Capabilities and fundamental limitations of multi-mode antennas in an array environment

A numerical study on beam-steering arrays of multi-mode antenna (MMA) elements is presented. Each MMA is capable of supporting multiple orthogonal modes (e.g. differential and common modes) to increase the beam coverage or angular diversity of the array antenna. The goal is to investigate how the performance of such MMAs in terms of maximum scan range and bandwidth is modified by the array mutual coupling environment, in particular for dense regular arrays of connected MMA elements with an element spacing smaller than half wavelength. The final results for sparse irregular arrays are presented and considered to be the favorable array environment.