# `FEKO`

 FEKO is a Method of Moments (MoM) tool that can be used to calculate the radiation pattern, impedance and gain of an antenna while mounted on some defined geometry. In addition, it can calculate the isolation or mutual coupling (S12) between pairs of antennas, the near fields around an antenna and the electric currents that flow on an antenna or the surrounding structure. The basic flow of performing a FEKO analysis consists of 1) Building a geometry for the antenna (example – a wire to represent the antenna) in CADFEKO or EDITFEKO 2) Building a geometry to represent surrounding geometry (for instance, can model an antenna on top of an airplane or an antenna on a supporting structure which will affect the antenna’s performance) in CADFEKO, EDITFEKO or an external tool 3) Meshing the Created Antenna and Surrounding Geometries (CADFEKO or EDITFEKO) 4) Requesting Solution Types and Setting Solution Parameters (CADFEKO or EDITFEKO) 5) Running the FEKO solver (FEKO) 6) Read in and interpret results using PostFEKO. These steps will be described in this FEKO tutorial. I will be using FEKO version 4.0 and FEKO Suite 5.4. For a more advanced tutorial, see Tutorial #2 - Blade Antenna on a Cylinder. First, lets click the CADFEKO button wherever we have FEKO installed. If you have everything set up properly, you’ll see a screen similar to that shown below. This is where we can build geometry using a fairly simple graphical user interface.

 The easiest way to learn this stuff is to play around with it. We’ll walk through a couple examples. The first, we’ll look at a simple wire dipole and calculate the impedance and radiation pattern. The first step is to make our antenna. Note that the default settings for all geometry lengths is meters. This can be altered by clicking Model->Model Unit and selected a different unit, if say, you prefer inches. Lets say we want a dipole antenna to operate at 600 MHz. The wavelength at this frequency is 0.5 meters, so a half-wavelength dipole would be 0.25 meters. We’ll first declare a variable called “Length” to represent this. Right-click on the “Variables” label in the Model Tree as shown below, and select “add variable”: The following window pops up, and we enter the length as 0.25 (the unit is meters unless we specified otherwise). Then click create, and the variable is saved in the Variables Tree. For now, that is all the variables we'll make. You can add as many expressions for variables as you want, and even define variables in terms of other variables if you feel like it. Now, we'll create the geometry of our antenna. Click the “create line” button on the far left side of the CADFEKO screen: A create line window pops up. We will place this dipole centered at the origin (x,y,z)=(0,0,0), with the length given by our declared variable “Length”. We will name it “dipole” in the label panel. Click create to create the dipole, then close to close the create line window. This is all the geometry we'll need to model a simple wire antenna. In the next section, we'll look at adding sources to the dipole, meshing, and requesting output from FEKO. Next: Sources and Meshing in FEKO