Central-Symmetry Decoupling Technique for Circularly-Polarized MIMO System of Tightly Packed Chinese-character Shaped Patch Antennas

This article presents a novel decoupling technique for the circularly polarized multiple-inputmultiple- output (CP-MIMO) system composed of Guoshaped patch antennas. A comparative study has been conducted on antenna performance as a function of packing distance before and after applying the technique. A prototype of two-element Guo-shaped patch MIMO at a small inter-element spacing of 12.5 mm has devised aiming for the 5G new radio n38 (2.57-2.62 GHz) applications. Simulation reinforced with experimental results confirmed the effectiveness of the proposed technique, whereas the two Guo-shaped patch elements packed in such small spacing can be operated independently. Both the envelope correlation coefficient and diversity gain are approaching their ideal values.