Added PECMedium to IsotropicUniformMediumType, and added PEC2D

tests/sims/simulation_2_5_0rc1.json

@@ -302,6 +302,100 @@
                 }
             }
         },
+        {
+            "geometry": {
+                "type": "Box",
+                "center": [
+                    -1.0,
+                    0.0,
+                    0.0
+                ],
+                "size": [
+                    1.0,
+                    0.0,
+                    1.0
+                ]
+            },
+            "name": null,
+            "type": "Structure",
+            "medium": {
+                "name": null,
+                "frequency_range": null,
+                "allow_gain": false,
+                "nonlinear_spec": null,
+                "heat_spec": null,
+                "type": "Medium2D",
+                "ss": {
+                    "name": "PEC",
+                    "frequency_range": null,
+                    "allow_gain": false,
+                    "nonlinear_spec": null,
+                    "heat_spec": null,
+                    "type": "PECMedium"
+                },
+                "tt": {
+                    "name": "PEC",
+                    "frequency_range": null,
+                    "allow_gain": false,
+                    "nonlinear_spec": null,
+                    "heat_spec": null,
+                    "type": "PECMedium"
+                }
+            }
+        },
+        {
+            "geometry": {
+                "type": "Box",
+                "center": [
+                    -1.0,
+                    0.0,
+                    0.0
+                ],
+                "size": [
+                    1.0,
+                    1.0,
+                    1.0
+                ]
+            },
+            "name": null,
+            "type": "Structure",
+            "medium": {
+                "name": null,
+                "frequency_range": null,
+                "allow_gain": null,
+                "nonlinear_spec": null,
+                "heat_spec": null,
+                "type": "AnisotropicMedium",
+                "xx": {
+                    "name": "PEC",
+                    "frequency_range": null,
+                    "allow_gain": false,
+                    "nonlinear_spec": null,
+                    "heat_spec": null,
+                    "type": "PECMedium"
+                },
+                "yy": {
+                    "name": null,
+                    "frequency_range": null,
+                    "allow_gain": false,
+                    "nonlinear_spec": null,
+                    "heat_spec": null,
+                    "type": "Medium",
+                    "permittivity": 1.0,
+                    "conductivity": 0.0
+                },
+                "zz": {
+                    "name": null,
+                    "frequency_range": null,
+                    "allow_gain": false,
+                    "nonlinear_spec": null,
+                    "heat_spec": null,
+                    "type": "Medium",
+                    "permittivity": 1.0,
+                    "conductivity": 0.0
+                }
+            }
+        },
         {
             "geometry": {
                 "type": "GeometryGroup",

tests/utils.py

@@ -139,6 +139,14 @@
             geometry=td.Box(size=(1, 0, 1), center=(-1, 0, 0)),
             medium=td.Medium2D.from_medium(td.Medium(conductivity=0.45), thickness=0.01),
         ),
+        td.Structure(
+            geometry=td.Box(size=(1, 0, 1), center=(-1, 0, 0)),
+            medium=td.PEC2D,
+        ),
+        td.Structure(
+            geometry=td.Box(size=(1, 1, 1), center=(-1, 0, 0)),
+            medium=td.AnisotropicMedium(xx=td.PEC, yy=td.Medium(), zz=td.Medium()),
+        ),
         td.Structure(
             geometry=td.GeometryGroup(geometries=[td.Box(size=(1, 1, 1), center=(-1, 0, 0))]),
             medium=td.PEC,

tidy3d/__init__.py

@@ -11,7 +11,8 @@
 from .components.geometry.polyslab import PolySlab
 
 # medium
-from .components.medium import Medium, PoleResidue, AnisotropicMedium, PEC, PECMedium, Medium2D
+from .components.medium import Medium, PoleResidue, AnisotropicMedium, PEC, PECMedium
+from .components.medium import Medium2D, PEC2D
 from .components.medium import Sellmeier, Debye, Drude, Lorentz
 from .components.medium import CustomMedium, CustomPoleResidue
 from .components.medium import CustomSellmeier, FullyAnisotropicMedium
@@ -159,6 +160,7 @@ def set_logging_level(level: str) -> None:
     "PEC",
     "PECMedium",
     "Medium2D",
+    "PEC2D",
     "Sellmeier",
     "Debye",
     "Drude",

tidy3d/components/grid/mesher.py

@@ -16,7 +16,7 @@
 from ..base import Tidy3dBaseModel
 from ..types import Axis, ArrayFloat1D
 from ..structure import Structure, MeshOverrideStructure, StructureType
-from ..medium import PECMedium, Medium2D
+from ..medium import Medium2D
 from ...exceptions import SetupError, ValidationError
 from ...constants import C_0, fp_eps
 
@@ -373,7 +373,7 @@ def structure_steps(
         min_steps = []
         for structure in structures:
             if isinstance(structure, Structure):
-                if isinstance(structure.medium, (PECMedium, Medium2D)):
+                if structure.medium.is_pec or isinstance(structure.medium, Medium2D):
                     index = 1.0
                 else:
                     n, k = structure.medium.eps_complex_to_nk(

tidy3d/components/medium.py

@@ -452,6 +452,11 @@ def sigma_model(self, freq: float) -> complex:
         sigma = (eps_inf - eps_complex) * 1j * omega * EPSILON_0
         return sigma
 
+    @cached_property
+    def is_pec(self):
+        """Whether the medium is a PEC."""
+        return False
+
 
 class AbstractCustomMedium(AbstractMedium, ABC):
     """A spatially varying medium."""
@@ -621,6 +626,11 @@ def n_cfl(self):
         """
         return 1.0
 
+    @cached_property
+    def is_pec(self):
+        """Whether the medium is a PEC."""
+        return True
+
 
 # PEC builtin instance
 PEC = PECMedium(name="PEC")
@@ -2667,7 +2677,7 @@ def eps_dataarray_freq(
         return (eps, eps, eps)
 
 
-IsotropicUniformMediumType = Union[Medium, PoleResidue, Sellmeier, Lorentz, Debye, Drude]
+IsotropicUniformMediumType = Union[Medium, PoleResidue, Sellmeier, Lorentz, Debye, Drude, PECMedium]
 IsotropicCustomMediumType = Union[
     CustomPoleResidue,
     CustomSellmeier,
@@ -2808,6 +2818,11 @@ def elements(self) -> Dict[str, IsotropicUniformMediumType]:
         """The diagonal elements of the medium as a dictionary."""
         return dict(xx=self.xx, yy=self.yy, zz=self.zz)
 
+    @cached_property
+    def is_pec(self):
+        """Whether the medium is a PEC."""
+        return any(isinstance(med, PECMedium) for med in self.components.values())
+
 
 class FullyAnisotropicMedium(AbstractMedium):
     """Fully anisotropic medium including all 9 components of the permittivity and conductivity
@@ -3856,6 +3871,13 @@ def n_cfl(self):
         """
         return 1.0
 
+    @cached_property
+    def is_pec(self):
+        """Whether the medium is a PEC."""
+        return any(isinstance(med, PECMedium) for med in self.elements.values())
+
+
+PEC2D = Medium2D(ss=PEC, tt=PEC)
 
 # types of mediums that can be used in Simulation and Structures
 

tidy3d/components/simulation.py

@@ -22,7 +22,7 @@
 from .types import Ax, Shapely, FreqBound, Axis, annotate_type, Symmetry, TYPE_TAG_STR, InterpMethod
 from .grid.grid import Coords1D, Grid, Coords
 from .grid.grid_spec import GridSpec, UniformGrid, AutoGrid
-from .medium import Medium, MediumType, AbstractMedium, PECMedium
+from .medium import Medium, MediumType, AbstractMedium
 from .medium import AbstractCustomMedium, Medium2D, MediumType3D
 from .medium import AnisotropicMedium, FullyAnisotropicMedium, AbstractPerturbationMedium
 from .boundary import BoundarySpec, BlochBoundary, PECBoundary, PMCBoundary, Periodic
@@ -809,7 +809,7 @@ def _warn_grid_size_too_small(cls, val, values):
                 for medium_index, medium in enumerate(mediums):
 
                     # min wavelength in PEC is meaningless and we'll get divide by inf errors
-                    if isinstance(medium, PECMedium):
+                    if medium.is_pec:
                         continue
                     # min wavelength in Medium2D is meaningless
                     if isinstance(medium, Medium2D):
@@ -1589,7 +1589,7 @@ def _get_structure_plot_params(self, mat_index: int, medium: Medium) -> PlotPara
         if mat_index == 0 or medium == self.medium:
             # background medium
             plot_params = plot_params.copy(update={"facecolor": "white", "edgecolor": "white"})
-        elif isinstance(medium, PECMedium):
+        elif medium.is_pec:
             # perfect electrical conductor
             plot_params = plot_params.copy(
                 update={"facecolor": "gold", "edgecolor": "k", "linewidth": 1}
@@ -1722,7 +1722,7 @@ def eps_bounds(self, freq: float = None) -> Tuple[float, float]:
         """Compute range of (real) permittivity present in the simulation at frequency "freq"."""
 
         medium_list = [self.medium] + list(self.mediums)
-        medium_list = [medium for medium in medium_list if not isinstance(medium, PECMedium)]
+        medium_list = [medium for medium in medium_list if not medium.is_pec]
         # regular medium
         eps_list = [
             medium.eps_model(freq).real
@@ -1829,7 +1829,7 @@ def _get_structure_eps_plot_params(
         if alpha is not None:
             plot_params = plot_params.copy(update={"alpha": alpha})
 
-        if isinstance(medium, PECMedium):
+        if medium.is_pec:
             # perfect electrical conductor
             plot_params = plot_params.copy(
                 update={"facecolor": "gold", "edgecolor": "k", "linewidth": 1}