# Pole Residue

PoleResidue represents the converted loss-tangent medium shown after using Convert to Loss tangent from a dispersionless Medium.

This converted model is based on FastDispersionFitter.constant_loss_tangent_model (opens new window), which returns a tidy3d.PoleResidue (opens new window).

# Name

name: Optional unique name for the medium.

# Type

type: Medium model used by this material entry.

  • Options: Pole Residue

# Color

color: Display color used for the medium in the GUI.

  • Type: color
  • Default: automatically assigned by the GUI

# General Properties

eps_real: Real part of the permittivity used to fit the constant loss tangent model.

  • Type: float number
  • Default: inherited from the original Medium permittivity

loss_tangent: Loss tangent used to fit the dispersive PoleResidue model.

  • Type: float number
  • Constraint: greater than or equal to 0

max_num_poles: Maximum number of poles allowed in the fitted model.

  • Type: integer
  • Constraint: greater than 0
  • Default: 5

eps_inf: Relative permittivity at infinite frequency generated by the fitted PoleResidue model.

  • Type: float number
  • Unit: unitless

poles: List of pole-residue pairs generated by the fitted PoleResidue model.

  • Type: list
  • Unit: rad/s

# Advanced

set_from_global_frequency: Toggle whether the frequency range is set from the Global Settings frequency range.

  • Options:
    • True: Use the global frequency range and disable manual frequency range inputs.
    • False: Manually set frequency_range.

frequency_range: Frequency range where the fitted model should approximate a constant loss tangent response.

  • Type: two float numbers
  • Unit: Hz, kHz, MHz, GHz, THz, or other available frequency unit
  • Required field

allow_gain: Toggle whether the medium is allowed to be active.

  • Options: True/False
  • Default: False

NOTE

The displayed eps_inf and poles are generated from eps_real, loss_tangent, frequency_range, and max_num_poles.

WARNING

After conversion from Medium, the GUI changes the type to Pole Residue with no option to revert automatically.

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