Excitation by an Incident Field

When you want to simulate how an antenna or a metallic structure (like an aircraft or a tower) reacts to external electromagnetic waves, such as for Radar Cross Section (RCS) or scattered field analysis, you use an incident field.

To configure this in AN-SOF:

1. Navigate to the Setup tab.
2. Locate the Excitation panel.
3. Select the Incident Field radio button (Fig. 1).

Important Note on Discrete Sources

If you have previously defined discrete sources (voltage or current sources) on specific wire segments, AN-SOF will ignore them once the Incident Field option is active. The structure will be treated as a passive scatterer reacting only to the external plane wave.

Note

When an incident plane wave is used as the excitation, the calculated far-field and near-field results represent the scattered fields. The resulting radiation pattern is the scattered field pattern, observed in the far-field region where the scattered field amplitude decays with the inverse of the distance (1/r), and the scattered power density decays with the inverse square of the distance (1/r²) from the structure.