Artificial materials have been widely studied and used in photonics and microwaves in the last few decades. Recent research has proven that the introduction of specific higher symmetries in each cell of a periodic medium is an effective approach to obtain unprecedented exotic behaviors and to overcome the current limitations of these devices. For example, simple symmetries of a purely spatial type (glide or twist transformations) can have a huge impact on the properties of the resulting materials, thus defining wideband behaviors for flat lenses or large stop bands for novel EBG materials. This Special Issue opens with a novel discussion on the effect of time-reversal symmetries in antenna theory and presents new structures exploiting symmetries for antenna and microwave components, such as flat lenses, helix antennas, and gap-waveguides. Finally, new modeling methods are discussed for the study of wave propagation along glide surfaces and twist lines.

Artificial materials have been widely studied and used in photonics and microwaves in the last few decades. Recent research has proven that the introduction of specific higher symmetries in each cell of a periodic medium is an effective approach to obtain unprecedented exotic behaviors and to overcome the current limitations of these devices. For example, simple symmetries of a purely spatial type (glide or twist transformations) can have a huge impact on the properties of the resulting materials, thus defining wideband behaviors for flat lenses or large stop bands for novel EBG materials. This Special Issue opens with a novel discussion on the effect of time-reversal symmetries in antenna theory and presents new structures exploiting symmetries for antenna and microwave components, such as flat lenses, helix antennas, and gap-waveguides. Finally, new modeling methods are discussed for the study of wave propagation along glide surfaces and twist lines.

This book describes innovative design solutions for radio-frequency identification (RFID) tags and antennas. Focusing mainly on passive ultra-high-frequency (UHF)-RFID tag antennas, it examines novel approaches based on the use of metamaterial-inspired resonators and other resonant structures as radiating elements. It also offers an exhaustive analysis of the radiation properties of several metamaterial-inspired resonators such as the split ring resonator (SRR) and related structures. Further, it discusses in detail an innovative technology for the RFID tagging of optical discs, which has demonstrated a significant improvement over the state of the art and resulted in a patent. By covering the entire research cycle of theory, design/simulation and fabrication/evaluation of RFID tags and antennas, while also reporting on cutting-edge technologies, the book provides graduate students, researchers and practitioners alike with a comprehensive and timely overview of RFID systems, and a closer look at several radiating structures.

Metamaterials and metasurfaces are enabling modern 5G/6G wireless systems to achieve high performance while maintaining efficient costs and sizes. In the wireless industry, transmission lines play a fundamental role in the development of guided wave elements, antennas, radio frequency identification (RFID) tags, and sensors whose efficiency may be enhanced using metamaterials. Additionally, a metamaterial absorber can solve the bandwidth issue of the internet of things (IoTs) backhaul network. Metasurfaces are also potential candidates for implementing reconfigurable intelligent surfaces (RISs) due to their special wireless communication capabilities. Metamaterial Technology and Intelligent Metasurfaces for Wireless Communication Systems compiles and promotes metamaterials research and sheds light on how metamaterials and metasurfaces will be used in the 5G era and beyond. Covering topics such as active and passive metamaterials, metasurfaces-inspired antennas, and metamaterials for RFID and sensors, this book is ideal for researchers, students, academicians, and professionals.

In the ever-evolving landscape of electromagnetic wave control, researchers face the pressing challenge of keeping pace with the rapid advancements in metasurface and metamaterial methods. As these technologies become increasingly integral to various engineering applications, educators and researchers seek a comprehensive resource that outlines the current state of the field and offers insights into its future prospects. Electromagnetic Wave Control Techniques of Metasurfaces and Metamaterials emerges as a timely solution, providing a detailed overview and a forward-looking perspective on wave control research using metasurfaces and metamaterials. With a firm focus on bridging the gap between theory and application, this book meets the critical need for a comprehensive understanding of key topics such as frequency selective surfaces, metasurface and metamaterial absorbers, reflectors, and the integration of deep learning and machine learning in these domains. This book equips readers with the knowledge and tools necessary to tackle real-world challenges in wavefront control, beam steering, and phase control by delving into the intricacies of broadband metasurfaces, metamaterials, and the underlying physics. Furthermore, it explores the unique capabilities of chiral metasurfaces and metamaterials, illuminating their diverse engineering applications and empowering the readers with practical insights.

This book presents and discusses strategies for the design and implementation of common-mode suppressed balanced microwave filters, including, narrowband, wideband, and ultra-wideband filters This book examines differential-mode, or balanced, microwave filters by discussing several implementations of practical realizations of these passive components. Topics covered include selective mode suppression, designs based on distributed and semi-lumped approaches, multilayer technologies, defect ground structures, coupled resonators, metamaterials, interference techniques, and substrate integrated waveguides, among others. Divided into five parts, Balanced Microwave Filters begins with an introduction that presents the fundamentals of balanced lines, circuits, and networks. Part 2 covers balanced transmission lines with common-mode noise suppression, including several types of common-mode filters and the application of such filters to enhance common-mode suppression in balanced bandpass filters. Next, Part 3 examines wideband and ultra-wideband (UWB) balanced bandpass filters with intrinsic common-mode suppression. Narrowband and dual-band balanced bandpass filters with intrinsic common-mode suppression are discussed in Part 4. Finally, Part 5 covers other balanced circuits, such as balanced power dividers and combiners, and differential-mode equalizers with common-mode filtering. In addition, the book: Explores a research topic of increasing interest due to the growing demand of balanced transmission lines and circuits in modern communication systems Includes contributions from prominent worldwide experts in the field Provides readers with the necessary knowledge to analyze and synthesize balanced filters and circuits Balanced Microwave Filters is an important text for R&D engineers, professionals, and specialists working on the topic of microwave filters. Post graduate students and Masters students in the field of microwave engineering and wireless communications, especially those involved in courses related to microwave filters, and balanced filters and circuits will also find it to be a vital resource.