Numerical Electromagnics Code
Many antenna simulations can take place in NEC or its derivatives, which is a set of code written FORTRAN around 1981. Modern versions accept antenna and ground-plane descriptions in a text file and can show graphical output of the results in antenna plots, or even in 3d visualizations. There are commercial versions available with useful features, and for those interested public versions can also be found but usually with much fewer features.
NEC for your Computer
There are many choices of versions of NEC to run on your computer. The following list is just to give you an idea of what is available and where to look, and does not endorse a particular product.
Commercial NEC Releases
Public NEC Releases
Overview of NEC Design Process
NEC was designed to work with punch card inputs. NEC applications of today are designed to accept a text input that matches the data fields available on the punchcards. For this reason it may be difficult to understand the organization of data fields for some types of inputs, so if you can find an application that tells you the data fields during input instead of using a plain text editor it can accelerate the learning process.
This tutorial will model a 3 element cubical quad antenna with XNEC2c for Linux. The NEC2 input file we create here should be compatible with popular NEC applications and the output should be similar.
(incomplete workshop article)