Singularity correction at PEC and lossy metal edges

Author: weiliangjin2021

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Simulation.precision` option allows to select `"double"` precision for very high-accuracy results. Note that this is very rarely needed, and doubles the simulation computational weight and correpsondingly FlexCredit cost.
 - Added material type `PMCMedium` for perfect magnetic conductor.
 - `ModeSimulation.plot()` method that plots the mode simulation plane by default, or the containing FDTD simulation if any of ``x``, ``y``, or ``z`` is passed. 
+- Enable singularity correction at PEC and lossy metal edges.
 
 ### Changed
 - Switched to an analytical gradient calculation for spatially-varying pole-residue models (`CustomPoleResidue`).

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 and 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),
+            lossy_metal=td.SurfaceImpedance(edge_singularity_correction=False),
+        ),
+    )
+
+    sim = sim.updated_copy(
+        subpixel=td.SubpixelSpec(
+            pec=td.PECConformal(edge_singularity_correction=True),
+            lossy_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

@@ -120,6 +120,14 @@ class PECConformal(AbstractSubpixelAveragingMethod):
         ge=0,
     )
 
+    edge_singularity_correction: bool = pd.Field(
+        False,
+        title="Apply Singularity Model At Metal Edges",
+        description="Apply field correction model at metallic edges where field singularity occurs. "
+        "The edges should be straight, and 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