Modifying RIS Element Spacing (In Proportion to the Wavelength λ) from Sionna Source Code

This tutorial explains how to modify the RIS element spacing from the default value of λ/2 to a custom value proportional to the wavelength λ by directly editing the Sionna source code.

Note

Sionna ray-tracing tool does not provide a direct way to modify the RIS element spacing via its standard interface. However, it can be changed by manually editing the source code.

Warning

Before making any changes, it’s important to create a backup of the original ris.py file. This allows you to easily restore it if needed.

1. Locate the `ris.py` File

   • Navigate to the following path where the Sionna ray-tracing source files are located:

   C:\Users\your_user_name\AppData\Local\Programs\Python\Python311\Lib\site-packages\sionna\rt

   • Open the file ris.py for editing.

2. Modify the RIS Element Spacing

   Apply the following changes inside the ris.py file:

   • Search for:

     wavelength/tf.cast(2,

     (You should find three matches.)

     Replace all occurrences with:

     wavelength/tf.cast(x,

     where x is the new denominator so that the element spacing becomes λ/x instead of λ/2.

   • Search for:

     tf.cast(0.5, self._rdtype)

     (You should find three matches.)

     Replace all occurrences with:

     tf.cast(1/x, self._rdtype)

3. Save and Restart

   • Save the modified ris.py file.

   • Restart your Python environment to ensure that the changes take effect.