In recent years, transmitarray antennas have attracted growing interest with many antenna researchers. Transmitarrays combines both optical and antenna array theory, leading to a low profile design with high gain, high radiation efficiency, and versatile radiation performance for many wireless communication systems. In this book, comprehensive analysis, new methodologies, and novel designs of transmitarray antennas are presented. Detailed analysis for the design of planar space-fed array antennas is presented. The basics of aperture field distribution and the analysis of the array elements are described. The radiation performances (directivity and gain) are discussed using array theory approach, and the impacts of element phase errors are demonstrated. The performance of transmitarray design using multilayer frequency selective surfaces (M-FSS) approach is carefully studied, and the transmission phase limit which are generally independent from the selection of a specific element shape is revealed. The maximum transmission phase range is determined based on the number of layers, substrate permittivity, and the separations between layers. In order to reduce the transmitarray design complexity and cost, three different methods have been investigated. As a result, one design is performed using quad-layer cross-slot elements with no dielectric material and another using triple-layer spiral dipole elements. Both designs were fabricated and tested at X-Band for deep space communications. Furthermore, the radiation pattern characteristics were studied under different feed polarization conditions and oblique angles of incident field from the feed. New design methodologies are proposed to improve the bandwidth of transmitarray antennas through the control of the transmission phase range of the elements. These design techniques are validated through the fabrication and testing of two quad-layer transmitarray antennas at Ku-band. A single-feed quad-beam transmitarray antenna with 50 degrees elevation separation between the beams is investigated, designed, fabricated, and tested at Ku-band. In summary, various challenges in the analysis and design of transmitarray antennas are addressed in this book. New methodologies to improve the bandwidth of transmitarray antennas have been demonstrated. Several prototypes have been fabricated and tested, demonstrating the desirable features and potential new applications of transmitarray antennas.

The objective of this book is to introduce students and interested researchers to antenna design and analysis using the popular commercial electromagnetic software FEKO. This book, being tutorial in nature, is primarily intended for students working in the field of antenna analysis and design; however the wealth of hands-on design examples presented in this book along with simulation details, makes it a valuable reference for practicing engineers. The requirement for the readers of this book is to be familiar with the basics of antenna theory; however electrical engineering students taking an introductory course in antenna engineering can also benefit from this book as a supplementary text. The key strengths of this book are as follows: First, the basics of antenna simulation will be presented in a detailed, understandable, and easy to follow procedure through study of the simplest types of radiators, i.e. dipole and loop antennas, in chapters 2 and 3. This will build the fundamental knowledge a student would need in order to utilize antenna simulation software in general. Second, comparison between theoretical analysis and full-wave simulation results of FEKO are given for a variety of antenna types, which will aid the readers with a better understanding of the theory, approximations and limitations in the theoretical analysis, and solution accuracy. Third, and of paramount importance, is the visualization of the antenna current distribution, radiation patterns, and other radiation characteristics that are made available through full-wave simulations using FEKO. A proper analysis of the radiation characteristics through these visualizations serves as a powerful educational tool to fully understand the radiation behaviour of antennas