Improve support for wave port boundaries in a SolidModel (#111)

* Add capability to render 1D line segments in SolidModel

* WIP tests adding wave ports to SolidModel

* WIP tests adding wave ports to SolidModel

* Fix formatting

* Remove comments

* Add boolean to control wave vs lumped ports

* Improve waveport specification

* WIP single indexable waveport layer

* Add wave ports by automatically detecting path intersections with simulation area

* Add test and improve wave port intersection handling

* Update CHANGELOG and comments

* Update CHANGELOG

* Remove unused line segment methods and improve test case

* Fix formatting

* Split SolidModel wave port test into two tests for single and flip chip

* Address PR feedback and add warning when wave port path/boundary are not perpendicular

Author: simlapointe

CHANGELOG.md

@@ -7,11 +7,17 @@ The format of this changelog is based on
 ## Upcoming
 
   - Added `xor2d` for polygon XOR
+  - Improved support for wave port boundaries in a `SolidModel`
+
+      + `SolidModelTargets` now take `wave_port_layers`, a list of layer symbols used to define wave port boundary conditions
+      + Added support for `LineSegment` in SolidModel
+      + Added `add_wave_ports!` to automatically place wave port boundaries where specified paths/routes intersect the simulation area
+      + Added option to use wave ports instead of lumped ports in the single transmon example
 
 ## 1.6.0 (2025-10-16)
 
   - Improved metadata handling for `LayoutTarget` and `SolidModelTarget`
-    
+
       + SolidModelTargets will now ignore `NORENDER_META` (the `:norender` layer)
       + SolidModelTargets now take `ignored_layers`, a list of layer symbols which are not rendered
       + LayoutTargets now allow overriding the mapping of `GDSMeta` by setting `target.map_meta_dict[my_gdsmeta] = my_override`, allowing changes to different `GDSMeta` or `nothing` rather than always mapping a `GDSMeta` to itself
@@ -29,7 +35,7 @@ The format of this changelog is based on
 ## 1.5.0 (2025-10-10)
 
   - Added `auto_speed`, `endpoints_curvature`, and `auto_curvature` keyword options to `bspline!` and `BSplineRouting`
-    
+
       + `auto_speed` sets the speed at endpoints to avoid sharp bends (minimizing the integrated square of the curvature derivative with respect to arclength)
       + `endpoints_curvature` sets boundary conditions on the curvature (by inserting extra waypoints)
       + `auto_curvature` B-spline sets curvature at endpoints to match previous segment (or to zero if there is no previous segment)

examples/SingleTransmon/SingleTransmon.jl

@@ -5,7 +5,7 @@ module SingleTransmon
 using FileIO, CSV, DataFrames, JSON, JSONSchema
 using DeviceLayout, DeviceLayout.SchematicDrivenLayout, DeviceLayout.PreferredUnits
 import .SchematicDrivenLayout.ExamplePDK
-import .SchematicDrivenLayout.ExamplePDK: LayerVocabulary, L1_TARGET, add_bridges!
+import .SchematicDrivenLayout.ExamplePDK: LayerVocabulary, L1_TARGET, add_bridges!, add_wave_ports!
 using .ExamplePDK.Transmons, .ExamplePDK.ReadoutResonators
 import .ExamplePDK.SimpleJunctions: ExampleSimpleJunction
 import DeviceLayout: uconvert
@@ -24,6 +24,7 @@ using PRIMA
         n_meander_turns=5,
         hanger_length=500μm,
         bend_radius=50μm,
+        wave_ports::Bool=false,
         save_mesh::Bool=false,
         save_gds::Bool=false)
 
@@ -41,6 +42,7 @@ function single_transmon(;
     n_meander_turns=5,
     hanger_length=500μm,
     bend_radius=50μm,
+    wave_ports::Bool=false,
     save_mesh::Bool=false,
     save_gds::Bool=false,
     mesh_order=2
@@ -90,7 +92,7 @@ function single_transmon(;
         bridge=BRIDGE_STYLE
     )
     ## Readout path
-    readout_length = 2700μm
+    readout_length = wave_ports ? 4mm : 2700μm
     p_readout = Path(
         Point(0μm, 0μm);
         α0=π / 2,
@@ -101,15 +103,17 @@ function single_transmon(;
     straight!(p_readout, readout_length / 2, PATH_STYLE)
 
     # Readout lumped ports - squares on CPW trace, one at each end
-    csport = CoordinateSystem(uniquename("port"), nm)
-    render!(
-        csport,
-        only_simulated(centered(Rectangle(cpw_width, cpw_width))),
-        LayerVocabulary.PORT
-    )
-    # Attach with port center `cpw_width` from the end (instead of `cpw_width/2`) to avoid corner effects
-    attach!(p_readout, sref(csport), cpw_width, i=1) # @ start
-    attach!(p_readout, sref(csport), readout_length / 2 - cpw_width, i=2) # @ end
+    if !wave_ports
+        csport = CoordinateSystem(uniquename("port"), nm)
+        render!(
+            csport,
+            only_simulated(centered(Rectangle(cpw_width, cpw_width))),
+            LayerVocabulary.PORT
+        )
+        # Attach with port center `cpw_width` from the end (instead of `cpw_width/2`) to avoid corner effects
+        attach!(p_readout, sref(csport), cpw_width, i=1) # @ start
+        attach!(p_readout, sref(csport), readout_length / 2 - cpw_width, i=2) # @ end
+    end
 
     #### Build schematic graph
     g = SchematicGraph("single-transmon")
@@ -130,7 +134,7 @@ function single_transmon(;
 
     #### Prepare solid model
     # Specify the extent of the simulation domain.
-    substrate_x = 4mm
+    substrate_x = 4mm # wave port domain boundary needs to touch the readout line
     substrate_y = 3.7mm
 
     center_xyz = DeviceLayout.center(floorplan)
@@ -144,10 +148,17 @@ function single_transmon(;
     # Define rectangle that gets extruded to generate substrate volume
     render!(floorplan.coordinate_system, chip, LayerVocabulary.CHIP_AREA)
 
+    # Add wave ports
+    wave_ports && add_wave_ports!(floorplan, [p_readout_node], sim_area, 0.6mm, LayerVocabulary.WAVE_PORT)
+
     check!(floorplan)
 
     # Need to pass generated physical group names so they can be retained
-    tech = ExamplePDK.singlechip_solidmodel_target("port_1", "port_2", "lumped_element")
+    if wave_ports
+        tech = ExamplePDK.singlechip_solidmodel_target("wave_port_1", "wave_port_2", "lumped_element")
+    else
+        tech = ExamplePDK.singlechip_solidmodel_target("port_1", "port_2", "lumped_element")
+    end
     sm = SolidModel("test", overwrite=true)
 
     # Adjust mesh_scale to increase the resolution of the mesh, < 1 will result in greater
@@ -178,7 +189,7 @@ function single_transmon(;
 end
 
 """
-    configfile(sm::SolidModel; palace_build=nothing, solver_order=2, amr=0)
+    configfile(sm::SolidModel; palace_build=nothing, solver_order=2, amr=0, wave_ports=false)
 
 Given a `SolidModel`, assemble a dictionary defining a configuration file for use within
 Palace.
@@ -190,7 +201,7 @@ Palace.
     high-order spaces.
   - `amr = 0`: Maximum number of adaptive mesh refinement (AMR) iterations.
 """
-function configfile(sm::SolidModel; palace_build=nothing, solver_order=2, amr=0)
+function configfile(sm::SolidModel; palace_build=nothing, solver_order=2, amr=0, wave_ports=false)
     attributes = SolidModels.attributes(sm)
 
     config = Dict(
@@ -234,19 +245,37 @@ function configfile(sm::SolidModel; palace_build=nothing, solver_order=2, amr=0)
                 "Attributes" => [attributes["exterior_boundary"]],
                 "Order" => 1
             ),
+            (wave_ports ?
+                (
+                    "WavePort" => [
+                        Dict(
+                            "Index" => 1,
+                            "Attributes" => [attributes["wave_port_1"]]
+                        ),
+                        Dict(
+                            "Index" => 2,
+                            "Attributes" => [attributes["wave_port_2"]]
+                        ),],
+                )
+                : ()
+            )...,
             "LumpedPort" => [
-                Dict(
-                    "Index" => 1,
-                    "Attributes" => [attributes["port_1"]],
-                    "R" => 50,
-                    "Direction" => "+X"
-                ),
-                Dict(
-                    "Index" => 2,
-                    "Attributes" => [attributes["port_2"]],
-                    "R" => 50,
-                    "Direction" => "+X"
-                ),
+                (wave_ports ? () :
+                    (
+                        Dict(
+                            "Index" => 1,
+                            "Attributes" => [attributes["port_1"]],
+                            "R" => 50,
+                            "Direction" => "+X"
+                        ),
+                        Dict(
+                            "Index" => 2,
+                            "Attributes" => [attributes["port_2"]],
+                            "R" => 50,
+                            "Direction" => "+X"
+                        ),
+                    )
+                )...,
                 Dict(
                     "Index" => 3,
                     "Attributes" => [attributes["lumped_element"]],
@@ -258,7 +287,7 @@ function configfile(sm::SolidModel; palace_build=nothing, solver_order=2, amr=0)
         ),
         "Solver" => Dict(
             "Order" => solver_order,
-            "Eigenmode" => Dict("N" => 2, "Tol" => 1.0e-6, "Target" => 1, "Save" => 2),
+            "Eigenmode" => Dict("N" => 2, "Tol" => 1.0e-6, "Target" => 2.5, "Save" => 2),
             "Linear" => Dict("Type" => "Default", "Tol" => 1.0e-7, "MaxIts" => 500)
         )
     )

src/DeviceLayout.jl

@@ -365,6 +365,7 @@ include("polygons.jl")
 import .Polygons:
     Polygon,
     Ellipse,
+    LineSegment,
     Circle,
     ClippedPolygon,
     RelativeRounded,
@@ -390,6 +391,7 @@ import .Polygons:
 export Polygons,
     Polygon,
     Ellipse,
+    LineSegment,
     Circle,
     ClippedPolygon,
     RelativeRounded,

src/polygons.jl

@@ -63,7 +63,7 @@ import IntervalTrees: IntervalTree, IntervalValue
 import IntervalSets.(..)
 import IntervalSets.endpoints
 
-export Polygon, ClippedPolygon, Ellipse, Circle
+export Polygon, ClippedPolygon, Ellipse, Circle, LineSegment
 export circle,
     circle_polygon,
     clip,
@@ -1517,12 +1517,16 @@ end
 
 ### cutting algorithm
 
-abstract type D1{T} end
+abstract type D1{T} <: GeometryEntity{T} end
 Δy(d1::D1) = d1.p1.y - d1.p0.y
 Δx(d1::D1) = d1.p1.x - d1.p0.x
 
 ab(p0, p1) = Point(gety(p1) - gety(p0), getx(p0) - getx(p1))
 
+to_polygons(::D1{T}) where {T} = Polygon{T}[]
+
+transform(d1::T, f::Transformation) where {T <: D1} = T(f(d1.p0), f(d1.p1))
+
 """
     LineSegment{T} <: D1{T}
 

src/schematics/ExamplePDK/ExamplePDK.jl

@@ -67,6 +67,7 @@ const LAYER_RECORD = (;
     simulated_area = GDSMeta(200, 0),
     port           = GDSMeta(210, 0),
     lumped_element = GDSMeta(211, 0),
+    wave_port      = GDSMeta(212, 0),
     mesh_control   = GDSMeta(220, 0),
     integration    = GDSMeta(230, 0)
 )
@@ -104,10 +105,14 @@ const EXAMPLE_FLIPCHIP_TECHNOLOGY = ProcessTechnology(
     (;  # Use unrealistic thicknesses for the sake of clearer visualizations
         chip_thicknesses=[100μm, 100μm], # [Bottom chip, top chip] (for calculating z height by level)
         flipchip_gaps=[80μm], # Space between chip surfaces (for calculating z height by level)
-        height=(; simulated_area=-1mm), # z height at the bottom of simulation volume
+        height=(; # z height at the bottom
+            simulated_area=-1mm,
+            wave_port=[-160μm, -160μm]
+        ),
         thickness=(; # Extrusion distances for various layers
             simulated_area=2mm,
             chip_area=[100μm, 100μm], # For levelwise layers, specify thickness for each level
+            wave_port=[400μm, 400μm],
             bump=80μm
         )
     )
@@ -121,8 +126,15 @@ single chip assembly.
 const EXAMPLE_SINGLECHIP_TECHNOLOGY = ProcessTechnology(
     LAYER_RECORD,
     (;
-        height=(; simulated_area=-1mm), # z height at the bottom of simulation volume
-        thickness=(; simulated_area=2mm, chip_area=525μm) # Extrusion distances for various layers
+        height=(; # z height at the bottom
+            simulated_area=-1mm,
+            wave_port=-200μm
+        ),
+        thickness=(; # Extrusion distances for various layers
+            simulated_area=2mm,
+            chip_area=525μm,
+            wave_port=400μm
+        )
     )
 )
 
@@ -153,7 +165,8 @@ const SINGLECHIP_SOLIDMODEL_TARGET = SolidModelTarget(
     simulation=true, # Optional simulation-only geometry entities will be rendered
     bounding_layers=[:simulated_area], # SIMULATED_AREA defines the simulation bounds
     substrate_layers=[:chip_area], # CHIP_AREA will be extruded downward
-    indexed_layers=[:port, :lumped_element, :integration], # Automatically index these layers
+    indexed_layers=[:port, :lumped_element, :integration, :wave_port], # Automatically index these layers
+    wave_port_layers=[:wave_port], # WAVE_PORT are 1D line segments in x-y to be extruded in z
     postrender_ops=[ # Manual definition of operations to run after 2D rendering
         (   # Get metal ground plane by subtracting negative from writeable area
             "metal", # Output group name
@@ -242,9 +255,11 @@ const FLIPCHIP_SOLIDMODEL_TARGET = SolidModelTarget(
         :metal_positive,
         :chip_area, # and for chip and bridge extrusion in opposite directions by layer
         :bridge_base,
-        :bridge
+        :bridge,
+        :wave_port
     ],
-    indexed_layers=[:port, :lumped_element, :integration],
+    indexed_layers=[:port, :lumped_element, :integration, :wave_port],
+    wave_port_layers=[:wave_port],
     postrender_ops=[
         (   # Get metal ground plane by subtracting negative from writeable area
             "metal_L1",