A Meta-Surface Antenna Array Decoupling (MAAD) Method for Mutual Coupling Reduction in a MIMO Antenna System

Abstract

In this paper, a method to reduce the inevitable mutual coupling between antennas in an extremely closely spaced two-element MIMO antenna array is proposed. A suspended meta-surface composed periodic square split ring resonators (SRRs) is placed above the antenna array for decoupling. The meta-surface is equivalent to a negative permeability medium, along which wave propagation is rejected. By properly designing the rejection frequency band of the SRR unit, the mutual coupling between the antenna elements in the MIMO antenna system can be significantly reduced. Two prototypes of microstrip antenna arrays at 5.8 GHz band with and without the metasurface have been fabricated and measured. The matching bandwidths of antennas with reflection coefficient smaller than −15 dB for the arrays without and with the metasurface are 360 MHz and 900 MHz respectively. Using the meta-surface, the isolation between elements is increased from around 8 dB to more than 27 dB within the band of interest. Meanwhile, the total efficiency and peak gain of each element, the envelope correlation coefficient (ECC) between the two elements are also improved by considerable amounts. All the results demonstrate that the proposed method is very efficient for enhancing the performance of MIMO antenna arrays.

Mutual Coupling Reduction in Patch Antenna Array Based on EBG Structure for MIMO Applications

“…A comparison among the reported antennas and this study is summarized in Table 4, in term of antenna dimensions, metamatrials type, number of the operating band, separation distance, and the maximum isolation between the antenna elements. From Table 4, it is proven that compared to all published results, the proposed antenna array with EBG structure exhibits relatively excellent isolation with respect to the antenna array in comparison to other published results [5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

“…To reduce the surface wave excitation in printed rectangular patch antenna the authors in [14] investigated mushroom like EBG structure to mitigate the mutual coupling between the radiating antenna elements. A suspended metasurface composed periodic square SRR was applied above the antenna array in [15] for mutual coupling reduction, the proposed metasurface has the ability to reject the unwanted radiation as well as reducing mutual coupling in array antenna. An UC-EBG structure was introduced on the top of the antenna layer for mutual coupling reduction and antenna array miniaturization was reported in [16].…”

Harmonic interference suppression within a multiple‐antenna system using integrated slender magnetic metamaterials

“…There have been many literatures on techniques of suppressing mutual couplings among identical antennas operating under the same harmonic (usually the fundamental harmonic, the first‐order harmonic), such as suspended metasurface, slotted meander‐line resonator, neutralization lines, electromagnetic band gap (EBG) structure, defective ground structures (DGS), and parasitic elements . These techniques only pay attention to the suppressing mutual couplings between identical antennas, which operating under the same mode at the same frequency.…”

Design of a Four-Element Mimo Antenna With Low Mutual Coupling in a Small Size for Satelitte Applications

“…Sun and Wei [17] have analyzed and designed 4×4 MIMOantenna systems in mobile phone for ISM (2.4 GHz) applications. A design approach for dual-element hybrid MIMO antenna arrangement for wideband applications is proposed in [18], and a Meta-Surface Antenna Array Decoupling (MAAD) Method for Mutual Coupling Reduction in a MIMO Antenna System is presented in [19] by introducing periodic split ring resonators (SRRs) on the metasurface.…”