Patch

The Patch Command

A Patch in AN-SOF is a specialized tool for creating solid, rectangular conductive surfaces that lie parallel to the XY-plane ($z = \text{constant}$). Unlike a general plate, the Patch is specifically optimized for applications like microstrip antenna design.

Key Characteristics

• Structure: It is composed of flat or rectangular strips that automatically adjust their width to form a continuous, gapless metal sheet.
• Orientation: Always horizontal (parallel to the XY-plane).
• Primary Use Case: Modeling Patch Antennas on a substrate.
  • Requirement: To model a patch on a dielectric, you must set the Ground Plane to Substrate by navigating to the Setup tab > Environment panel.

💡 Tip

Patch vs. Plate: Use Patch when your structure is parallel to the ground and you are using the Substrate ground option. Use Plate if you need to model a rectangular surface in free space, above a real ground, or if the surface needs to be tilted or vertical.

Configuration Steps

To open the tool, go to Draw > Wire Grid / Solid Surface > Patch. The dialog box features three tabs:

1. Patch Tab: Define the geometry by entering the coordinates of two opposite corner points (X1, Y1) and (X2, Y2) at a specific height (Z) (Figs. 1 and 2).
2. Attributes Tab: Specify the Number of Facets.
   • If you enter 0x0, AN-SOF automatically calculates the density based on the highest frequency (10 segments per $\lambda$).
3. Materials Tab: Assign the resistivity (e.g., Copper) or coating for the metallic sheet.

Automatic Facet Calculation

When the facets are set to 0x0, AN-SOF ensures that the discretization is sufficient for electromagnetic convergence across your entire frequency sweep. This is particularly useful for broadband designs where the electrical size of the patch changes significantly.