Running a Bulk Simulation

AN-SOF can import a sequence of input files to generate a corresponding sequence of output files, all without requiring user intervention during the process. The input files must adhere to the NEC format and have a .nec extension. The supported NEC commands for importing wires are described in the section: Importing Wires.

Output Data

The output data includes:

• Power Budget or RCS (Radar Cross Section).
• Input Impedances.
• Far Field and Near Fields.

All output data is provided in CSV format. For each NEC input file, AN-SOF generates an individual project containing .emm and .wre files (see File Formats). This allows each project to be opened separately after the bulk simulation is completed.

Initiating a Bulk Simulation

1. Navigate to the main menu and select Run > Run Bulk Simulation.
2. A prompt will appear, asking if you want to save changes in the current project, as the bulk simulation requires closing the currently open project.
3. A dialog box will be displayed, allowing you to select a directory and the input .nec files.
4. After selecting the desired files and clicking the Open button, the bulk simulation will begin. The input files will be imported and computed one after another in alphabetical order.

Generated Files

For an input file named “InputFile.nec”, the following files will be generated:

AN-SOF Project Files

• InputFile.emm: Main project file (can be opened with AN-SOF).
• InputFile.wre: Geometry data (wires, segments, connections).
• InputFile.txt: Comments.
• InputFile.cur: Current distribution.
• InputFile.pwr: Input and radiated powers, directivity, gain, etc.
• InputFile.the: Theta component of the far field.
• InputFile.phi: Phi component of the far field.
• InputFile.nef: Near electric field.
• InputFile.nhf: Near magnetic field.

Output CSV Files with Results

• InputFile_PowerBudget.csv: Input and radiated power, efficiency, gain, etc.
• InputFile_Zin.csv: Input impedances, VSWR, S₁₁, etc.
• InputFile_FarFieldX.csv: E-theta and E-phi far field components.
• InputFile_EFieldX.csv: Near electric field components.
• InputFile_HFieldX.csv: Near magnetic field components.

Note:

• “X” represents the frequency in Hz (e.g., X = 300000000 for a frequency of 300 MHz).
• A FarField, EField, and HField file will be generated for each frequency if a frequency sweep simulation has been configured.

Automating Parameter Variations

Bulk simulations automate the calculation process for multiple NEC files, even if they are unrelated, eliminating the need for manual calculations file by file. They are particularly useful for sequentially running calculations on NEC files generated with varying geometric parameters for an antenna. The results can then be analyzed by reading data from the generated CSV files.

For example, you can create a script to generate a sequence of NEC files for a Yagi-Uda antenna, where the spacing between its elements varies. To learn how to accomplish this and read the output data from the CSV files, refer to the following article: Element Spacing Simulation Script for Yagi-Uda Antennas.