Anisotropic Metamaterial Based Decoupling Strategy for MIMO Antenna in Mobile Handsets

Improving the isolation between Multi-input Multi-output (MIMO) antenna elements in a mobile handset is a challenging topic in 5G communication time in order to achieve high data rate. Conventional decoupling methods for MIMO antennas are usually based on changing or neutralizing the interacted current, whereas the concept of controlling electromagnetic fields is seldom considered in the decoupling techniques. In this letter, a novel decoupling strategy is proposed for MIMO antennas in mobile handsets. The anisotropic non-resonant closed-rings metamaterials is arranged in the space between antenna elements to re-shape the radiation pattern and to improve the isolation. As the proof of concept, a prototype of 8-element MIMO antennas is demonstrated. The simulation and experimental results indicate this decoupling method can improve the isolation to the 10 dB level at the limitation of 0.08-wavelength distance at sub-6GHz frequency range.