A novel microstrip patch antenna topology is presented for achieving a dual-band response with arbitrarily closely spaced resonances. This topology is based on a coupled transmission line structure in order to take advantage of the separation in propagation constants for parallel (even-mode) and anti-parallel (odd-mode) current modes. Applying a metamaterials inspired design approach, periodic reactive loadings are used to design the underlying transmission line to have specific propagation constants necessary to realize a desired separation between two resonant frequencies. Using a single probe feed for a finite coupled line segment, both even-and odd-mode resonances can be excited to radiate efficiently at their respective design frequencies. The efficiency of the odd-mode radiation is enhanced by separating the two lines, while strong coupling is maintained by inserting a series of narrowly-separated thin loops between them. Several example resonant antenna designs, in the 2.45 GHz band, are presented. The directivities of these microstrip patch antennas are enhanced by optimizing the physical length of the resonant structure. For a resonant antenna obtained by cascading several unit cells of reactively loaded microstrip segments, dispersion analysis is employed for the unit-cell design. Maximum directivity is achieved by choosing the overall physical length to be slightly less than a half wavelength in free space at the design frequency. This gain optimization is applied to three coupled-line antennas, as well as a single resonance patch. Excellent agreement is observed between simulated and measured responses across all designs. The potential of loading the coupled line structure with active components is also explored. Varactor diodes are placed on coupled-line structures in two configurations. In one configuration, both resonant frequencies are affected. In the other configuration, only the odd-mode characteristics are reconfigured. In this way, the resonant frequency of either one or both modes can be adjusted by applying a DC bias voltage to the varactor diode loading elements. Two antennas, one employing each of these topologies, were designed and fabricated. Control of the resonant frequency over the predicted range through applying a bias voltage is observed with the fabricated prototypes.

Electromagnetic metamaterials-from fundamental physics to advanced engineering applications This book presents an original generalized transmission line approach associated with non-resonant structures that exhibit larger bandwidths, lower loss, and higher design flexibility. It is based on the novel concept of composite right/left-handed (CRLH) transmission line metamaterials (MMs), which has led to the development of novel guided-wave, radiated-wave, and refracted-wave devices and structures. The authors introduced this powerful new concept and are therefore able to offer readers deep insight into the fundamental physics needed to fully grasp the technology. Moreover, they provide a host of practical engineering applications. The book begins with an introductory chapter that places resonant type and transmission line metamaterials in historical perspective. The next six chapters give readers a solid foundation in the fundamentals and practical applications: Fundamentals of LH MMs describes the fundamental physics and exotic properties of left-handed metamaterials TL Theory of MMs establishes the foundations of CRLH structures in three progressive steps: ideal transmission line, LC network, and real distributed structure Two-Dimensional MMs develops both a transmission matrix method and a transmission line method to address the problem of finite-size 2D metamaterials excited by arbitrary sources Guided-Wave Applications and Radiated-Wave Applications present a number of groundbreaking applications developed by the authors The Future of MMs sets forth an expert view on future challenges and prospects This engineering approach to metamaterials paves the way for a new generation of microwave and photonic devices and structures. It is recommended for electrical engineers, as well as physicists and optical engineers, with an interest in practical negative refractive index structures and materials.

One goal of this thesis is to address several challenging compact antenna design issues by using transmission-line metamaterials. In particular, we demonstrate the design of a compact antenna with an extended bandwidth, multiband/multifunction compact/small antennas, and mutual-coupling reduction for two closely-spaced small antennas. The proposed compact transmission-line metamaterial antenna employs the concept of zeroth- index resonance and a wideband characteristic is enabled by detuning the resonance of each constituent metamaterial unit cell at a slightly different frequency, thus creating a multi-resonant return-loss passband. Furthermore, a single-cell transmission-line metamaterial loading scheme is applied to regular printed monopole antennas in order to introduce additional resonances at the low band and create multiband small antennas that meet the specifications for WiFi and WiMAX applications. Lastly, a simple approach for reducing the mutual coupling in two closely-spaced small antennas is also presented, based on the idea of self-cancelation of the induced currents.The other important goal of this thesis is to develop volumetric negative-refractive-index transmission-line (NRI-TL) metamaterials. A volumetric NRI-TL slab is created by stacking 2D NRI transmission-line grids in the shunt-node configuration. This is done in a simple manner through images induced in a parallel-plate environment. Additional vias are strategically placed to suppress the parasitic parallel-plate mode. Moreover, multiconductor transmission-line theory is used to model the volumetric metamaterial slab. A fully-printed volumetric Veselago-Pendry transmission-line lens is designed and matched to free space. Using this proposed lens, it has been experimentally verified that the diffraction limit can be overcome.

The book presents an engineering approach for the development of metamaterials and metasurfaces with emphasis on application in antennas. It offers an in-depth study, performance analysis and extensive characterization on different types of metamaterials and metasurfaces. Practical examples included in the book will help readers to enhance performance of antennas and also develop metamaterial-based absorbers for a variety of applications. Key Features Provides background for design and development of metamaterial structures using novel unit cells Gives in-depth performance study of miniaturization of microstrip antennas Discusses design and development of both transmission and reflection types, metasurfaces and their practical applications. Verifies a variety of Metamaterial structures and Metasurfaces experimentally The target audience of this book is postgraduate students and researchers involved in antenna designs. Researchers and engineers interested in enhancing the performance of the antennas using metamaterials will find this book extremely useful. The book will also serve as a good reference for developing artificial materials using metamaterials and their practical applications. Amit K. Singh is Assistant Professor in the Department of Electrical Engineering at the Indian Institute of Technology Jammu, India. He is a Member of the IEEE, USA. Mahesh P. Abegaonkar is Associate Professor at the Centre for Applied Research in Electronics at the Indian Institute of Technology Delhi. He is a Senior Member of the IEEE, USA. Shiban Kishen Koul is Emeritus Professor at the Centre for Applied Research in Electronics at the Indian Institute of Technology Delhi. He is a Life Fellow of the Institution of Electrical and Electronics Engineering (IEEE), USA, a Fellow of the Indian National Academy of Engineering (INAE), and a Fellow of the Institution of Electronics and Telecommunication Engineers (IETE).

This book uses the first volume’s exploration of theory, basic properties, and modeling topics to develop readers’ understanding of applications and devices that are based on artificial materials. It explores a wide range of applications in fields including electronics, telecommunications, sensing, medical instrumentation, and data storage. The text also includes a practical user’s guide and explores key areas in which artificial materials have developed. It includes experts’ perspectives on current and future applications of metamaterials, to present a well-rounded view on state-of-the-art technologies.

In-depth analysis of the theory, properties and description of the most potential technological applications of metamaterials for the realization of novel devices such as subwavelength lenses, invisibility cloaks, dipole and reflector antennas, high frequency telecommunications, new designs of bandpass filters, absorbers and concentrators of EM waves etc. In order to create a new devices it is necessary to know the main electrodynamical characteristics of metamaterial structures on the basis of which the device is supposed to be created. The electromagnetic wave scattering surfaces built with metamaterials are primarily based on the ability of metamaterials to control the surrounded electromagnetic fields by varying their permeability and permittivity characteristics. The book covers some solutions for microwave wavelength scales as well as exploitation of nanoscale EM wavelength such as visible specter using recent advances of nanotechnology, for instance in the field of nanowires, nanopolymers, carbon nanotubes and graphene. Metamaterial is suitable for scholars from extremely large scientific domain and therefore given to engineers, scientists, graduates and other interested professionals from photonics to nanoscience and from material science to antenna engineering as a comprehensive reference on this artificial materials of tomorrow.

This book presents and discusses alternatives to ordinary transmission lines for the design and implementation of advanced RF/microwave components in planar technology. This book is devoted to the analysis, study and applications of artificial transmission lines mostly implemented by means of a host line conveniently modified (e.g., with modulation of transverse dimensions, with etched patterns in the metallic layers, etc.) or with reactive loading, in order to achieve novel device functionalities, superior performance, and/or reduced size. The author begins with an introductory chapter dedicated to the fundamentals of planar transmission lines. Chapter 2 is focused on artificial transmission lines based on periodic structures (including non-uniform transmission lines and reactively-loaded lines), and provides a comprehensive analysis of the coupled mode theory. Chapters 3 and 4 are dedicated to artificial transmission lines inspired by metamaterials, or based on metamaterial concepts. These chapters include the main practical implementations of such lines and their circuit models, and a wide overview of their RF/microwave applications (including passive and active circuits and antennas). Chapter 5 focuses on reconfigurable devices based on tunable artificial lines, and on non-linear transmission lines. The chapter also introduces several materials and components to achieve tuning, including diode varactors, RF-MEMS, ferroelectrics, and liquid crystals. Finally, Chapter 6 covers other advanced transmission lines and wave guiding structures, such as electroinductive-/magnetoinductive-wave lines, common-mode suppressed balanced lines, lattice-network artificial lines, and substrate integrated waveguides. Artificial Transmission Lines for RF and Microwave Applications provides an in-depth analysis and discussion of artificial transmission lines, including design guidelines that can be useful to researchers, engineers and students.