Defining Near Field Aperture from File

Import near field data from a .efe file and / or .hfe file to define a near field data aperture. Use the near field data aperture when defining an equivalent source or receiving antenna.

The .efe and .hfe files do not contain information regarding the coordinates system, frequency or number of points. As a result, you need to supply the above information to define the near field data aperture.
  1. On the Construct tab, in the Define group, click the  Field/current data icon. From the drop-down list select  Define near field data file structure.

    Figure 1. The Define near field data file structure dialog.
  2. In the Aperture data definition drop-down list, select one of the following:
    • Electric and Magnetic field
    • Electric field
    • Magnetic field
  3. In the Source type field, select one of the following:
    • Load an ASCII text file
      Note: The units are V/m for the E-field and A/m for the H-field.
    • Load from *.hfe file
  4. In the E-field file field, browse to the E-field file location.
  5. In the H-field file field, browse to the H-field file location
  6. In the Coordinate system field, select one of the following:

The physical location of the sample points and how they relate to the defined aperture can be specified.

  1. [Optional] Select the Also sample along edges check box to assume the outer sample points lie on the edges of the defined aperture.
    For multiple near field sources in a single model, sample points may not lie on any two aperture edges that share a common side. This results in two elementary dipoles with the same location and polarisation to be included, leading to incorrect results.
  2. For options Cylindrical or Spherical, select the Swap source and field validity regions check box if the fields on the inside of the region are equivalent to the calculated field values.
  3. In the Width (W) field, specify the aperture width.
  4. In the Height (H) field, specify the aperture height.
  5. In the Number of points along U field, specify the number of points along the U axis.
  6. In the Number of points along V field, specify the number of points along the V axis.
  7. In the Start reading from line number field, specify the first line number to be read in the file.
    Note: Comment lines and empty lines are not counted.
    For example, a file with 100 points per near field, the second block starts reading from line 101, regardless of any comment lines. If both electric and magnetic field data is read, the starting lines in the files are identical.
  8. In the Label field, specify a unique label for the near field data.
  9. Click Create to define the near field data and to close the dialog.