Mutual Coupling Compensation in Receive-Mode Antenna Array Based on Characteristic Mode Analysis

In this communication, the characteristic mode analysis (CMA) is applied to the analysis of mutual coupling in a receive-mode antenna array with geometric symmetry. Because CMA provides modes that incorporate a mutual coupling effect, CMA can be used to develop a method for compensating this mutual coupling effect. An understanding of the symmetries and underlying physical characteristics of the characteristic modes (CMs) of a receive-mode antenna can be used to intuitively explain the effects of incident signal polarization and incidence angle on the port signal. Using this knowledge, a mutual coupling compensation matrix (MCCM) is constructed by finding the CMs and Z-matrix of a metallic antenna array through a single simulation. The proposed method is validated by comparing MCCM-predicted with simulated port currents on a 1-D linear bowtie antenna array model. Further validation revealed that the proposed MCCM significantly reduced the compensation error and outperformed the commonly used open-circuit voltage-based MCCM in providing accurate direction-of-arrival estimation results.