What is the best solver for optical nanoantennas?

For optical nanoantennas, the choice between time-domain and frequency-domain solvers depends on the specific application and the features being analyzed:

Frequency-Domain Solver:Best for narrowband structures with a small range of operating frequencies. Provides high resolution for resonant modes and scattering parameters (S11). Useful when analyzing materials with dispersive properties as it directly computes steady-state solutions. Ideal for structures with fine resonances or high-Q factors.

Time-Domain Solver:Suited for wideband analysis since it calculates responses in the time domain and then performs Fourier transforms. Useful for broadband antennas or when transient effects are significant. More computationally efficient for structures requiring a wide frequency sweep.

Why are your results different?

Mesh Discretization: Mesh density and quality can affect results differently in both solvers.

Material Dispersion Models: Ensure material properties (e.g., refractive index) are properly modeled in both solvers, especially for dispersive materials like metals.

Boundary Conditions and Ports: Check boundary conditions and port settings for consistency.

Solver Settings: Time-domain solvers rely on transient behavior, and convergence criteria or simulation time can influence results.

Recommendation:

If your structure is narrowband and the frequency solver results appear correct, stick with the frequency-domain solver.
For validation, you may run a convergence study in both solvers to ensure mesh and simulation parameters do not bias results.

Mahdiah Stiri

hello Mehran, thank you very much. my results are completely different the mesh with frequency solver settings is tetrahedral and the mesh in time domain solver settings is hexahedral. I examine the s_{1,1} parameter and radiation pattern which are completely different depending on the solver I have chosen. in frequency solver, i has got the sinusoidal curve for s_{1,1} but in time solver, i has got the parabolic curve and in the time domain solver i have got more lobes in comparison with frequency solver

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