A concept for MIMO antennas on small terminals based on characteristic modes

In this paper, we present a concept for a MIMO antenna system on a small terminal platform. The concept is based on the selective excitation of different orthogonal characteristic modes on the chassis of the small terminal. Thereby the chassis of the mobile terminal itself can be effectively used as the MIMO antenna similar to the concept commonly applied to single port (single mode) antennas on mobile terminals. The different modes generate orthogonal radiation patters and are therefore suited to radiate de-correlated signals fed to the different antenna ports. Such modes can be excited selectively by certain sets of couplers distributed around the outer edges of the chassis. First stage numerical investigations show that coupling between the modes is low.