In order to suppress the strong coupling between extremely close-range multiple-input multiple-output ( MIMO) antenna elements, a decoupling method is proposed to arrange MIMO antenna elements feeding position in an extreme adjacent distance where belongs to their weak electromagnetic field region. The weak electromagnetic field region is mainly generated by changing the feeding structure of the microstrip antenna. Firstly, a two-element MIMO antenna with an edge-to-edge distance of 1 mm (0. 011λ0 ,λ0 is the free-space wavelength at the center frequency of 3. 5 GHz) is proposed. The simulation and measurement results show that the proposed decoupling method can improve the isolation of the MIMO antenna by 42 dB in the operating frequency band. The isolation performance of the proposed antenna is much more obvious than that of the reference antenna. Furthermore, a three-element MIMO antenna is constructed by arranging the improved antenna elements along 120°. The experimental results show that the coupling suppression is greater than 30 dB in the working frequency band of 3. 45 ~ 3. 55 GHz; the maximum isolation is 52 dB at the center frequency of 3. 5 GHz. Moreover, the reflection coefficient of each antenna is not affected by the proposed decoupling structure. It is worth noting that the proposed decoupling method has a good application prospect as it does not need additional decoupling circuit and components compared to the traditional approach with respect to mutual coupling reduction.