Plotting 2D Far Field Patterns

The radiation pattern can be visualized as a 2D rectangular plot by selecting Results > Plot Far-Field Pattern > 2D Rectangular Plot from the main menu. This action will open the Radiation Pattern Cut dialog box (Fig. 1), where two plot types are available:

• Conical Plots: Generated with a fixed Theta and variable Phi.
• Vertical Plots: Created with a fixed Phi and variable Theta.

Select a radiation pattern cut and click OK to launch the AN-XY Chart application (Fig. 2), where the radiation pattern is plotted against Phi for conical plots (fixed Theta) or against Theta for vertical plots (fixed Phi).

Within the AN-XY Chart app, access the Plot menu to graph various parameters, including Power Density, Directivity, Gain, E-field, and Axial Ratio. This menu also allows you to represent these metrics in decibels (dBi for directivity and gain) and decompose them into linearly polarized components: Theta (VP: Vertically Polarized) and Phi (HP: Horizontally Polarized), as well as circularly polarized components: Right (RHCP: Right-Handed Circularly Polarized) and Left (LHCP: Left-Handed Circularly Polarized). The app’s toolbar features buttons: Tot, VP, HP, RH, and LH for quick switching between the total field metric and its corresponding polarization components. For instance, you can plot the total gain in dBi or decompose it into its Theta (VP), Phi (HP), Right (RHCP), or Left (LHCP) components to analyze antenna polarization characteristics. In the case of plane wave excitation, where the antenna is receiving or the metallic structure is scattering electromagnetic waves, the Radar Cross Section (RCS) will be plotted instead of directivity and gain.

The Axial Ratio is defined as the ratio of the minor axis to the major axis of the polarization ellipse. It ranges from 0 to 1 in absolute value and can also be plotted in decibels. A circularly polarized field exhibits an axial ratio of ±1 (or 0 dB), while a linearly polarized field has an axial ratio of zero. A positive (negative) axial ratio indicates a right-handed (left-handed) polarized field.

The far-field pattern can also be visualized in a 2D polar chart by selecting Results > Plot Far-Field Pattern > Polar Plot 1 Slice from the AN-SOF main menu (refer to Fig. 3). This action will launch the AN-Polar app, which displays information such as maximum radiation, beamwidth, and front-to-rear/back ratios.

The AN-Polar app also features a toolbar with buttons: Tot, VP, HP, RH, and LH that enable the decomposition of the plotted metric into its polarization components.

To plot two slices of a 3D far-field pattern on the same polar chart, navigate to Results > Plot Far-Field Pattern > Polar Plot 2 Slices in the AN-SOF main menu. A dialog box will appear, allowing you to select the two slices. You can choose from two vertical slices, two conical slices, or vertical-conical combinations (see Fig. 4).

Clicking on a point in the polar curve will display the corresponding value of the represented metric and the polar angle.