On the reduction of mutual coupling between stacked patches by exploiting the properties of the parasitic patch

In this paper the analysis of mutual coupling between stacked patch antennas is carried out. To this aim, the level of mutual coupling has been studied in relation with an air gap between the driven and parasitic patch. The thickness of this gap defines the operational region of the antenna in terms of bandwidth, gain and radiation pattern. For certain parameters of the stacked patches, it has been noticed that a dip appears in the mutual coupling characteristics. A detailed study of this phenomenon for both linear and planar arrays configurations has been carried out. Since this dip in the mutual coupling depends mostly on the resonant frequency of the parasitic patch, it can be used to reduce the mutual coupling in the operational frequency bandwidth of the antenna. This reduction has been validated both by simulations and measurements for the case of linear arrays.