Planar High-Gain MIMO Antenna Based on the Theory of Characteristic Modes

This paper presents a high-gain multi-input multioutput antenna without decoupling structure based on the theory of characteristic modes. The antenna consists of two planar antenna elements: a loop with a rectangular patch and a rectangular planar monopole located on the opposite edge of the ground plane. These two antenna elements can excite different modes on the ground plane, thus achieving high isolation without additional decoupling structure. The simulation results obtained from the calculations show that the isolation is over 20 dB with a peak value of 42.48 dB, and the gain total is greatly improved.