simulate_step_FEM#

simpleEMS.fem_backend.simulate_step_FEM(step_file: str, freqs: NDArray, *, unit: str = 'mm', dielectrics: dict | None = None, pec: list | None = None, lossy_conductor: dict | None = None, ports: dict | None = None, FEM_boundary: str = 'silver_muller', FEM_symmetry: tuple | None = None, FEM_fe_order: int = 1, FEM_air_pad_frac: float = 0.25, FEM_air_pad_mm: float | tuple | None = None, FEM_elems_per_wavelength: float = 16.0, FEM_mesh_freq: float | None = None, FEM_mesh_fine_scale: float = 1.0, FEM_min_layers: int = 3, FEM_num_solve_points: int = 10, FEM_max_solve_points: int | None = None, charac_imp: float = 50.0, output_path: str | Path = 'Sim_Path', run: bool = True, show_mesh: bool = True, mesh_style: str = 'wireframe', verbose: bool = True) → SimData#

Simulate a STEP geometry with the FEM backend and return the results.

A standalone entry point that needs no CSXCAD geometry: it meshes the STEP file, runs the frequency sweep, and returns the same results bundle the rest of the pipeline uses, so all SimTools post-processing applies.

Parameters:

  • step_file (str) – Path to the .step file to simulate.

  • freqs (NDArray) – Frequency points (Hz) to report results at.

  • unit (str) – Advisory only – the unit declared in the STEP file itself is what gets used. Default "mm".

  • dielectrics (dict, optional) – Dielectric solids, as {solid_name: (eps_r, tan_d)}.

  • pec (list, optional) – Names of solids to treat as perfect electric conductors.

  • lossy_conductor (dict, optional) – Lossy conductors, as {solid_name: sigma} with sigma in S/m.

  • ports (dict, optional) – Ports, as {solid_name: {"z0": ..., "direction": "x|y|z", "number": ..., "kind": "lumped|wave", "prop_dir": "x|y|z"}}. Only kind: "wave" reads prop_dir, the axis the line runs along; such a port’s solid must be the line’s cross-section, normal to it. If ports is omitted, solids whose names look like ports are used instead.

  • FEM_boundary (str) – Outer boundary condition: "silver_muller" (default), "pml" or "pec".

  • FEM_symmetry (tuple, optional) – Mirror-symmetry plane (axis, kind, at), so only half the structure is meshed. See FEMOptions. Default None.

  • FEM_fe_order (int) – Element order: 1 (default) or 2.

  • FEM_air_pad_frac (float) – Air padding around the structure, as a fraction of the longest wavelength. Default 0.25. Ignored when FEM_air_pad_mm is set.

  • FEM_air_pad_mm (float or tuple, optional) – Air padding around the structure in millimetres, used in place of FEM_air_pad_frac. Either one value for all six faces, three values [x, y, z], or three [low, high] pairs. Default None.

  • FEM_elems_per_wavelength (float) – Target number of mesh elements per wavelength. Default 16.0.

  • FEM_mesh_freq (float, optional) – Frequency the mesh is sized at, in Hz – both the element size and the air padding come off its wavelength. Default None, which sizes the mesh at the top of freqs. Name the frequency the structure was designed at to stop a wide sweep refining the mesh.

  • FEM_mesh_fine_scale (float) – Multiplier on the element size near conductors. Default 1.0.

  • FEM_min_layers (int) – Number of element layers through the dielectric thickness. Default 3.

  • FEM_num_solve_points (int) – Number of frequencies the sweep solves at (must be >= 4). Default 10.

  • FEM_max_solve_points (int, optional) – Ceiling on the solve count when the curve breaks passivity. Default None, which allows twice FEM_num_solve_points.

  • charac_imp (float) – Port reference impedance in ohms, used for any port that does not set its own. Default 50.0.

  • output_path (str | Path) – Working directory for the mesh, problem, and result files. Default "Sim_Path".

  • run (bool) – Whether to solve. If False, the geometry is only meshed and the results are read back from an earlier run in output_path. Default True.

  • show_mesh (bool) – Whether to show the created mesh. Default is True.

  • mesh_style (str) – mesh style to be used for visualisation. default is “wireframe”. other options are: “surface” | “wireframe” | “points”,

  • verbose (bool) – Print progress. Default True.

Returns:

Named tuple of freqs, s11, s21 (None for a single-port problem), z11, vswr, input_power, port_voltage, port_current, and ref_impedance. See SimData.

Return type:

SimData

Raises:

RuntimeError – If no ports are found or specified, or if run is False and output_path holds no results from an earlier run.

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