tidy3d.plugins.smatrix.CoaxialLumpedPort

class CoaxialLumpedPort

Bases: AbstractLumpedPort, AbstractAxesRH

Class representing a single coaxial lumped port.

Parameters:

• name (str) – Unique name for the port.

• impedance (Union[complex, ImpedanceSpec] = 50) – Reference port impedance in ohms. Accepts a plain real number (e.g. 50) for a purely resistive load, or an ImpedanceSpec for a complex-valued impedance (which also requires a measurement frequency). Passing a complex scalar with a non-zero imaginary part raises a validation error; use ImpedanceSpec instead.

• num_grid_cells (Optional[PositiveInt] = 3) – Number of mesh grid cells associated with the port along each direction, which are added through automatic mesh refinement. A value of None will turn off automatic mesh refinement.

• enable_snapping_points (bool = True) – When enabled, snapping points are automatically generated to snap grids to key geometric features of the lumped port for more accurate modelling.

• center (tuple[float, float, float] = (0.0, 0.0, 0.0)) – [units = um]. Center of object in x, y, and z.

• outer_diameter (PositiveFloat) – [units = um]. Diameter of the outer coaxial circle.

• inner_diameter (PositiveFloat) – [units = um]. Diameter of the inner coaxial circle.

• normal_axis (Literal[0, 1, 2]) – Specifies the axis which is normal to the concentric circles.

• direction (Literal['+', '-']) – The direction of the signal travelling in the transmission line. This is needed in order to position the path integral, which is used for computing conduction current using Ampère’s circuital law.

Note

Only purely resistive impedances are supported. Providing an impedance with a non-zero imaginary part raises a validation error. For complex impedance support, use LumpedPort instead.

Example

>>> port1 = CoaxialLumpedPort(center=(0, 0, 0),
...             outer_diameter=4,
...             inner_diameter=1,
...             normal_axis=2,
...             direction="+",
...             name="coax_port_1",
...             impedance=50
...         )

Attributes

injection_axis	Required for inheriting from AbstractTerminalPort.
main_axis	Required for inheriting from AbstractAxesRH.
center
outer_diameter
inner_diameter
normal_axis
direction
impedance
num_grid_cells
enable_snapping_points
name

Methods

compute_current(sim_data)	Helper to compute current flowing through the port.
compute_voltage(sim_data)	Helper to compute voltage across the port.
to_current_monitor(freqs[, snap_center, grid])	Field monitor to compute port current.
to_load([snap_center])	Create a load resistor from the lumped port.
to_source(source_time[, snap_center, grid])	Create a current source from the lumped port.
to_voltage_monitor(freqs[, snap_center, grid])	Field monitor to compute port voltage.

center

outer_diameter

inner_diameter

normal_axis

direction

property main_axis

Required for inheriting from AbstractAxesRH.

property injection_axis

Required for inheriting from AbstractTerminalPort.

to_source(source_time, snap_center=None, grid=None, **kwargs)

Create a current source from the lumped port.

to_load(snap_center=None)

Create a load resistor from the lumped port.

to_voltage_monitor(freqs, snap_center=None, grid=None)

Field monitor to compute port voltage.

to_current_monitor(freqs, snap_center=None, grid=None)

Field monitor to compute port current.

compute_voltage(sim_data)

Helper to compute voltage across the port.

We arbitrarily choose the positive first in-plane axis as the location for the path. Any of the four possible choices should give the same result.

compute_current(sim_data)

Helper to compute current flowing through the port.

The contour is a closed loop around the inner conductor. It is positioned at the midpoint between inner and outer radius of the annulus.