Contribution to performance improvement in antenna-system-design for advanced wireless communications

Abstract

The present thesis deals with antenna design for modern wireless devices. The main goal is then to contribute in the performance improvement of those communications systems. Hence, the thesis suggests and investigates new designs to overcome some wireless chal- lenges. Antenna pattern reconfiguration is the first subject treated. It concerns CPW-Fed monopole antennas where a simple approach is developed to achieve this purpose. Phase shifters are also key components in many advanced applications, hence they are deeply studied in this work and three novel designs have been proposed. Moreover, MIMO technique is very promising in recent technologies, however with the presence of antenna coupling the overall performances are drastically degraded. This challenge has also been tackled, and an efficient decoupling mechanism of closely spaced antennas is proposed.