Plotting 3D Far Field Patterns

The far-field can be visualized as a 3D plot by selecting Results > Plot Far-Field Pattern > 3D Plot from the AN-SOF main menu. This action will open the AN-3D Pattern application, where the radiation pattern is displayed in a 3D view, showcasing the radiation lobes with their intensities represented by a color scale.

Within the AN-3D Pattern application, access the Plot menu to select the Power Density, Directivity (numerical and in dBi), Gain (numerical and in dBi), Radiation Pattern (normalized to unity and to 0 dB), E-field, and Axial Ratio (dimensionless and in dB) (see Fig. 1). Each field metric can be decomposed into its linearly polarized components Theta (VP: Vertical Polarization) and Phi (HP: Horizontal Polarization), as well as its circularly polarized components Right (RHCP: Right-Handed Circular Polarization) and Left (LHCP: Left-Handed Circular Polarization). If the simulation involves plane wave excitation, the Radar Cross Section (RCS) can be plotted instead of directivity and gain.

The Axial Ratio pattern is defined as the ratio of the minor to major axis of the polarization ellipse. It equals 0 for a linearly polarized field and 1 for a circularly polarized field. While lobes in a 3D polar plot can only represent absolute values, the sign of the axial ratio, which determines whether the field is RHCP or LHCP, cannot be directly visualized here but can be observed in a 2D rectangular plot. However, the toolbar in the AN-3D Pattern application features buttons: Tot, VP, HP, RH, and LH for quick switching between the total field and its polarization components, facilitating polarization analysis.

The 3D graph can be rotated and moved by clicking the “3D Rotation” or “Move” buttons on the toolbar and then dragging the mouse with the left button pressed. Use the mouse wheel to zoom in or out. The AN-3D Pattern toolbar also includes an option to change the frequency and dynamically observe the changes in the radiation pattern lobes as a kind of animation (use the up-down arrow buttons next to the displayed frequency value).

Note

• If discrete sources were used as the excitation of the structure, the plotted far-field represents the total field.
• If an incident plane wave was used as the excitation, the plotted far-field represents the scattered field.

To access the Preferences dialog box in the AN-3D Pattern main menu, click on Edit > Preferences (refer to Fig. 2). This dialog box allows you to customize various options for the colored surface and mesh of the radiation lobes (see Fig. 3). Additionally, you can superimpose the wire structure onto the radiation pattern by selecting the Wires option in the “Show” box. You also have control over the graph’s scale and can display the main axes.

The radiation pattern cannot be directly exported from the AN-3D Pattern application. However, the far-field pattern for a specific frequency can be tabulated by navigating to the AN-SOF main menu > Results > List Far-Field Pattern and then pressing the “Export” button next to the displayed table to export the data to a CSV (Comma Separated Values) file.