CST STUDIO SUITE used to design microstrip patch array

In this application-based article on printed arrays in WLANs, CST shows that by separating the design process into specific steps, optimisation is made less challenging. The design process is simplified with the help of the circuit and full-wave 3D solvers and optimisation tools in CST STUDIO SUITE. The goal in this particular example was to design an array with high directivity, low cost and low sidelobes, with this case showcasing good impedance matching in the 5.18-5.85GHz frequency range. The approach described in this article can also be used to design other types of array through the use of a different radiator or array layout.

The first step of designing the array is to design the individual element. For this example, a simple square patch antenna was used and was created directly in CST STUDIO SUITE. The patch is created on a double-layered substrate with an air gap and is placed inside an ABS box. Two parameters need to be optimised: the length of the patch, in order to adjust the resonant frequency of the patch and the depth of the air gap, in order to increase its bandwidth.

Once the individual patch has been designed, it then has to be incorporated into an array. In this case, the choice of box and patch type limits the possible layouts for the array, and so a 4x4 planar array is used. However, any arbitrary array shape can be imported as a text file containing the location of each element and the magnitude and phase of the feeding current.

Download and read the full CST application note, below.