Showing papers on "Metamaterial published in 1999"

Surface electromagnetic waves in two-dimensional photonic crystals: Effect of the position of the surface plane

Abstract: A semi-infinite photonic crystal can support electromagnetic wave propagation at its surface By using the supercell method, we studied in detail the properties of these (nonradiative) modes in crystals of two-dimensional periodicity constituted by parallel rods of square cross section The rods cut the plane of periodicity (001) at the sites of a square lattice, and the sides of the rods have the same orientation as the lattice We have performed calculations for crystals of air cylinders in a dielectric background The Bloch-type surface waves are assumed to propagate at the (100) surface in the [010] direction For both transverse electric and transverse magnetic polarizations, we found that the dispersion curves of the surface modes and their field confinements at the surface are strongly dependent on the crystal termination, that is, on the position of the cut plane through the rods We also found that the degree of localization of the fields at the surface depends on the position of the mode within the band gap Plots of the field intensity show that the TM waves are more strongly localized than the TE waves

Parallel-plate mode reduction in conductor-backed slots using electromagnetic bandgap substrates

Abstract: By fabricating a resonant slot over a reflecting back plate and filling the resulting parallel-plate with an appropriately designed artificial electromagnetic bandgap (EBG) structure, noticeable enhancements in both radiation pattern and bandwidth are achieved using a significantly lower profile than traditional designs. This design uses a two-dimensional artificial EBG substrate in conjunction with a reflecting plate to completely block radiation from the backside of the slot from propagating to the finite edges of the resulting parallel-plate cavity. Measured and simulated data for conductor-backed slots with homogeneous substrates and with EBG substrates are compared.

Roles of wave impedance and refractive index in photonic crystals with magnetic and dielectric properties

Abstract: We investigated the roles of wave impedance and refractive index in photonic crystals by means of analytical expressions for edges frequencies of a photonic bandgap (PBG) in a one-dimensional photonic crystal with magnetic and dielectric properties. The analytical expressions were derived when the optical thicknesses of layers are the same. The wave impedance governs the formation of PBG's and the intensity of defect modes. Meanwhile, the position of PBG's and the creation of defect modes are related to the refractive index.

Plasmon model for origin of earthquake related electromagnetic wave noises

Abstract: A theory is proposed to explain how the electromagnetic waves are created from the epicenter of large earthquakes. By the increase of strong stress in the rock, exo-electrons are excited and emitted, and bulk plasmon can be produced. They propagate to the earth surface, and transform into electromagnetic waves. Simple order-estimation shows that the electromagnetic waves of the frequency range 10MHz-1 GHz may be observed. Some characteristics of observed earthquake related electromagnetic waves may be interpreted by our plasmon model.

Photonic crystals: slow-wave structures for optical range

Abstract: Some peculiarities of the electromagnetic waves propagation in photonic band gap structures are considered. The wave phenomena at the edge of band gaps of 1D structures stimulating the nonlinear processes are described. Some examples of unusual optics laws in 2D structures are given.