A Self-Decoupling Method for Antenna Arrays Using High-Coupling Characteristic Modes

In this work, a self-decoupling method is proposed for multi-antenna systems by suppressing coupling modes identified through characteristic mode analysis. Antennas are modified to break high-coupling modes while preserving radiating modes, thereby enhancing isolation. The proposed method has been validated through an example of two metasurface (MTS) antennas placed side by side. Effective suppression of high-coupling modes was achieved by etching slots on the MTS, resulting in an isolation improvement of over 10 dB between the two antennas without the need for additional decoupling structures. The proposed decoupling method is applicable for various antenna systems.