Search

A tensor impedance surface waveguide is built using anisotropic unit cells. The waveguide can propagate a confined waveguide mode along its axis while waves incident to the guide at an orthogonal direction pass through as if the waveguides were not present. Both straight and curved implementations are demonstrated. Surface waves incident at an angle to the waveguide show reflection and refraction at the impedance interface. A theoretical model for tensor impedance surface waveguides is generalized to include dispersive unit cells and bending loss around curves. Dispersion results for modes propagating in the waveguide show agreement between the theory, simulation, and experimental measurements. A curved waveguide is also constructed which guides surface waves around a curve and is transparent to surface waves incident at an orthogonal angle.

We present an equivalent X-shaped lumped circuit network to be interposed in the transmission line (TL) modelling reflection and transmission through a recently proposed metalayer in planar technology. The metalayer consists of arrayed pairs of planar conductors that support two main resonant modes, corresponding to either a symmetric or an antisymmetric current distribution in the pairs. The antisymmetric mode is associated with artificial magnetism. We show that reflection and transmission features of a metalayer are accurately predicted by this simple but effective TL model. We also make a clear distinction for the first time between transmission peaks and resonance frequencies, and their relations are investigated in detail. This paper clearly defines the concept of magnetic resonance and identifies the analytical conditions corresponding to total reflection and transmission through a metalayer made of pairs of conductors supporting symmetric and antisymmetric modes. © 2012 IEEE.

A comparison of methods for calculating the field from a single dipole source in the proximity of an infinite periodic artificial material (PAM) is given. A direct plane-wave expansion method (PWM) is compared with the "array scanning method"(ASM). The ASM is shown to be the most efficient method for sources that are close to the PAM, since it only requires integration in the wavenumber plane over the Brillouin zone rather than over the entire wavenumber plane. It is also shown how the ASM may be used to efficiently calculate the Fourier transform of the field at any aperture plane, which is useful for asymptotic analysis. The ASM is shown to be more efficient than the PWM or the reciprocity method for calculating the transform of the aperture field. A discussion of the nature of the singularities in the complex wavenumber plane is given, and numerical issues associated with the implementation of the ASM are discussed. © 2007 IEEE.

A novel technique is proposed to calculate the field due to an arbitrary impressed source of finite extent in proximity with an infinite periodic structure such as an artificial material. The algorithm is based on a spectral domain finite-difference time-domain (FDTD) method combined with the array scanning method (ASM). Using this approach, only a single periodic cell of the periodic structure needs to be numerically modeled. Examples are used to demonstrate the accuracy and efficiency of the proposed approach. © 2007 IEEE.

A novel technique is proposed to calculate the field due to an arbitrary impressed source of finite extent in proximity with an infinite periodic structure such as an artificial material. The algorithm is based on a spectral domain finite-difference time-domain (FDTD) method combined with the array scanning method (ASM). Using this approach, only a single periodic cell of the periodic structure needs to be numerically modeled. Examples are used to demonstrate the accuracy and efficiency of the proposed approach. © 2007 IEEE.