Mutual Coupling Reduction in MIMO Microstrip Patch Array Using TM10 and TM02 Modes

• Published in: IEEE transactions on antennas and propagation Vol. 69; no. 11; pp. 7562 - 7571
• Main Authors: Lai, Qi Xuan, Pan, Yong Mei, Zheng, Shao Yong, Yang, Wan Jun
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna arrays; Decoupling method; Microstrip antenna arrays; Microstrip antennas; Microstrip patch antenna (MPA); MIMO communication; multi-input multi-output (MIMO) antenna; Mutual coupling; Patch antennas; Resonant frequency
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2021.3090520

A novel decoupling method is investigated for the multi-input multi-output (MIMO) microstrip patch antenna (MPA) array. This method makes use of the TM 10 and TM 02 modes, which are simultaneously excited in the rectangular MPA. It is found that by adjusting the frequencies of the two modes, their <inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>-fields coupled to the adjacent passive MPA can counteract each other to generate a specific null-field region. When the feeding position of the passive MPA is located in the null-field region, the MPA cannot be excited effectively, and hence an extremely low mutual coupling is obtained without requiring any extra decoupling structure. To validate the feasibility of this decoupling method, an E- and an H-plane-coupled <inline-formula> <tex-math notation="LaTeX">1\times 2 </tex-math></inline-formula> MIMO MPA arrays are respectively simulated, fabricated, and measured. The isolation of the E-plane-coupled array is enhanced from ~11 to 57 dB, while that of the H-plane-coupled array is improved from ~18 to 51 dB.