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<div><div><div><p>This paper presents a uniform ray description of electromagnetic wave scattering by locally periodic metasurfaces of polygonal shape. The model is derived by asymptotically evaluating the critical-point contributions of a physical optics scattering integral. It is valid for metasurfaces whose bulk scattering coefficients are periodic functions of a phase parameter which, in turn, is a continuous and smooth function of surface coordinates. The scattered field is expressed in terms of reflected, transmitted and diffracted rays that do not generally obey conventional geometrical constraints (i.e., Snell’s law and the Keller cone). An iterative technique is presented to determine the locations of critical points on one or multiple interacting metasurfaces. Numerical results demonstrating the utility and accuracy of the asymptotic physical optics model are also provided.</p></div></div></div>

A high-resolution measurement system for the characterization of the delay and angle-of-arrival properties of all significant multipath components on mobile radio channels is presented. The system uses complex impulse response data obtained from a novel 3-D tilted cross switched antenna array as input to an improved version of 3-D Unitary ESPRIT. Results from simulations and measurements show that the approach is capable of accurately characterizing the delay and angle-of-arrival characteristics of the dominant multipath components at moderate urban speeds along a trajectory in mobile propagation environments with high resolution in both azimuth and elevation.

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