The different between transient/frequency solver in CST ?

FDTD vs FEM?

Frequency domain FDFD and FDTD it is only solver mode..

i agree 2rd floor

MWS is particularly using the FIT method (Finite Integration Technique),
the brother of the FDTD method. Those two techniques are similar but
not identical.

Hi

Time Domain Solver - good for big structures (less memory hungry), arbitrary excitation signals (like square waves or pulses), broadband problems

frequency Domain Solver - good for small problems (like RF-CMOS structures), use of Floquet Modes applied to non-normal incidence (on Frequency Selective Surfaces), low frequency applications (like RFID for the kHz-range) and very high Q-filters (if simulated in time domain require a huge time to get it done).

Both solvers are original from the FIT - Finite Integration Technique - which works on the Integral Formulation of the Maxwell Equations.

peace

Hi everyone,

Thanks first.
I have a question regarding the frequency solver.
Usually I use the transient solver to simulate the antennas and the result is sufficient for me.
However, now I have a microstrip patch antenna, which is highly resonant structure. The transient sovlver gave me some ambiguous results. For example, when I simulate from 1 to 3 GHz, the S11 at 1.57GHz is -20dB. But when I solve from 1 to 20 Ghz, the S11 at 1.575Ghz becomes -7dB. Someone suggests that I should use the frequncy domain solver.
However, I encounter this problem everytime and the solver automatically stopped.
"The port number 1 is located inside the computation domain, but not backed with a solid block of PEC material".
Anyonw knows what this means? I don't understand at all.

laura1282

Hi laura1282,

For the frequency domain solver :go to Objects in CST menu, pick the port excitation face, extrude in the negative direction (-1 for example) then assign the PEC to the solid created.

I hope this will help.