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Running Palace Simulations: Microstrip

Palace is an open-source 3D electromagnetic simulator supporting eigenmode, driven (S-parameter), and electrostatic simulations. This notebook demonstrates using the gsim.palace API to run a driven simulation on a microstrip transmission line with via ports.

Requirements:

  • IHP PDK: uv pip install ihp-gdsfactory
  • GDSFactory Simulation SDK: uv pip install gsim
  • GDSFactory+ account for cloud simulation

Load a pcell from IHP PDK

import gdsfactory as gf

from ihp import LAYER, PDK, cells

PDK.activate()

c = gf.Component()
r1 = c << cells.straight_metal(length=1000, width=14)

r = c.get_region(layer=LAYER.TopMetal2drawing)
r_sized = r.sized(+20000)
c.add_polygon(r_sized, layer=LAYER.Metal1drawing)


c.add_ports(r1.ports)

cc = c.copy()
cc.draw_ports()
cc

png

Configure and run simulation with DrivenSim

from gsim.palace import DrivenSim

# Create simulation object
sim = DrivenSim()

# Set output directory
sim.set_output_dir("./palace-sim-microstrip")

# Set the component geometry
sim.set_geometry(c)

# Configure layer stack from active PDK
sim.set_stack(substrate_thickness=2.0)

# Surround the stack with air to keep the absorbing side boundaries
# away from the trace and ground plane.
sim.set_airbox(margin_x=50.0, margin_y=50.0, z_above=300.0)

# Configure via ports (Metal1 ground plane to TopMetal2 signal)
for port in c.ports:
    sim.add_port(port.name, from_layer="metal1", to_layer="topmetal2", geometry="via")

# Configure driven simulation (frequency sweep for S-parameters)
sim.set_driven(fmin=1e9, fmax=100e9, num_points=300)

# Validate configuration
print(sim.validate_config())

pyvirtualdisplay not available; continuing without Xvfb


Validation: PASSED

# Generate mesh (presets: "coarse", "default", "fine")
sim.mesh(preset="default")

Mesh Summary
========================================
Dimensions: 1140.0 x 154.0 x 317.9 µm
Nodes:      9,221
Elements:   70,749
Tetrahedra: 49,229
Edge length: 0.42 - 285.00 µm
Quality:    0.502 (min: 0.002)
SICN:       0.536 (all valid)
Worst element distortion, κ: 315.774 (tet centers; 1 is ideal)
Estimated Field DOFs: 319,962 (order 2; before Palace preprocessing)
Mesh hash:  sha256:0269758daf3d4169  (gmsh 4.15.2, gsim 0.7.0)
Mesher:     2D algorithm 5, 3D algorithm 1, threads 1 (1D/2D/3D limits 1/1/1)
----------------------------------------
Volumes (3):
  - sio2 [1]
  - sin [2]
  - air [3]
Surfaces (11):
  - metal1_xy [4]
  - metal1_z [5]
  - topmetal2_xy [6]
  - topmetal2_z [7]
  - P1 [8]
  - P2 [9]
  - air__sio2 [10]
  - sio2__None [11]
  - sin__sio2 [12]
  - air__sin [13]
  - air__None [14]
----------------------------------------
Mesh:   palace-sim-microstrip/palace.msh

# Static PNG
sim.plot_mesh(show_groups=["metal", "P"])

pyvirtualdisplay not available; continuing without Xvfb


2026-10-23 11:19:44.913 (   5.100s) [    7FB95A161B80]vtkXOpenGLRenderWindow.:1460  WARN| bad X server connection. DISPLAY=

png

Run simulation on GDSFactory+ Cloud

# Run simulation on GDSFactory+ cloud
results = sim.run()

  palace-e7930970  [####################] 100%  complete  elapsed 2m 10s


Extracting results.tar.gz...
Downloaded 13 files to /home/runner/work/IHP/IHP/docs/sim-data-palace-e7930970

# Show S-parameter results
print(results)

SParams(2 ports [e1, e2], 300 freq points, 4 S-parameters)

# Plot S-parameters
results.plot()

png