tidy3d.components.microwave.data.monitor_data.MicrowaveModeDataBase

class MicrowaveModeDataBase

Bases: MicrowaveBaseModel

Base class for microwave mode data that extends standard mode data with RF/microwave features.

Parameters:

• transmission_line_data (Optional[TransmissionLineDataset] = None) – Additional data relevant to transmission lines in RF and microwave applications, like characteristic impedance. This field is populated when a MicrowaveModeSpec has been used to set up the monitor or mode solver.

• transmission_line_terminal_data (Optional[TransmissionLineTerminalDataset] = None) – Additional data relevant to transmission line terminals in RF and microwave applications, like characteristic impedance, voltage transformation matrix, and current transformation matrix. This field is populated when a MicrowaveTerminalModeSpec has been used to set up the monitor or mode solver.

• classes (This base class adds microwave-specific functionality to mode data)

• including

• data (- Transmission line) – current coefficients for transmission line analysis

• modes_info (- Enhanced)

• handling (- Group index)

• reordering (- Mode)

Notes

This is a mixin class that must be combined with mode data classes (ModeData or ModeSolverData). It uses super() to call methods on the mixed-in class, extending their functionality rather than replacing it.

The mixin should be placed first in the inheritance list to ensure its method overrides are used.

Attributes

alpha	The attenuation constant (real part of \(-\gamma\)).
beta	The phase constant (imaginary part of \(\gamma\)).
distance_40dB	Distance at which the field amplitude drops by 40 dB.
effective_relative_permittivity	Effective relative permittivity (real part of n_eff²).
free_space_wavenumber	The free space wavenumber (k_0) in rad/m.
gamma	The propagation constant with SI units.
group_velocity	Group velocity (v_g = c/n_group) in m/s.
mode_classifications	List of mode classifications (TEM, quasi-TEM, TE, TM, or Hybrid) for each mode.
modes_info	Dataset collecting various properties of the stored modes.
phase_velocity	Phase velocity (v_p = c/n_eff) in m/s.
terminal_fields	Field data for each terminal.
wave_impedance	Compute the wave impedance associated with the waveguide mode.
transmission_line_data
transmission_line_terminal_data

transmission_line_data

transmission_line_terminal_data

property terminal_fields

Field data for each terminal.

Returns:

Dataset containing Ex, Ey, Ez, Hx, Hy, Hz field components indexed by terminal_label, or None if transmission_line_terminal_data is not set.

Return type:

Optional[TerminalFieldDataset]

property modes_info

Dataset collecting various properties of the stored modes.

property mode_classifications

List of mode classifications (TEM, quasi-TEM, TE, TM, or Hybrid) for each mode.

property free_space_wavenumber

The free space wavenumber (k_0) in rad/m.

property gamma

The propagation constant with SI units.

In the physics convention, where time-harmonic fields evolve with \(e^{-j\omega t}\), a wave propagating in the +z direction varies as:

\[E(z) = E_0 e^{\gamma z} = E_0 e^{-\alpha z} e^{j\beta z}\]

where \(\gamma = -\alpha + j\beta\).

property alpha

The attenuation constant (real part of \(-\gamma\)).

Causes exponential decay of the field amplitude:

\[E(z) = E_0 e^{-\alpha z} e^{j\beta z}\]

Units: Nepers/meter (Np/m).

property beta

The phase constant (imaginary part of \(\gamma\)).

Determines the phase variation of the field:

\[E(z) = E_0 e^{-\alpha z} e^{j\beta z}\]

Units: radians/meter (rad/m).

property distance_40dB

Distance at which the field amplitude drops by 40 dB.

For a lossy transmission line, this is the distance where the signal attenuates by 40 dB:

\[d_{40\text{dB}} = \frac{40\,\text{dB}}{20 \log_{10}(e) \cdot \alpha} = \frac{40}{8.686 \cdot \alpha}\]

where \(\alpha\) is the attenuation constant in Nepers/meter.

Units: meters.

property effective_relative_permittivity

Effective relative permittivity (real part of n_eff²).

property phase_velocity

Phase velocity (v_p = c/n_eff) in m/s.

property group_velocity

Group velocity (v_g = c/n_group) in m/s.

property wave_impedance

Compute the wave impedance associated with the waveguide mode. The wave impedance is defined as:

\[Z_{\rm wave} = \frac{\int |E_t|^2 \, {\rm d}S}{2 P}.\]

where \(E_t\) is the transverse electric field and \(P\) is the complex power flow.