A Study of Folded Monopole Antenna Close to Metal Object by Using Characteristic Mode Analysis

Two types of folded monopole antennas with different input impedance have been studied to achieve an antenna with robustness to metal objects for wireless communication in a space enclosed by metal objects. In this study, we analyze the change in the input impedance owing to the proximity of the metal plates to the antenna in terms of mode current and mode weighting coefficient calculated using the characteristic mode analysis.