Space Modulation

The modulation profile with a uniform or user-supplied spatial distribution of amplitude and phase. You can set different space modulation parameters to permittivity and electrical conductivity.

The space modulation is given by $A_s(r) = A_0(r) e^{i \psi(r)}$.

Space Modulation Amplitude

amplitude ($A_0$): Amplitude of space modulation. To obtain a uniform space modulation throughout the medium, set a real value in the edit box. Or upload a user-supplied amplitude distribution HDF5 dataset.

Type: floating-point number

• Unit: It takes the unit of whatever is being modulated.
• Constraint: greater than or equal 0
• Default: 1

To generate a HDF5 dataset in a correct shape, create a SpaceModulation (opens new window) object using the Python interface and use the to_hdf5(filename) (opens new window) method.

Space Modulation Phase

phase ($\psi$): Phase of space modulation. To obtain a uniform phase throughout the medium, set a real value in the edit box. Or upload a user-supplied phase distribution HDF5 dataset.

Type: floating-point number

• Unit: rad or degree (default)
• Default: 0

To generate a HDF5 dataset in a correct shape, create a SpaceModulation (opens new window) object using the Python interface and use the to_hdf5(filename) (opens new window) method.

Interpolation

interp_method: Interpolation method used to obtain the values at spatial locations on the Yee grid.

Options:

• nearest (default)
• linear PECMedium, AnisotropicMedium, FullyAnisotropicMedium, Medium2D, CustomAnisotropicMedium.

Notes

• The time modulation is given by $A_t(t) = A e^{i \phi - 2 \pi i freq0 t}$.
• The full space-time modulation is $A(r, t) = Re[A_t(t) A_s(r)]$.
• Currently, these mediums DO NOT support space-time modulation:
  • PECMedium
  • Anisotropic Medium
  • Custom Anisotropic Medium
  • Fully Anisotropic Medium
  • Medium2D
• Make allow_gain=True to set space-time modulation for dispersive medium.
• Nonlinearity and Space-Time Modulation are not simultaneously supported.
• The value of $A(r, t)$ must be higher than medium permittivity.

Related Content:

• Applying time modulation to materials (opens new window)
• Modeling dispersive materials (opens new window)