Create a geometry in COMSOL using mph

[Ayoubdz19]

I'm trying to implement a Python script to design an M-by-N microstrip antenna array loaded with lumped elements using the mph library. I wrote this code (with the help of ChatGPT), but it seems that I can't create the geometry.

Has anyone faced this issue before?

Here’s a preview of my code:

#=====================================================================
import mph
import numpy as np

def create_microstrip_antenna(model, M, N, substrate_thickness, patch_length, patch_width, feed_width, frequency):
# Define constants
c = 3e8 # speed of light in m/s
epsilon_r = 4.4 # Relative permittivity of the substrate (for example, FR4)
h = substrate_thickness # height of the substrate
freq = frequency # operating frequency

# Calculate the effective dielectric constant
epsilon_eff = (epsilon_r + 1) / 2 + (epsilon_r - 1) / 2 * (1 + 12 * h / patch_width) ** (-0.5)

# Calculate the width of the patch
W = c / (2 * freq) * np.sqrt((2 * epsilon_eff + 1) / (2 * epsilon_eff))

# Create geometry for the antenna array
for i in range(M):
    for j in range(N):
        x_pos = i * (patch_length + feed_width)
        y_pos = j * (patch_width + feed_width)
        
        # Create a microstrip patch as a rectangle
        patch = mph.node.create('Rectangle')
        patch.set('width', patch_width)
        patch.set('length', patch_length)
        patch.set('xpos', x_pos)
        patch.set('ypos', y_pos)
        patch.set('height', substrate_thickness)
        patch.set('material', 'PEC')  # Perfect Electric Conductor for patch material
        
        # Create the feed (lumped element)
        feed = model.physics.create('LumpedElement', name=f'Feed_{i}_{j}')
        feed.set('xpos', x_pos + patch_length / 2)  # Center of the patch
        feed.set('ypos', y_pos + patch_width / 2)  # Center of the patch
        feed.set('size', feed_width)
        feed.set('value', 1)  # Example of a lumped element value (e.g., a 50-ohm impedance)

# Create boundary conditions (such as radiation boundaries)
model.physics.create('PerfectElectricConductor', name='PEC_Boundary')
model.physics.create('GroundPlane', name='Ground')

# Set material properties for substrate (FR4 as example)
substrate = model.material.create('Substrate')
substrate.set('permittivity', epsilon_r)
substrate.set('thickness', substrate_thickness)

# Create the frequency-domain study
study = model.study.create('freq')
study.set('frequency', freq)
study.run()

return model

def main():
# Initialize COMSOL model
# Lien avec Comsom
client = mph.start(port=2038)
# On charge le projet
model = client.load('./comsol_files/microstrip_patch_antenna.mph')
mj = model.java
physics = model / 'physics'
emw = model / 'physics/Electromagnetic Waves, Frequency Domain '

# Parameters for the antenna
M = 4  # Number of elements along X axis
N = 4  # Number of elements along Y axis
substrate_thickness = 1.6e-3  # Substrate thickness in meters (e.g., 1.6 mm)
patch_length = 5e-2  # Patch length in meters (e.g., 5 cm)
patch_width = 5e-2  # Patch width in meters (e.g., 5 cm)
feed_width = 1e-2  # Feed width in meters (e.g., 1 cm)
frequency = 2.45e9  # Frequency in Hz (e.g., 2.45 GHz)

# Create microstrip antenna with lumped elements
model = create_microstrip_antenna(model, M, N, substrate_thickness, patch_length, patch_width, feed_width, frequency)

# Save the model if needed
model.save('Microstrip_Antenna_Model.mph')

if name == "main":
main()
#=====================================================================