Mutual Decoupling for Massive MIMO Antenna Arrays by Using Triple-Layer Meta-Surface

Abstract

The high isolation massive antenna arrays are the key devices in the base station of the future wireless communication systems. The challenge for the array application is how to reduce the coupling among the array elements. This paper introduces a new decoupling method for massive MIMO arrays with an innerelement distance of around half wavelength by using a triple-layer metasurface (TMS). The TMS comprises three identical surfaces. The waves reflected from the bottom metasurface (MS) and top two-layer MS have the same amplitudes and the opposite phases, which are canceled with each other. An example of 4×4 dualpolarized wideband microstrip array with a TMS is proposed to verify the decoupling method. The simulation and measurement show that the TMS can help reduce the coupling among the array elements to less than -24 dB in both the co-polarization and cross-polarization directions within 4.23-4.82 GHz. In the meanwhile, the radiation characteristics of the arrays with and without TMS are almost unchanged.INDEX TERMS Decoupling, dual-polarized, massive multiple-input multiple-output (MIMO) antenna array, triple-layer metasurface (TMS), wideband.

Decoupling for Millimeter-Wave Array Antennas Using Near-Field Shrinking Dielectric Superstrate

“…Yet, owing to the decoupling performance of mmwave arrays being sensitive to the distance between the array and metasurface, it is difficult to be used in mm-waves applications. In addition, the working band of the arrays in [13], [14], and [15] is narrower than the one in our work. The decoupling method in [16] can be used in mm-wave antennas.…”

“…However, it cannot be applied to mm-wave antennas. The TMS in [15] divides the space wave coupling into two parts with different propagation paths with the same amplitudes and opposite phases to enable cancellation with each other. Yet, owing to the decoupling performance of mmwave arrays being sensitive to the distance between the array and metasurface, it is difficult to be used in mm-waves applications.…”

“…The decoupling network is an effective method for mutual coupling suppression [13], which commonly operates within a narrow bandwidth. The metasurface is another effective decoupling method, which is typically loaded above the arrays with a distance [14]- [15]. However, the mm-wave arrays are very sensitive to the distance between the metasurface and the array.…”

Antenna Array Diversity Evaluation Under Multipath Environments With Digital Beamforming

“…As a conclusion, higherorder aperiodic arrays have been shown efficient for mitigating inter-user interference by reducing channel correlation. Table I compiles the main contributions and applications from the references [9][10][11][12][13][14][15][16][17][18][19], which also includes the previously discussed papers from the Introduction.…”