1,721,086 research outputs found
Diffraction coefficients at edges in artificially soft and hard surfaces
No full textIn this Letter, both uniform GTD and incremental diffraction coefficients at edge discontinuities in artificially soft and hard surfaces are obtained from the exact solution of the relevant canonical wedge configuration. Numerical results are presented for a dipole on the axis of an artificially soft disk
Diffraction at a plane angular sector
No full textA closed form solution is presented for the scattering in the far zone by a vertex at the interconnection between the two edges of a plane angular sector, when it is illuminated by a plane wave. The solution is obtained as a superposition of simple interaction mechanisms between the two adjacent edges. The spectral representation of the field diffracted by the first edge is used to illuminate the second edge. The response of the latter is evaluated by applying the induction principle at the plane angular sector. In spite of the simplicity of this basic assumption, the resulting expressions recover in the pertinent directions the dominant edge ray field contributions, including second order diffraction mechanisms. The solution is cast in a very simple, compact matrix form, which explicitly satisfies reciprocity
A hybrid technique for caculating the field of wire antennas near an interface
No full textNot availabl
A uniform GTD formulation for the diffraction at a wedge with two face impedances
No full textNot availabl
An incremental theory of double edge diffraction
No full textA novel general procedure for defining incremental field contributions for double diffraction at a pair of perfectly conducting (PEC) wedges in an arbitrary configuration is presented. The new formulation provides an accurate first-order asymptotic description of the interaction between two edges, which is valid both for skewed separate wedges and for edges joined by a common PEC face. It also includes a double incremental slope diffraction augmentation, which provides the correct dominant high-frequency incremental contribution at grazing aspect of incidence and observation. This new formulation is obtained by applying to both edges, the wedge-shaped incremental dyadic diffraction coefficients for single edge diffraction. The total doubly diffracted field is obtained from a double spatial integration along each of the two edges on which consecutive diffractions occur. It is found that this distributed field representation precisely recovers the doubly diffracted field predicted by the uniform theory of diffraction (UTD) and that may be applied to complement ray field methods close to and at caustics. It can be applied as well in all those situations in which a stationary phase condition is not yet well established. Numerical examples are presented and compared with those calculated from both Method of Moment solution and second-order UTD ray techniques. Excellent agreement was found in all cases examined
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