Photonics

Photonics

S-parameters

    • djihad-amina.djemmah
      Subscriber

      Hello,

      I would like to simulate a 2D structure, and calculate the S parameters.

      I would like to know please:

      1/what is the difference between ports and grating S parameters.

      2/ should the monitors be placed far from the surface of the material (d>>lambda)? i.e. is there a relation between the wavelength of the source used and the distance between the transmitting and reflecting monitors and the surface ?

      3/ to simulate a structure at infinity along the y-axis, it would be necessary to use the periodic boundary conditions? and the material must exceed the edges of the boundary conditions or it does not influence?


      Waiting for your reply,

      Thank you in advance

    • Kyle
      Ansys Employee

      1) Ports are for measuring the S parameters of waveguide modes for devices such as directional couplers or MMIs. Grating S parameters are for measuring the plane wave S parameters of periodic grating structures.
      2) Guidelines for placement of monitors can be found here: https://forum.ansys.com/discussion/24664/ansys-insight-how-close-can-monitors-be-to-other-objects
      Structures
      Structures do not interfere with monitors. It is ok to have a monitor at the interface of two structures, or have a monitor cross through several objects. However, there are some types of calculations (like far field projections) that require the monitor to be in a homogeneous material. In this case, the monitor should be at least one full mesh point away from the structures.
      3) If the structure and source are infinite in the y direction, the best approach would be to use a 2D FDTD simulation oriented in the x-z plane instead of periodic boundary conditions.
    • djihad-amina.djemmah
      Subscriber
      Hello Thank you for your reply.
      I have another question about retrieving the values.
      I calculated the S-parameters with grating S-parameters, and then I plotted them. after that I recovered the values from the curve (.txt) .
      The problem I have is that I have only 6 values after the decimal point which is not enough to extract the effective parameters (permittivity, permeability), I need more precision.
      Knowing that I use a rather fine mesh.

      So my question is , how can I do to get more than 6 values after the decimal?
      Waiting for your answer.
      Thank you in advance.

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