Design of a Miniaturized Symmetrical E-shaped MIMO Antenna withLow Coupling

In order to meet the demand of contemporary 5G mobile communication for miniaturized MIMO antenna systems, this paper proposes a symmetric E-shaped patch antenna. It is mainly realized by digging out the simple rectangular radiation patch, and etching four rectangular slots at the ground plane to widen the working bandwidth. The overall size of the antenna is 20 mm × 40 mm. However, there is current mutual coupling between the two radiation patches closely arranged up and down, which greatly affects the radiation effect of the antenna. Therefore, in order to reduce the coupling degree between each other, a 1 × 3 metamaterial (MTM) array structure is added between the two patches, in which the structure of the MTM unit is similar to a “concave” character. Simulation and real measurement of antennas using 3D electromagnetic simulation software HFSS and vector network analyzer, and the test results show that the proposed antenna is S11 <-10 dB in 5.32-6.02 GHz (relative bandwidth of 12.35%), the isolation degree S21 is above -18 dB throughout the operating frequency band, and the overall Envelope correlation coefficient (ECC) is less than 0.02 in the working band, which further confirms that the designed MIMO antenna has good isolation. The radiation pattern of the antenna is good, which is suitable for the basic requirements of 5G WLAN band.