MIMO LTE antenna design for laptops based on theory of characteristic modes

In this paper the theory of characteristic modes is employed to find eigenvalues and current distributions of all relevant modes on a monocoque laptop chassis in the frequency range below 1 GHz. Based on these results a novel type of antenna (inductive coupler), located in the slot between the lid and the base part of the laptop, which exploits one of the characteristic modes is introduced and its performance optimized for the LTE low- and mid-band frequency range. In order to design a MIMO antenna system an additional, conventional antenna (capacitive coupler) is placed at the top of the laptop's lid. Both antennas excite mutually orthogonal current distributions on the laptop's chassis which results in an excellent MIMO antenna performance.