Wideband Microstrip Antennas Using Electromagnetic Bandgap Structures

In this thesis, I performed a study on the electromagnetic behaviors of an Electromagnetic Bandgap (EBG) structure with a specific set of parameters, and explored the effects of the geometrical parameters on its bandgap, which can be a stepping stone for designing future EBG structures with desired electromagnetic bandgaps. Later, the performance of a microstrip patch antenna when its ground plane is replaced by a lattice of the studied EBG units is investigated. This led to a noticeable bandwidth and gain enhancement, which motivated me to perform a parameter study to seek further bandwidth improvement. No restriction was placed on the range of parameters, and wider band antennas were observed when parameters fell outside the band gap requirements. Furthermore, I developed methods and designs that can be used to reduce the antenna size and weight by applying some structural modifications. I introduced two antennas, which I named "the puck antenna" and "suspended EBG-backed antenna". The presented simulation results describe the performance of these antennas. The use of an EBG structure as the ground plane of a microstrip patch antenna is shown here to enhance the gain of the antenna. This motivated me to look for further gain enhancement by placing a dielectric cover on top of the antenna, referred to as "superstrate". In the literature, the gain enhancement effect of the superstrate on different antennas including microstrip patch antennas has been confirmed. But using a superstrate on an EBG-backed microstrip patch antenna can be considered as another novelty of this thesis project, which led to further gain enhancement.

Microstrip patch antenna is used extensively in wireless and mobile applications due to its low-profile and lightweight. However, this antenna is prone to low gain, limited bandwidth and increased cross polarization levels. Electromagnetic Bandgap (EBG) structures are able to enhance the performance of this type of antenna. In this work, the performance of the patch antenna when integrated with EBG structure is investigated. A preliminary simulation study on the performance of a microstrip patch antenna integrated with Electromagnetic Bandgap (EBG) structures, indicated improvement in the radiation characteristics. First, the EBG characterization effort is undertaken. The bandgap of complementary and non-complementary form of five geometries are analyzed using the transmission line method. The analysis through simulation and measurement, show that complementary form sees a significant shift in the bandgap to lower frequencies and offer wider bandgap when compared to non-complementary form. Subsequently, gain performance of a square patch antenna when it is enclosed by complementary forms of either circular or square EBG cells are investigated. It emerges that the use of complementary EBG cells results in a comparatively better gain performance. The study includes a consideration of the groundplane size and the number of rows surrounding the patch, as these could affect the gain performance. This is followed by experimental measurements to substantiate the simulation outcome. Finally, the gain performance of a wideband antenna when it is configured with an EBG structure which functions as a reflector, also known as Artificial Magnetic Conductor (AMC) is investigated and reported. Four variations of the AMC structure are investigated i.e. a square cell backed by square cells (with and without vias) and square cells backed by a PEC (with and without vias). The properties of gain, impedance bandwidth and power patterns are measured and reported over the wideband frequencies of 3-10GHz.

This book is a detailed account of electromagnetic band gap (EBG) theory, analysis and applications, ideal for researchers and engineers.

This book describes the process of designing and analysing the microstrip antenna using EBG Structures. Since microstrip antennas are one of the most popular antennas that are used for high performance applications. These antennas have various advantages but they suffer from the narrow bandwidth. In order to overcome the narrow bandwidth Electromagnetic Band Gap (EBG) Structures can be used.The process of designing of the Electromagnetic Band Gap structures and various types of microstrip antennas are given in detail.

This book comprehensively reviews ultra-wideband (UWB) and UWB multi-input multi-output (MIMO) antennas with band-notched characteristics, with a focus on interference cancellation functionality. The book is organized into seven chapters that cover single band, dual band, and multi band-notched UWB antennas, followed by band-notched characteristics in UWB (MIMO) antennas. Further, it explains the mechanism of reconfigurability and tunability in band-notched UWB antennas, including advanced applications of UWB systems. Overall, it covers different techniques of canceling the electromagnetic interference in UWB in a concise volume. Features Provides a comprehensive presentation of avoiding interference in UWB systems Reviews state of the art literature related to UWB antennas, filtennas, and various reconfigurable technologies Explains different techniques for producing band-notch characteristics in UWB systems Includes discussion on historical perspectives of UWB technology Consolidates different research activities carried out on the electromagnetic interference cancellation techniques in the UWB communication systems Band-Notch Characteristics in Ultra-Wideband Antennas is aimed at researchers and graduate students in electrical and antenna engineering. Taimoor Khan has been an Assistant Professor at the Department of Electronics and Communication Engineering, National Institute of Technology Silchar since 2014. In addition to this, Dr. Khan has also worked as a Visiting Assistant Professor at Asian Institute of Technology Bangkok, Thailand during September–December, 2016. His active research interests include Printed Microwave Circuits, Electromagnetic Bandgap Structures, Ultra-wideband Antennas, Dielectric Resonator Antennas, Ambient Microwave Energy Harvesting, and Artificial Intelligence Paradigms in Electromagnetics. Dr. Khan has successfully guided three Ph.D. theses, and is supervising six Ph.D. students. He has published over 75 research articles in well-indexed journals and in world-renowned conference proceedings. Currently, he is executing three funded research projects, including two international collaborative SPARC and VAJRA research projects. In September 2020, Dr. Khan has been awarded a prestigious national IETE-Prof SVC Aiya Memorial Award for the year 2020. Yahia M. M. Antar has been a Professor at the Department of Electrical and Computer Engineering, Royal Military College of Canada since 1990. He served as the Chair of CNC, URSI from 1999 to 2008, Commission B from 1993 to 1999, and has a cross appointment at Queen’s University in Kingston. He has authored and co-authored over 250 journal papers, several books and chapters in books, over 500 refereed conference papers, holds several patents, has chaired several national and international conferences, and has given plenary talks at many conferences. Dr. Antar is a fellow of the Engineering Institute of Canada, the Electromagnetic Academy, and an International Union of Radio Science (URSI). He was elected by the URSI to the Board as the Vice President in 2008 and in 2014, and to the IEEE AP AdCom in 2009. In 2011, he was appointed as a member of the Canadian Defence Advisory Board (DAB) of the Canadian Department of National Defence. He serves as an Associate Editor for many IEEE and IET Journals, and as an IEEE-APS Distinguished Lecturer. Presently, he is working as President-Elect for IEEE Antenna and Propagation Society for the year 2020.

The use of dielectric resonator as a resonant antenna was proposed in 1983. Due to the absence of metallic loss, the dielectric resonator antenna (DRA) is highly efficient when operated at millimetre wave frequencies. With the use of high dielectric constant material, the DRA can also be used as a small and low profile antenna operated at low microwave frequencies. Low cost dielectric materials are now easily available commercially, encouraging more antenna engineers to design communication systems with DRAs.

This book is a reference for researchers who want to learn about resonant periodic structures for applications in microstrip circuits. The readers can learn simple methods to analyze these structures using commercially available software and equivalent circuit modelling. The application examples demonstrated in the book will open up new research ideas in this field.

The progress in modern tiny multifunctional wireless devices has dramatically increased the demand for microstrip antennas in recent years. Furthermore, in the last few years, such microstrip antennas found numerous applications in both the military and the commercial sectors. Therefore, microstrip patch antenna has become a major focus to the researchers in the field of antenna engineering. In this book, some recent advances in microstrip antennas are presented. This book contains mainly three sections. In the first section, some new approaches to modern analytical techniques rather than the conventional cavity model, transmission line model, or spectral domain analysis have been discussed. In the second section of the book, a light has been showered on some new techniques for bandwidth enhancement of microstrip radiators. In the last section of the book, the recent trends in microstrip antenna research have been showcased. Some newfangled application-oriented approach to this field is vividly discussed. The books main objective is to facilitate the microstrip antenna researchers for exploring the subject in more vibrant manner and also to revolutionize wireless communications. A sufficient number of topics have been covered, some for the first time in a research handbook. I hope that the book will surely be beneficial for scientists, practicing engineers, and researchers working in the field of microstrip antennas.

This useful tool provides the reader with a current overview of where microstrip patch antenna technology is at, and useful information on how to design this form of radiator for their given application and scenario. Practical design cases are provided for each goal.