Problems with dense mesh in CST MWS

Good evening,
please help me
can we simulate an antenna in an environnement with CST MWS?
i did this, but i keep get a error message telling me tha the mesh is too dense, i tried to change it, so after that i got a error message telling me that the solver is exhausted and abort
how can i do this if there is an other methode?
with my respects,

CST have different solvers, using different methods.
For electrically large structures, they have an Integral Equation Solver:
High frequency 3D electromagnetic field simulation software - Frequency Domain Solver

Thank you so much for the answer, but i still have problems even when i used integral solver
an error message keep telling me "error in mesh generation. out of memory - could not generate mesh".
well my mesh properties as it is mentionned are :
steps per wavelength = 3
Min. number of steps = 2.0
i really want to understand how to generate the appropriate mesh.
thank you again

I am not a CST user.
If this "steps per wavelength" means cells/wavelength: I think that 10cells/wavelength is the absolute minimum in any EM tool. I usually use 20cells/wavelength. And yes, I understand that this will need even more memory.

Thank you so much, even i still didn't get a solution, but at least u answerd me, so thank u again