FDFD Settings #

This section describes the settings for FDFD solvers.

Select the FDFD button in the Home tab and click any empty space in the Composite viewer to create an FDFD solver. Then modify the settings of the FDFD solver in the automatically pop-up Edit properties interface to complete the addition of the FDFD solver.

FDFD Solver Settings #

General Settings #

The General tab is used to set the simulation space (including simulation and geometric dimensions) for the solver.

Simulation Dimension #

The Dimension and polarization tab is used to set the simulation dimensions for the FDFD solver.

Name	Description
2D Polarization	TE: TE-polarization, for example: including three components $E_z$, $E_x$, $H_y$; TM: TM-polarization, for example: including three components $E_y$, $H_z$, $H_x$.
2.5D	2.5D simulation.

Geometry #

The Geometry tab is used to set the size parameters of the FDFD solver.

Name	Description
Z/X/Y pos	Set the center of the solver.
Z/X/Y span	Set the scope of the solver.

2.5D Settings #

The 2.5D settings tab is only enabled when the simulation dimension is set to 2.5D.

For detailed parameter settings, see 2.5D settings.

FDFD #

The FDFD tab is used to set the wavelength and frequency of the simulation and select the material sampling type.

The Wavelength/Frequency tab is used to set the wavelength and frequency of the simulation.

Material Sampling #

In the FDFD solver, different frequency sampling methods can be selected for material data corresponding to different material types.

• Sampled material sampling type

For sampled materials, the material data is discrete data at different frequencies, and there are two sampling methods:

Name	Description
Linear interpolation	When applying the Linear interpolation to acquire material data at different frequencies, the resulting material data may have discontinuities in frequency.
Fit model	Use a polynomial material model to fit and obtain Sampled material data at different frequencies.

• Analytic material sampling type

For analytic materials, material data is calculated directly from physical formulas, such as Debye, Drude, Lorentz models, etc. There are two sampling methods for material data at different frequencies:

Name	Description
Analytic model	Use the dispersion model of the Analytical material to calculate data.
Fit model	Use a polynomial material model to fit and obtain Analytic material data at different frequencies.

When the Fit model is selected as the Material sampling type, the menu bar of Fit bandwidth is editable.

Background Material #

The Background Material tab provides the Background Material drop-down menu for users to select background materials.

Name	Description
Background material	The background material library, including materials from the Global library. You can also use the Add/Edit in the Project library to create project-specific materials as background materials

After selecting a background material, its relevant information (Name, Type, Last modified, etc.) is displayed simultaneously.

Mesh #

The Mesh tab provides the mesh settings for solvers.

For detailed parameter settings, see Mesh.

Boundary Conditions #

The Boundary conditions tab provides the boundary condition settings for the FDFD solver. For the frequency-domain solver, boundary conditions define the interaction between the simulation region and the external space at the min/max boundaries. The supported boundary types include PML / Periodic / Bloch / PEC / PMC / Symmetric / Anti-symmetric.

• PML: absorbs outgoing electromagnetic waves from the simulation region and reduces reflections that contaminate the frequency-domain solution;
• Periodic: models repeated translational symmetry and requires matching min/max boundaries in the same direction;
• Bloch: handles phase-corrected periodic problems such as oblique incidence on a periodic structure and requires matching min/max boundaries in the same direction;
• PEC / PMC: use PEC or PMC boundary conditions to impose specific field constraints, enforcing zero tangential electric or magnetic fields at the boundary;
• Symmetric/Anti-Symmetric Boundary: uses image symmetry of the structure and excitation to reduce the simulation region and improve efficiency.

For more detailed definitions, equations, and parameter settings, see Boundary Conditions.

Advanced Settings #

The Advanced tab provides the advanced settings for solvers.

Name	Description
Force symmetric x/y/z mesh	Forced mesh symmetry in the x/y/z direction. Only the positive-axis half of the simulation region needs to be considered; the mesh of the negative-axis half replicates that of the positive-axis half. This option allows generation of simulation meshes based on user-defined wavelength ranges.