Abstract

This work aims to show that the use of different radiation patterns within the same antenna array in multiple-input multiple-output systems is beneficial in scenarios where there is uncertainty on the angle of arrival of the desired signal. We propose a completely planar design, based on patch antennas, and we deploy two different types of antennas with opposite radiation patterns (broadside and monopole-like). With this scheme, we guarantee a higher minimum of spectral efficiency values and better averaged performance than is obtained in configurations with equal radiation patterns. We also show that our strategy is the best option for any angle of arrival when the spatial diversity is limited by the number of elements and the distance between radiating elements is small, which is a common limitation in relatively small terminals.