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Technical FAQ

1. What are the minimum PC requirements?

Windows Vista/7/8/10/11. 2GHz CPU, 2GB RAM, 1GB free disk space.

2. Does AN-SOF support parallel processing?

No, it doesn’t. AN-SOF has been developed to run on home computers running Windows(R) OS, so numerical calculation strategies have been implemented to take care of the available RAM memory and at the same time obtain reliable results.

3. What is the upper frequency limit?

There is no theoretical upper limit for the frequency since the structure size is measured in wavelengths. So, we talk about a size limit in wavelengths instead of a frequency limit. The simulation requires solving a matrix equation of increasing order as the structure size is increased in wavelengths, so modeling large structures will require more computer memory and time on a particular PC.

4. Does AN-SOF support load impedances?

Yes, it does. Resistance, inductance, and capacitance elements can be added to the structure to model the connection of lumped load impedances.

5. Are near E- and H-fields available in tables and for exportation as Excel or Google Sheets files?

Yes, they are. The computed near E and H fields can be visualized in 2D and 3D plots as well as in tables and exported as CSV (Comma Separated Values) files. Cartesian, cylindrical and spherical near field components can be obtained.

6. Is the thin-wire grid model well suited for surfaces?

Although the Method of Moments (MoM) is specialized to thin wire structures in AN-SOF, metallic surfaces can also be modeled by means of equivalent wire-grids with reasonable accuracy. As a rule, the wire radius must be 1/4 of the separation between the wires in a grid. You will find a paper about equivalent wire-grid modeling here >.

7. Can I import NEC files into AN-SOF?

Yes. Most of the NEC commands are supported. Download NEC example files to import into AN-SOF from here >

8. Is AN-SOF based on a NEC engine?

No. AN-SOF is an independent implementation of the Method of Moments (MoM) for wire structures. NEC is an old Fortran calculation engine that has a lot of limitations. Many of these limitations have been removed in AN-SOF by implementing the so-called Conformal Method of Moments with Exact Kernel > in a completely new object-oriented C++ code. See further details here >

9. Can parametric design be done with AN-SOF, that is, run simulations with variable geometric parameters such as the separation between dipoles in an array?

Yes. Parametric design is possible by running a Bulk Simulation >. We prefer that the user chooses the programming language to generate a sequence of files in NEC format with one or more variable parameters. Calculations on these files can then be run automatically in bulk. Scilab > is a free numerical calculation software tool with which we can program scripts that generate multiple descriptions of an antenna with variable parameters. Download an example of a Yagi-Uda antenna with variable element spacing from this link >.

10. What types of PCBs and microstrip antennas can be simulated with AN-SOF?

Although AN-SOF was developed to simulate wire structures, we have been able to extend the calculation engine to also model PCBs and microstrip antennas that meet the following requirements:

  • The structure must have a single layer of dielectric substrate. Multiple layers are not supported.
  • When the substrate has a finite size, the traces must be separated from the edges by at least 5 times the width of a trace.
  • The dielectric substrate is backed up by a perfectly conducting ground plane that cannot be removed. Vias that go through the substrate and connect traces to the ground plane can be added to feed an antenna or PCB.
11. Can arrays be built quickly by duplicating and copying parts of a structure?

Yes. Go to main menu > Edit > Copy Wires > to duplicate or make the desired number of copies of the selected wires. There is also the Stack Wires command which allows us to repeat a design along a given direction. By using this command in combination with the Scale Wires > command we can quickly build Yagi-like arrays.

12. How does AN-SOF divide the wires into segments? Is a higher density of segments needed in tapered wires?

By default, AN-SOF calculates the minimum recommended number of segments for each wire depending on its length in wavelengths. Various convergence analyzes > show that 10 wire segments per wavelength is sufficient for most cases. Regarding tapered wires, in old algorithms like NEC it was necessary to increase the density of segments near the connections between wires when there is a radius jump. This is not necessary in AN-SOF as it is not NEC based. See the advantages of AN-SOF here >.

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