Flat Ring

The Flat Ring Command

The Flat Ring command is used to create an annular (ring-shaped) surface, essentially a disk with a circular hole at its center. This is a common geometry for specialized ground planes, circular loop-fed antennas, or parasitic ring elements.

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

Geometry and Orientation

To define the physical placement and size of the ring, you provide the following parameters in the Flat Ring tab:

• Center Coordinates (Cx, Cy, Cz): The origin point of the ring’s center (Figs. 1 and 2).
• Radii: You must define both the Inner Radius (the size of the central hole) and the Outer Radius.
• Orientation (Theta and Phi): These angles define the vector perpendicular to the ring’s surface (the ring axis). For example, setting Theta = 0 places the ring on the horizontal XY-plane.

Curvature: Curved vs. Straight

Like the Disk command, you can choose how the software handles the circular edges:

• Curved Segments: Recommended for maximum electromagnetic accuracy, as it uses the exact mathematical curvature of the ring.
• Straight Segments: Approximates the ring circles using a series of straight wire segments (polygonal approximation).

Attributes and Faceting

In the Attributes tab, you determine how the ring is “meshed” for the simulation engine:

• Facets: Define the density of the mesh using Radial (from the inner edge to the outer edge) and Azimuthal (around the circle) divisions.
• Wire Grid vs. Solid Surface:
  • Select Circular cross-section to create a wire mesh.
  • Select Flat or Rectangular to create a continuous, solid metal sheet. AN-SOF will automatically calculate the strip widths to ensure there are no gaps between the facets.

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 ring is insulated.