Preface

As the demand for reliable, high-speed wireless communication systems satisfying demanding Quality-of-Service (QoS) constantly increases, the antenna systems research community strives to keep up with the growing demand by introducing emerging stateof-art designs and techniques for various applications such as 5G, MIMO and massive MIMO, vehicular communications, implantable medical systems, radar, navigation and more. This book aims to present recent advances in modern designs and techniques used in the development of antenna systems written by experts in the field. The book consists of thirteen chapters. It is ideal for researchers, engineers, senior undergraduate students and graduate students working in the field of antenna systems design.

Chapter one demonstrates multiple comparisons between Stochastic Channel Modeling (SCM) tools and Ray Tracing (RT) tools for contemporary vehicular wireless systems. The comparisons take place in indoor and outdoor environments using a 2 by 2 antenna system to evaluate the Multiple-Input Multiple Output (MIMO) channel capacity for each channel modeling technique. Additionally, the chapter evaluates the performance of these modeling techniques for a vehicle to everything (V2X) and 5G applications using state-of-the-art commercial RT and SCM tools.

Chapter two presents the performance analysis of MIMO systems under different channel conditions determined by the channel state information with a novel adaptive power allocation algorithm implemented to improve the spectral efficiency for 4G and 5G applications. The chapter provides the algorithm development process along with detailed analysis of its performance.

In chapter three, the authors present steered beam antenna arrays and evaluate their performance using a signal processing algorithm to adaptively control and steer the main lobe of the antenna array.

Chapter four proposes a 4-element linear antenna array block with a transistor amplifier operating at 28 GHz 5G frequency band. The antenna elements are patch-shaped printed on Rogers-Duriod 5880 substrate with thickness is 0.127mm. This co-design block is intended to tackle the issues of radio coverage and the requirements of high-speed data transfer for 5G.

Chapter five of this book presents an optimized NxN bi-ellipse microstrip antenna array with a thin cross-section and lightweight mass that operates in multiband frequency for satellite communications. The chapter provides the design process of the proposed antenna array and verifies the simulation results against measurements of the fabricated antenna.

Chapter six provides an explicit comparison between different kinds of linear sparse antenna arrays in terms of the aperture provided for a given number of sensors, ability to provide hole-free co-arrays, degrees of freedom, susceptibility to mutual coupling, and angular resolution.

Chapter seven focuses on the importance of implantable wireless systems for medical applications. Several challenges arise while designing implantable devices, one of the main challenges is energy consumption. While these devices can harvest electromagnetic energy, it is still insufficient when it is intended to generate and analyze/process more data. This chapter also provides a review of the latest wireless power transfer techniques that can be used to overcome these challenges.

Chapter eight provides a general overview of the design requirements, steps and testing of microwave antennas used for various biomedical applications such as pacemakers, implantable defibrillators, monitoring human body temperature, continuous glucose monitoring, heart failure detection, and many more. It identifies the different research areas of antennas in the biomedical field with the antenna specifications for each application while stating the opportunities and challenges of each antenna design.

The general concept of metalens based antenna technology is discussed in chapter nine for different application under microwave frequency and up to terahertz and optical frequencies. The chapter also presents recent design developments in metalens antennas and their various applications.

Chapter ten introduces a review on blue laser diode-based Visible Light Communication (VLC) and Solid-State Lighting (SSL). As the demand for ultra-high-speed wireless data communication is rapidly growing, VLC using Gallium nitride phosphor-converted white light-emitting diodes (Pc-WLEDs) is one of the most emerging techniques for high-speed VLC and SSL, as the chapter reveals.

In chapter eleven, a near-field propagation analysis is proposed using simulated near-field data with corresponding meshed structure data in the time domain to provide a better understanding of the Electromagnetic (EM) propagation process on travelling-wave antennas. The chapter additionally presents a particular space-time-frequency analysis where the EM energy transfer out of the antenna is evaluated.

Chapter twelve provides a detailed overview of the principles of wireless power transfer techniques which have attracted significant recent research interest. The receiver block is discussed in-depth with emphasis on the features of rectifier technologies. Finally, the chapter continues to describe rectenna systems adopted in charging sensors in the realm of the Internet of Things (IoT) in remote locations.

The authors would like to gratefully acknowledge Dr. Lawrence Whitman, Dean of the Donaghey College of Science, Technology, Engineering, and Mathematics, University of Arkansas Little Rock for the encouragement he offered throughout this project. Thanks are due to Mrs. Karmen Đaleta and Mr. Darko Hrvojić, Author Service Managers, INTECHOPEN LIMITED for the expert assistance offered.
