A Design of MIMO Antenna With High Isolation and Compact Size Characteristics

A method to significantly improve the isolation of multiple-input-multiple-output (MIMO) antenna is presented in this paper. The proposed design consists of multiple patches arranged in the H-plane configuration. Satisfactory isolation is obtained by using microstrip lines that are positioned along the radiating edges of the patches. The function of the decoupled lines is to excite an orthogonal polarization mode on the non-excited patch. A two-element array is fabricated to demonstrate the effectiveness of the proposed decoupling structure. The experimental results illustrate that the isolation of the 2-element MIMO antenna can be significantly improved by about 26 dB with an extremely small element spacing of $0.017 \lambda _{0}$ . Besides, the antenna exhibits good diversity performances. The decoupling method is also applicable to a multiple-element MIMO antenna. Compared to other related works, the proposed design has the smallest element spacing while achieving high isolation. The antenna can be used for 5.2 WLAN applications.