ANTENNA RADIATION PATTERN CONTROL USING CHARACTERISTIC MODE ANALYSIS

Abstract

Antenna integration is increasingly demanded for high system capacity and versatile functionalities. Multiple antennas and sophisticated radio frequency modules are installed together in communication systems. The radiation patterns of antennas can be seriously distorted due to the strong mutual coupling between closely placed antennas as well as the asymmetric operating environment, which may degrade the performance of the entire communication system. The antenna system is analyzed using characteristic mode analysis (CMA). Different antenna structures can support different sets of orthogonal modes with characteristic currents and modal radiation patterns. Useful information of both desired and undesired modes contributing to radiation is provided by CMA. The final radiation pattern of the antenna can be controlled by incorporating the desired modes and/or suppressing the undesired modes. Reactive loading and metasurfaces are adopted to control the radiation patterns. The proposed methods are promising for wireless communication system design in the 5G and 6G.