CoaxialLine

class pmrf.models.components.lines.coaxial.CoaxialLine(length: Any, d_in: Any = 0.00112, d_out: Any = 0.0032, dielectric: Any = <factory>, conductor: Any = <factory>, outer_conductor: Any = None, shield_thickness: Any = None, formulation: AbstractCoaxialFormulation = <factory>, *, name: str | None = None, metadata: Any = None)

Bases: AbstractImmittanceLine

Coaxial line defined by geometry and materials.

The default SchelkunoffCoaxialFormulation is the exact cylindrical solution. TescheCoaxialFormulation provides a Bessel-free approximation.

Example

import pmrf as prf
from pmrf.models import CoaxialLine
from pmrf.materials import BulkConductor, ConstantDielectric

phys_cable = CoaxialLine(
    d_in=0.9e-3,
    d_out=2.95e-3,
    dielectric=ConstantDielectric(ep_r=1.5, tand=0.0004),
    conductor=BulkConductor(sigma=5.8e7),
    length=0.5
)

freq = prf.Frequency(start=1, stop=20, npoints=101, unit='ghz')
s_phys = phys_cable.s(freq)
Parameters:

  • d_in (Param, default=1.12e-3) – Inner conductor diameter in meters.

  • d_out (Param, default=3.2e-3) – Outer conductor inner diameter in meters.

  • dielectric (AbstractDielectric, default=ConstantDielectric()) – The dielectric filling, which supplies both its permittivity and its permeability. A scalar permittivity or an (ep_r, tand) tuple is coerced into a ConstantDielectric; a magnetic filling sets that material’s mu_r.

  • conductor (AbstractConductor, default=BulkConductor()) – The inner conductor material. A scalar conductivity in S/m is coerced into a BulkConductor.

  • outer_conductor (AbstractConductor | None, default=None) – The shield material. None means the same material as conductor.

  • shield_thickness (Param | None, default=None) – Shield wall thickness in meters. None means an infinitely thick shield.

  • formulation (AbstractCoaxialFormulation, default=SchelkunoffCoaxialFormulation()) – The closed-form physics used to compute the immittance.

immittance(freq: Frequency) → ImmittanceResult

Calculates the frequency-dependent per-unit-length immittance.

Parameters:

freq (Frequency) – The frequency axis.

Returns:

The series impedance and shunt admittance vectors.

Return type:

ImmittanceResult

conductor: AbstractConductor

The inner conductor material

d_in: Param = 0.00112

Inner conductor diameter

d_out: Param = 0.0032

Outer conductor inner diameter

dielectric: AbstractDielectric

The dielectric filling

formulation: AbstractCoaxialFormulation

The underlying physics formulation

outer_conductor: AbstractConductor | None = None

The optional shield material; None reuses the inner conductor

shield_thickness: Param | None = None

The optional shield wall thickness in meters