Singularity correction at metallic edges

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added heat sources with custom spatial dependence. It is now possible to add a `SpatialDataArray` as the `rate` in a `HeatSource`.
 - Added Transient Heat simulations. It is now possible to run transient Heat simulations. This can be done by specifying `analysis_spec` of `HeatChargeSimulation` object as `UnsteadyHeatAnalysis`. 
 - A `num_grid_cells` field to `WavePort`, which ensures that there are 5 grid cells across the port. Grid refinement can be disabled by passing `None` to `num_grid_cells`.
+- Enable singularity correction at PEC edges.
 
 ### Fixed
 - Fixed bug in broadband adjoint source creation when forward simulation had a pulse amplitude greater than 1 or a nonzero pulse phase.

tests/test_components/test_simulation.py

@@ -2385,6 +2385,27 @@ def test_conformal_dt():
     assert sim_heuristic.dt == dt
 
 
+def test_edge_correction():
+    """make sure edge correction can be enabled for PEC, but not lossy meal."""
+    sim = td.Simulation(
+        size=(2.0, 2.0, 2.0),
+        run_time=1e-12,
+        structures=[],
+        grid_spec=td.GridSpec.uniform(dl=0.1),
+        subpixel=td.SubpixelSpec(pec=td.PECConformal(edge_singularity_correction=False)),
+    )
+
+    sim = sim.updated_copy(
+        subpixel=td.SubpixelSpec(pec=td.PECConformal(edge_singularity_correction=True))
+    )
+
+    # but cannot be True for lossy metal
+    with pytest.raises(pydantic.ValidationError):
+        sim = sim.updated_copy(
+            subpixel=td.SubpixelSpec(metal=td.SurfaceImpedance(edge_singularity_correction=True))
+        )
+
+
 def test_sim_volumetric_structures(tmp_path):
     """Test volumetric equivalent of 2D materials."""
     sigma = 0.45

tidy3d/components/subpixel_spec.py

@@ -6,7 +6,7 @@
 import pydantic.v1 as pd
 
 from .base import Tidy3dBaseModel, cached_property
-from .types import TYPE_TAG_STR
+from .types import TYPE_TAG_STR, Literal
 
 # Default Courant number reduction rate in PEC conformal's scheme
 DEFAULT_COURANT_REDUCTION_PEC_CONFORMAL = 0.3
@@ -120,6 +120,14 @@ class PECConformal(AbstractSubpixelAveragingMethod):
         ge=0,
     )
 
+    edge_singularity_correction: bool = pd.Field(
+        True,
+        title="Apply Singularity Model At Metal Edges",
+        description="Apply field correction model at metallic edges where field singularity occurs. "
+        "The correction is applied to straight edges aligned with the primal grids, and the wedge angle is either "
+        "0 or 90 degree.",
+    )
+
     @cached_property
     def courant_ratio(self) -> float:
         """The scaling ratio applied to Courant number so that the courant number
@@ -146,6 +154,14 @@ class SurfaceImpedance(PECConformal):
         ge=0,
     )
 
+    edge_singularity_correction: Literal[False] = pd.Field(
+        False,
+        title="Apply Singularity Model At Metal Edges",
+        description="Apply field correction model at metallic edges where field singularity occurs. "
+        "The correction is applied to straight edges aligned with the primal grids, and the wedge angle is either "
+        "0 or 90 degree.",
+    )
+
 
 LossyMetalSubpixelType = Union[Staircasing, VolumetricAveraging, SurfaceImpedance]