def sim_impedance(sim: Simulation):
"""
Get the characteristic impedance of a simulation.
"""
sim.run(csx=False)
ports = sim.ports
z0 = ports[0].impedance()
idx = array_index(sim.center_frequency(), sim.freq)
return np.abs(z0[idx])
from pyems.boundary import BoundaryConditions
freq = np.arange(4e9, 18e9, 1e7)
unit = 1e-3
sim = Simulation(
freq=freq,
unit=unit,
boundary_conditions=BoundaryConditions(
(("PML_8", "PML_8"), ("PML_8", "PML_8"), ("PML_8", "PML_8")), ),
)
dielectric = common_dielectrics["PTFE"]
length = 50
coax_rad = mil_to_mm(190 / 2) # RG-141
core_rad = (coax_core_diameter(
2 * coax_rad, dielectric.epsr_at_freq(sim.center_frequency())) / 2)
Coax(
sim=sim,
position=Coordinate3(0, 0, 0),
length=length,
radius=coax_rad,
core_radius=core_rad,
shield_thickness=mil_to_mm(5),
dielectric=dielectric,
propagation_axis=Axis("x"),
port_number=1,
excite=True,
feed_shift=0.3,
ref_impedance=50,
)