Dear @gotou,
There is a fundamental misunderstanding here. The EM LF Electro Ohmic Quasi-Static solver, is frequency-independent. The complex part of the fundamental electro quasi-stati equation \nabla\cdot\tilde\epsilon\nabla\phi = 0 (see Sim4Life manual, "2.6.1.4 Choosing the Appropriate Low Frequency Solver") is not solved AT ALL, since it is assumed that you have chosen this solver after having evaluated that the condition $\sigma>>\omega \epsilon_r \epsilon_0$ is valid for all the tissues and materials in your simulation at the frequency of interest. How to quantify this condition is also explained in the manual. The frequency has not impact on your simulation at all when you choose this solver.
If you are unsure whether the condition $$\sigma>>\omega \epsilon_r \epsilon_0$$ applies, then you should consider to use the QS solver (not Ohmic-Current dominated) solver that solves the full complex equation. This solver uses both the conductivity and the permittivity and is frequency dependent. Please read the manual before running any further simulation if you have not clear which limitations apply to each solver: this is very important to proceed further.
However, as @bryn also pointed out, the problem is then to decide which dielectric properties should be used. I agree with his observation.
If your application uses sufficiently small frequencies, i.e. up to several tents of kHz, we suggest that you use the Ohmic current dominated solver in combination with the LF-IT'IS tissue properties.
If you want further help, you should mention the type of application (e.g. neurostimulation) and the frequencies of interest. We could suggest you further documentation and scientific literature.
