, approximately 100x100 wavelength. On the other hand, when I use integral solver, calculation completes succesfully, but for integral solver it is impossible to use ?Draw 3d fields on 2d plane? tool.
Is there any possibility to solve my problem with microwave studio functionality? May be some tricks for optimising RAM usage?
Regards.

hi,
1) reduce total design mesh density. you can reduce in steps until simulator successfully complete the simulation.
2) reduce mesh density of particular section of the design. if you feel particular piece of the conductor not significantly affecting the design parameters, you can reduce the mesh density in that area.
3) if you have many conductor pieces join together to form an antenna, merge the conductor pieces into one. it will reduce mesh density.