The following inverted-F antenna (IFA) model was created in FEKO to show how a model can be built, made parametric, and then optimized for use.
This particular model is on a substrate that is 100 millimeters wide by 150 millimeters tall. The IFA is located in an open area near the center of the top of the board with no copper fill below:
The antenna was put on an Isola Group FR408HR board that has the advantageous design features of being relatively low loss and fairly inexpensive. The model is fully parametric, making it easy to manipulate and optimize the parameters to tune the antenna for a final design.
A couple of notes:
- The IFA is extremely ground dependent. Therefore, significant changes to the model may be needed depending on the size of the ground.
- The model includes a few vias along the front edge. More vias will likely be needed to reduce impedance anomalies caused by the two layers not being tied together.
The first thing to do before using the optimizer is to determine the frequency of operation. Based on that frequency:
- Adjust the length of the IFA. Taking into account the height of the antenna above the ground plane, it should be slightly less than λ/4.
- Adjust the height.
- Make a few initial runs adjusting the height and length to get close to the desired frequency of operation.
- Set the parameters that you are adjusting to make those the initial starting point for the optimizer.
ARSI 
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