A Closely Spaced Multi-element Self-Isolated MIMO Antenna Array

A novel decoupling technique for multiple-input multiple-output (MIMO) antenna array is presented in this paper. Unlike the conventional method of using additional circuits for mutual coupling suppression, a self-decoupling method is employed. The proposed method makes use of the fundamental TM01 mode on the excited element and the orthogonal TM20 mode on the non-excited element. This can be achieved by extending the radiating edge of the patch using a meander-line structure. The feasibility of this decoupling method has been demonstrated in an H-plane coupled 1 × 3 array with an edge-to-edge element spacing of 0.016 λ at the center operating frequency. Good operation characteristics in terms of impedance matching, isolation, as well as MIMO diversity performance are obtained.