Mutual coupling reduction of dual-band printed monopoles using MNG metamaterial

In this paper, a μ-Negative metamaterial (MNG) is utilized for mutual coupling reduction between dual-band printed monopole antennas used in Multiple Input Multiple Output (MIMO). A dual-band MNG metamaterial is designed to specifically possess negative effective permeability at the two resonant frequencies where the antennas are operating. MNG is inserted between the two printed monopoles (back to back) to decrease the correlation between them. The printed monopole antennas were designed to operate in the Wireless Local Area Network (WLAN) bands 2.45 GHz and 5.2 GHz. Antenna characteristics such as, scattering parameters far-field radiation patterns with and without the presence of MNG are provided. The design of the MNG unit cell and its effective constitutive parameters are also provided. Design and simulations are conducted using Ansoft's HFSS software which is based on the Finite Element Method (FEM). The proposed technique achieved a 14 dB reduction in mutual coupling at 2.45 GHz and 13 dB at 5.2 GHz. A gain of 2 dB higher than the normal case at the second band is observed while it is maintained the same on the first band. Furthermore, the MNG based antenna system maintains a relatively low profile (16 mm) which is convenient for compact systems and hand-held devices.