Electromagnetically metamorphic interfaces, objects and materials: An artificially intelligent substrate

For general artificial multilayered structures (Photonic Band Gap (PBG) or Electromagnetic Band Gap (EBG) metamaterials) with centrosymmetric scattering matrices, the composite may be replaced by an equivalent homogeneous dispersive magneto-dielectric material and may be used for the design of integrated circuits, filters and antennas using standard methods. Otherwise, use of the scattering matrix approach to obtain the effective parameters is valid only for semi-infinite structures.;We present a novel semi-analytical methodology to analyze a periodic array of printed metallic closed ring elements in a multilayered dielectric structure. This approach is unique in that it is the first methodology capable in modelling structures with resonant implants and inter-element dimensions well beyond the Effective Medium Theory (EMT). In addition, it yields computational efficiency by two orders of magnitude over standard computational methods in computing the scattering parameters for a perfect electric conductor (PEC) closed ring multilayered periodic (EBG, PBG) structures. Moreover, it provides physical insight in the implementation of metallic implants for practical applications. This methodology satisfies the Kramers-Kronig relations and Causality and therefore allows for the development of semi-analytical expressions for the composite's wave impedance, index of refraction, as well as the permittivity and permeability parameters accounting for full dispersion. The upper band edge is determined by the host material uniquely, and the bandwidth is determined by the shunt susceptance for different PEC ring inclusions.;Electromagnetic metamorphism is defined in this study as the complete transformation of a scattering object of fixed shape and dimensions from one electromagnetic state to another (e.g. from a perfect electric conductor (PEC) to a perfect magnetic conductor (PMC)). Every scatterer may undergo five distinct metamorphic states, which are Perfect Electric Conductor, Perfect Absorber, Perfect Passive Magnetic Conductor, Perfect Active Magnetic Conductor and Perfect Amplifier. Furthermore, all scatterers with characteristic dimensions large compared to wavelength exhibit the same universal metamorphic response in the backscattering direction. The five metamorphic states are determined initially in terms of the backscattering properties of objects characterized by a continuously varying surface impedance. Subsequently, a PBG structure is considered with implant elements with variable electrical properties. The impact of metamorphism on the composite's effective parameters is studied and specific data are shown.;We also demonstrate that a metamaterial constructed by layered actively loaded array of PEC circular rings shows a negative index of refraction. The composite's effective parameters ne (index of refraction) and ze (wave impedance) are examined. Loss in the dielectric host plays an important role in the effective parameters of the composite material. The effective index of refraction exhibits a distinct behavior between the composites with a lossless and a lossy dielectric host, even if the loss is very small.;Finally, we demonstrate that size reduction of a electromagnetically metamorphic material can be realized by utilizing the spiral implants. A thin X-band microwave absorber has been designed and fabricated based on the spiral medium. Both the simulation and measurement results agree well.