Analysis and design of antennas for wireless communications

Abstract

During the last couple of decades, telecommunications, and information technology in general, have witnessed important developments. There is today a general trend for multimedia communications (e.g. data, voice, photos, and video) and a growing demand for high data rate links between communication systems with increased contraints on mobility and compactness. Moreover, for a nomadic or sedentary use, wireless radio technologies like bluethood, WiFi, 3 G or MiMax, Ultra Wide Band (UWB) technologies are a big success. To meet this growing need for high rate wireless communcation systems, future equipment will require high performance antennas. Those will have to work over multifrequency bands or over a broad band. Furthermore, for aesthetic and practical reasons, they will also have to be integrate into radio systems, which require the design of compact and discrete structures complying with electromagnetic compatibility requirements with surrounding electronic circuits. To reach these objectives, we focused our research on thre-dimensional antennas that offer numerous degrees of freedom. But this kind of structures are complex due to the high number of design parameters they involve. The main objective of our thesis is the global modeling of active antennas, particulary, microsrtip path antennas with RF oscillators. Antennas and RF oscillators play an important role in Microwave integrated Circuits (MICs) and Monolithic MICs (MMICs) technology. This technology concerns many interesting civil and military applications such as WLAN, Bluetooth, UWB, cell phones, satellite communications, microwave ovens and many other industrial, medical and scientific applications. Computer aided design (CAd) tools are essential for optimizing the processus of fabrication of these structures and also for the prediction and analysis of their characteristics.