Mutual Coupling Reduction between Closely Spaced U-slot Patch Antennas by Optimizing Array Configuration and its Applications in MIMO

Multiple-input, multiple-output (MIMO) systems have received considerable attention over the last decade. There are some limitations when obtaining the most from MIMO, such as mutual coupling between antenna elements in an array. Mutual coupling and therefore inter-element spacing have important effects on the channel capacity of a MIMO communication system, its error rate, and ambiguity of MIMO radar system. There is a huge amount of research that focuses on reducing the mutual coupling in an antenna array to improve MIMO performance.;In this research, we focus on the antenna section of the system. Antenna design affects the performance of Multiple-Input-Multiple-output (MIMO) systems. Two aspects of an antenna's role in MIMO performance have been investigated in this thesis. Employing suitable an antenna or antenna array can have a significant impact on the performance of a MIMO system. In addition to antenna design, another antenna related issue that helps to optimize the system performance is to reduce mutual coupling between antenna elements in an array. Much research has focused on the reduction of mutual coupling.;In this research, the effect of the antenna configuration in array on mutual coupling has been studied and the main purpose is to find the array configuration that provides the minimum mutual coupling between elements.;The U-slot patch antenna is versatile antennas that because of its features like wide bandwidth, multi-band resonance and the ease of achieving different polarizations. This research first investigated the u-slot patch antenna, its features and capabilities. Second a CAD optimization to design a low profile, dual band U-slot patch antenna is provided. Designed antenna is a dual band antenna that is intended to work at 3.5 and 5 GHz and have sufficient gain of at least 3dB.;The effect of mutual coupling on MIMO systems is studied and then different array configurations were considered for two closely spaced U-slot patch antennas. Different configurations show different mutual coupling behavior. After modeling and simulation, the array was designed, implemented and finally tested in an anechoic chamber. These results are compared to both simulation and theoretical results and the configuration with minimum amount of mutual coupling was found. Some radar experiments also have been done to prove the effect of mutual coupling on radar performance.