Decoupling of Two Co-Frequency Small Patch Array Antennas Using Meta surface Mantle Cloaking for Beam Steering Applications

In this study, the mantle cloaking method is utilized to eliminate strong mutual coupling between two compact co-frequency patch antenna arrays with orthogonal polarizations. The patches are reduced in size by 33% through the addition of two slots on the resonant edges, allowing a reduction in distance between elements and enabling beam steering. To mitigate the destructive effects of mutual coupling between elements, a thin metasurface cloak is placed on the top and bottom surfaces of the patches. The metasurface cloak exhibits capacitive reactance at the desired operating frequency and eliminates the inductive reactance caused by induced currents from adjacent patches, making the elements of the two arrays invisible to each other. Full-wave simulation is used to evaluate the performance of this cloak structure in terms of array radiation characteristics. Results show that adding the cloak increased array efficiency by 35% compared to the uncloaked case, with isolation between elements improving by over 24 dB at the operating frequency. Radiation patterns in the cloaked case demonstrate a 98.5% similarity to those of isolated arrays. The antenna gains in the cloaked case slightly decreased by 0.1 dB and 0.2 dB for arrays I and II, respectively, and the sidelobe levels increased by 0.5 dB and 0.2 dB compared to isolated arrays. These findings confirm that this metasurface cloak design successfully restores radiation characteristics of tightly coupled arrays similar to those of isolated arrays.