Document Type : Research Article
University of Tabriz, faculty of electrical and computer engineering
Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
This study investigates the effectiveness of mantle cloaking in isolating two densely packed patch antenna arrays with close operating frequencies. The cloak used is an elliptical metasurface consisting of vertical strips on a thin dielectric layer. This metasurface cloak reduces strong mutual coupling between adjacent elements of co-planar arrays by exhibiting capacitive reactance at the desired operating frequency and eliminating the inductive reactance caused by induced currents from adjacent patches. As a result, the elements of the two arrays become invisible to each other.
To enable beam steering, the size of the patches is reduced by 34% through the addition of two slots on the resonant edges. The performance of the arrays is evaluated based on impedance matching, isolation, gain, radiation patterns, and efficiency. The results indicate that the addition of the cloak increased array efficiency by 35% compared to the uncloaked case. Additionally, the isolation between elements improved by over 15 dB at the operating frequency. The radiation patterns in the cloaked case closely resembled those of isolated arrays, with a similarity of 98%. However, in the cloaked case, there was a slight decrease in antenna gain by 0.7 dB and 0.5 dB for Array I and Array II, respectively. Furthermore, the sidelobe levels increased by 0.7 dB compared to isolated arrays. These findings confirm that the designed metasurface cloak effectively replicated the radiation characteristics of closely spaced arrays, resembling those of isolated arrays.