FDTD simulation of lossless metals

Hi everyone,

I want to simulate waveguides made up of lossless metals. For such structures, metal's refractive index is purely imaginary. What implication does it have for courant factor? We know that S <= min(n)/sqrt(#dimensions). Since minimum refractive index in my simulation is now zero, does this mean that FDTD is incapable of handling this object?

Thanks.

All FDTD software that I know supports lossless metal (perfect conductor). No problem.

What you model is the medium (air). The waveguide forms the boundary.

No. FDTD can handle most materials. But your 'lossless metal' confuses me a bit.
Can you translate it into 'normal' FDTD terms. Do you mean negative permittivity?
At a fixed frequency? Then the normal method would be to set up a dispersive model
for these parameters and then use ADE or (PL)RC to model such materials