Analysis and Design of Transmitarray Antennas - Abdelrahman, Ahmed H.

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Résumé :
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 ofa 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.

Biographie:
Ahmed H. Abdelrahman received B.S. and M.S. degrees from The Department of Electrical Engineering, Electronics and Communications, Ain Shams University, Cairo, Egypt, in 2001 and 2010, respectively, and he received a Ph.D. degree in engineering sciences from The Department of Electrical Engineering, University of Mississippi, University, MS, USA, in 2014. Dr. Abdelrahman is currently a research associate with the Antenna Research Group (ARG), in The Department of Electrical, Computer, and Energy Engineering, at The University of Colorado Boulder, Boulder, CO, USA. He also worked as a postdoctoral research associate for almost two years in The Department of Electrical and Computer Engineering at The University of Arizona, Tucson, AZ, USA. Additionally, he possesses over eight years of experience in Satellite Communications industry. He worked as a RF design engineer and a Communication System Engineer in building the low earth orbit satellite Egyptsat-1. His research interests include transmitarray/reflectarray antennas, mobile antennas, reconfigurable antennas, simultaneous transmit and receive (STAR) antennas, satellite communications, and thermoacoustic and millimeter-wave imaging. Dr. Abdelrahman was the recipient of the several prestigious awards, including the Third-Place Winner Student Paper Competition Award at the 2013 ACES Annual Conference, and the Honorable Mention Student Paper Competition at the 2014 IEEE AP-S International Symposium on Antennas and Propagation.