Average field attenuation in the nonregular impedance street waveguide

The propagation of electromagnetic (EM) waves in a city with a regularly planned building as a model of a straight street with buildings lining its sides is investigated. The street is considered as a planar two-dimensional (2-D) multislit waveguide with Poisson distributed screens (building walls) and slits (gaps between buildings). The electrical properties of the buildings´ walls are taken into account by introducing the electrical impedance as a function of their surface permittivity and conductivity. The average field from the vertical electric dipole placed inside the street lower than rooftop level in the conditions of line-of-sight is investigated using Green´s function formalism and real boundary conditions on the building walls. Evaluations show that the total field inside the waveguide can be presented as a superposition of a continuous spectral propagation component, which does not exist in the ideal unbroken waveguide, and a discrete spectral component, which describes the exponential attenuation of reflected and diffracted waves at distances of up to 23 km depending on the width of street. The presented model and evaluated formulas are in a good agreement with experimental data of ultrahigh-frequency (UHF)/L-band wave propagation in urban areas with a crossing-street plan