This page is the reference lane (its URL slug): the configuration to start from and the calculations whose limits are narrower than it.
Start with the uniform grid
Use the uniform Cartesian Yee solver for ordinary RF examples and public reports. The commonly documented setup includes:
- PEC, CPML, or UPML boundaries within their stated limits;
- point/current sources and the port type appropriate to the structure;
- probes, flux monitors, Harminv resonance extraction, selected S-parameter calculations, and the documented far-field workflows; and
- convergence checks and an analytic or independent solver comparison suited to the reported observable.
The support matrix gives the general limits. For port calculations, also read the S-parameter guidance.
Calculations with narrower limits
| Configuration | Current use and restriction |
|---|---|
| rectangular waveguide S-matrix | Use compute_waveguide_s_matrix(...) for the documented rectangular-guide modes, frequency bands, normalization, reference planes, and port placement. Magnitude evidence is broader than phase and arbitrary-junction evidence. |
| microstrip-line S-matrix | Use compute_msl_s_matrix(...) for the documented quasi-TEM configurations. Exclude the whole frequency slice S[:, :, k] wherever reliable[p, k] is false (S is solved jointly across drives, #507); a true entry is not an accuracy guarantee. |
| lumped or wire-port S-parameters | Use run(compute_s_params=True) or the documented differentiable S11 path. These discrete lumped/wire feed models are not modal transmission-line ports. |
| coaxial transmission-line reflection | Use compute_coaxial_line_reflection(...) only with float32 precision, a nonperiodic 3D second-order uniform Yee grid, CPML on all six boundary faces with positive thickness on both z faces, cpml_axes="z", and exactly one face="top" coaxial port. It builds its own line, source, probes, and termination, is not a general multi-port coaxial-network solver, and has no shared automatic passivity guard. See Sources and Ports. |
| nonuniform graded-z mesh | Check the limit for each source, port, and observable. Regression or finite-gradient coverage alone does not establish RF accuracy. |
| differentiable design | Treat the optimization quantity as a proxy objective. Validate the final design independently with the applicable RF observable. |
S-parameter API selection
run(compute_s_params=True)computes lumped/wire-port S-parameters.compute_msl_s_matrix(...)computes the microstrip-line result.compute_waveguide_s_matrix(...)computes the rectangular-waveguide result.compute_coaxial_line_reflection(...)computes the one-port line-reflection result for the float32, nonperiodic 3D second-order uniform Yee and all-face CPML setup described above. Separately registered geometry, circuit elements, monitors, and coaxial termination helpers are rejected.- Field sources, TFSF, probes, DFT planes, and flux monitors do not define a port impedance or S-matrix reference plane.
Do not substitute one calculator for another port family. A completed run or an absent warning does not establish convergence, passivity, reference-plane correctness, or agreement with an independent RF reference. Examples and regression tests do not expand those validated limits either: a committed test locks the behaviour it was written against, at the mesh, band and configuration it was written for.