A Simplified Design Approach and Its Application to Decoupling of 2-D MIMO Square Patch Antenna Systems

• Published in: IEEE antennas and wireless propagation letters Vol. 23; no. 6; pp. 1759 - 1763
• Main Authors: Liu, Qianwen, Zhu, Lei, Lu, Wen-Jun
• Format: Journal Article
• Language: English
• Published: New York IEEE 2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; Couplings; Decoupling; diagonal status; Microstrip; Microstrip antenna arrays; Microstrip antennas; microstrip line; Microstrip transmission lines; MIMO communication; multiple-input–multiple-output (MIMO) antenna system; Mutual coupling; Patch antennas; Resonators; square patch resonator
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2024.3368635

In this letter, a simplified design approach for 2-D multiple-input-multiple-output (MIMO) patch antenna systems is first presented, and then a new self-decoupling concept is proposed. By equally exciting a pair of degenerate modes in the square patch resonator, i.e., TM mn and TM nm , a diagonal distributed status that possesses identical field distributions along all four sides of the resonator is created. In this context, the mutual couplings between horizontal- and vertical-arrayed patch elements become consistent and thus the complex 2-D decoupling problem is effectively facilitated and simplified to a 1-D one. Thereafter, a microstrip line with two metallic pins at both ends connected to the patches is embedded between the patch and ground layers to reduce the mutual coupling. Then, a 1 × 2 MIMO antenna system with an extremely close edge-to-edge separation of 1mm (0.0111 λ 0 ) demonstrates that the proposed method can realize a remarkable isolation enhancement of 4.3-19.8 dB over the entire working band. Moreover, the 1 × 2 MIMO antenna system is extended to the 2 × 2 ones, thereby validating the unique feature of the diagonal status of resonant mode in full 2-D MIMO patch antenna system designs.