MIMO Antenna Elements Effect on Chassis Modes

In this paper, a 4-element printed multiple-input-multiple-output (MIMO) loop antenna having a bandwidth of 400 MHz is proposed. The effect of the MIMO antenna on the chassis modes system is analyzed via the theory of characteristic modes (TCM), and it is shown that chassis CM are not enough for the full analysis. A defected-ground-structure (DGS) is also proposed to enhance the isolation between the antenna elements by blocking the coupling modes.