config.py

"""
Physical parameters for the CPW quarter-wave resonator.
All dimensions in SI units (metres).
"""
import math

# Geometry

CPW_LENGTH = 3.0e-3
CPW_STRIP_WIDTH = 10e-6
CPW_GAP = 6e-6
CPW_GND_WIDTH = 50e-6
SUB_THICKNESS = 500e-6
AIR_THICKNESS = 300e-6

# Material

SILICON_EPS_R = 11.68   #Wikipedia

# Analytic Estimate

EPS_EFF = (1.0 + SILICON_EPS_R) / 2.0
C_LIGHT = 299792458.0
F0_HZ = C_LIGHT / (4.0 * CPW_LENGTH * math.sqrt(EPS_EFF))

# Mesh Sizing
MESH_METAL_EDGE  = 2e-6     # refinement at conductor edges (where fields peak)
MESH_SUB_BULK    = 50e-6    # bulk substrate
MESH_AIR_BULK    = 100e-6   # bulk air

if __name__ == "__main__":
    print(f"Target f₀:     {F0_HZ/1e9:.4f} GHz")
    print(f"ε_eff:          {EPS_EFF:.3f}")
    print(f"Domain (mm):   {CPW_LENGTH*1e3:.1f} × {(CPW_STRIP_WIDTH + 2*CPW_GAP + 2*CPW_GND_WIDTH)*1e6:.0f}μm × {(SUB_THICKNESS+AIR_THICKNESS)*1e6:.0f}μm")