Mode-Counteraction Based Self-Decoupling in Circularly Polarized MIMO Microstrip Patch Array

• Published in: IEEE transactions on antennas and propagation Vol. 70; no. 10; pp. 9337 - 9346
• Main Authors: Lai, Qi Xuan, Pan, Yong Mei, Zheng, Shao Yong
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna arrays; Circular polarization; Circularly polarized (CP) antenna; Couplings; Decoupling method; Feeding; Microstrip; Microstrip antenna arrays; microstrip patch antenna (MPA); MIMO communication; multi-input multi-output (MIMO) antenna; Mutual coupling; Patch antennas; Probes; self-decoupling
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2022.3184508

A mode-counteraction-based self-decoupling method is proposed for the circularly polarized (CP) multi-input multi-output (MIMO) microstrip patch antenna (MPA) array. The array simply consists of two identical diagonal-fed rectangular MPAs, without any extra decoupling structure. It is found that by properly adjusting the patch dimensions and feeding positions, the orthogonal TM1, 0 and TM0, 1 modes can be simultaneously excited in the active MPA to generate the CP field. Meanwhile, the coupled <inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>-fields of the two modes in the adjacent passive MPA can counteract each other, generating a null-field region. When the feeding probe of the passive MPA is placed within the null-field region, no signal can be received at the port, and consequently, an extremely low mutual coupling of −59.4 dB is achieved, without scarifying any other radiation performance of the MPA. In addition, this self-decoupling method is also applicable to other types of MPA arrays and four-element MPA arrays, exhibiting great versatility and extensibility.