A Pin-Loaded Self-Decoupling Method for MIMO Patch Antenna Array Based on Fringing-Field Reshaping

In this letter, a novel pin-loaded self-decoupling method is proposed based on the fringing-field reshaping of the TM11-mode circular patch antenna. At first, the primary cause of coupling is demonstrated to be attributed to the fringing field of radiating patch, and the conventional antenna pair under E-plane array arrangement always suffers from strong electric coupling, leading to poor isolation. Then, a shorting pin is strategically loaded to the coupling edge of each patch, by which the initial strong electric field density is strategically redistributed to be a local minimum, contributing to the significant isolation improvement. Furthermore, a prototype of the highly-isolated antenna pair is manufactured and measured. The results illustrate the achievement of high isolation over 20 dB and remained symmetric broadside radiation pattern. Finally, the proposed method is respectively demonstrated on the MIMO arrays with more radiators and asymmetrical configuration, showcasing its efficacy for the versatile decoupling.