EMI Modeling for Antenna-Chassis System Using Characteristic Mode Analysis

Characteristic mode (CM) analysis has been widely used in antenna geometry design, antenna location optimization, and feeding positions, etc. CM analysis has seldomly been used in electromagnetic interference (EMI) modeling. Meanwhile, interactions between the antenna and the vehicle body were modeled with full-wave simulation, but the coupling mechanism has been veiled. In this paper, characteristic mode analysis is applied into the vehicle body to better understand the coupling mechanism of the vehicle modes and the antenna-chassis coupling mechanism. A few typical modes of the vehicle body are discussed first, and how to excite a specific mode is also investigated by looking at the eigen-current and eigen-charge distributions. This paper potentially provides a guideline in tackling EMI problems using CM analysis.