As systems continue to grow, there may be unforeseen and undesirable outputs. A MIMO antenna does produce a strong directional signal yet there can also be similar strength signals produced in other directions. These signals are referred to as minor lobes. The signal with the most strength is called the major lobe. When designing an antenna array it is ideal to have one very strong major lobe and less significant minor lobes. Yet this is not always the case.
Example of lobes in 3D for a rectangular array
2D representation of lobes, major lobe is in red
Depending on the architecture, how close antenna array elements are together and even the input signal itself can vary the output. In some cases there can be equally strong lobes that both could be considered the major lobe. But this is undesirable and the most ideal output would be having an array that sends a strong signal in a particular direction.
For most of the software portion of this project, the focus is on simulating and optimizing the antenna array so that it will have an ideal output. Software like MATLAB offers great tools for simulation.
In MATLAB one can design an array, the elements, and use Simulink to create a beam . For the first semester, the focus was primarily using Simulink to design architecture to do so.
Simulink Model of Conventional Beamforming
Comparison between Noise signal with and without beamforming
Example of Beamforming with different phase and angle (25 degrees)
For the second semester, the focus was on array optimization and creating elements in MATLAB to aid in antenna design. This was accomplished by using MATLAB’s Phased Array toolbox and Antenna Designer.