| Electromagnetic Negative Index Metamaterials (NIM) exhibit many novel phenomena such as negative Snell's law, backward wave propagation, reverse Cerenkov radiation, and reverse Doppler effect. Predicted theoretically by Veselago in 1968 and experimentally demonstrated and verified barely a decade ago, it has enabled many proof-of-concept applications not achievable with ordinary materials. However, from a practical perspective, synthesis issues such as material designs and fabrication techniques need to be improved for NIM to be useful.;The goal of this work is to investigate and realize the practical potentials of NIM. To achieve this goal, the physical properties of NIM and their implications are reviewed to establish a fundamental theoretical understanding and appreciation. Experimentally, the constituent unit cells that make possible the realization of NIM are described. Unit cell simulation, fabrication, testing, and material properties extraction techniques and tools are developed to form the basic building blocks.;In addition to being able to achieve negative index of refractions, NIM can be used to realize a continuum of material values with independent control of elect is permittivity and magnetic permeability. This newly found capability enables the development of the related field of transformation optics. An electromagnetic cloaking device, one of the first major proof-of-concept devices only made possible by the advent of NIM and transformation optics is simulated to demonstrate NIM's versatility.;A major effort of this work is the design, fabrication, and testing of a NIM lens to scan phased-array antenna beams to the horizon. Lens design and optimization tools are developed, and the transformation optics technique of conformal mapping is used to transform the lens from a curved geometry to a faceted buckyball shell for easier fabrication.;Other NIM applications also investigated are coated dielectric spheres for isotropic NIM unit cells, flat gradient index lenses, waveguide bandpass and bandstop filters, and a microstrip line bandstop filter. Finally, inspired by electromagnetic NIM, acoustic NIM has became a hot research topic in the last couple of years. The fundamentals of acoustic NIM and material synthesis are briefly reviewed. Potential applications in acoustic cloaking, noise cancellation and vibration damping are presented. |
