Disk

The Disk Command

The Disk command allows you to create circular metallic structures, such as ground planes, circular patch antennas, or reflector elements. Like other surface tools in AN-SOF, it can be modeled as either a transparent wire mesh or a continuous solid sheet.

To open the tool, navigate to Draw > Wire Grid / Solid Surface > Disk.

Geometric Precision: Curved vs. Straight

When setting up your disk, you have two options for how the circular edges are handled:

• Curved Segments: This provides an exact mathematical representation of the disk’s curvature. It is generally recommended for high-frequency simulations where edge effects are critical.
• Straight Segments: This approximates the circle using a series of straight linear wires (creating a polygon). This can be useful for simplifying geometry when exporting to solvers that do not support curved entities.

Orientation and Positioning

To define the disk’s location and “tilt” in 3D space, you use the following parameters:

• Center Coordinates (Cx, Cy, Cz$): The precise origin point of the disk (Figs. 1 and 2).
• Radius: The distance from the center to the outer edge.
• Theta and Phi: These angles define the disk axis direction (the vector perpendicular to the surface). For a disk lying flat on the XY-plane, you would set Theta = 0 deg.

Defining the Facets

In the Attributes tab, you define the density of the disk by specifying the number of Radial and Azimuthal (circular) divisions.

• Radial Facets: The number of divisions from the center to the edge.
• Azimuthal Facets: The number of divisions around the $360^{\circ}$ circumference.

Grid vs. Solid Surface

• Wire Grid: Select Circular cross-section in the Attributes tab to create a “spoke and wheel” radial mesh.
• Solid Surface: Select Flat or Rectangular to create a solid circular sheet. AN-SOF will automatically use flat strips to fill the circular area completely.

Materials

In the Materials tab, you can assign the physical properties of the metal, such as resistivity (e.g., Copper or Aluminum), or apply a dielectric coating if the disk is insulated.