Running a Bulk Simulation

AN-SOF is capable of importing a sequence of input files to obtain a corresponding sequence of output files, all without requiring any 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 here: Importing Wires.

The output data consists of power budget or RCS (Radar Cross Section), input impedances, far field, and near fields, all provided in CSV format. For each NEC input file, AN-SOF generates an individual project containing .emm and .wre files (see File Formats). This way, each project can be opened separately once the bulk simulation is completed.

To initiate a bulk simulation, navigate to the main menu and choose Run > Run Bulk Simulation. A prompt will appear, asking whether you want to save the changes in the current project, as the bulk simulation requires closing the currently open project. Subsequently, a dialog box will be displayed, allowing you to select a directory and the input .nec files. Upon selecting the desired files and clicking the “Open” button, the bulk simulation will commence, with the input files being imported and computed one after another in alphabetic order.

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

Files of the AN-SOF project

InputFile.emm > main file of the project (it 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

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

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

Bulk simulations serve the purpose of automating the calculation process for multiple NEC files, even if they are not directly related, eliminating the need for manual calculations file by file. Conversely, they are also useful for sequentially running calculations on NEC files generated with varying geometric parameters in an antenna. Subsequently, the results can be analyzed by reading data from the generated CSV files.

For instance, 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 understand how to accomplish this and read the output data from the CSV files, you can refer to the following link: Element Spacing Simulation Script for Yagi-Uda Antennas.