Scattered microwave energy and building surface features

It has been shown previously by the authors (Electron. Lett., vol.23, no.18, p.922-4, 1987) that city structures with regular layouts of streets and buildings present an ordered geometry whose effect on scattered interference, although heretofore neglected, is significant. A method is developed to characterize the effect of such building features. Scattering patterns from building structures are described in terms of a functionality equivalent facade made of finite number of smooth panels with small random tilts about its plane. The scattering problem is defined by the orientation of the buildings, and the gross structure of building surfaces is characterized by the number of panels with distinct offset from each other azimuthal tilt and attenuation by the material of the building facade. The reasonable bounds for the first two parameters are 1<N⩽10; 0<S_τ⩽1°. Within these bounds, for a facade of given surface area the level of off-specular interference increases nearly linearly with the number of panel subdivisions. The degree of tilt determines the broadening of the beam pattern in the near specular direction. The amount of interference in the nonspecular region is estimated using both the physical and geometrical theories of diffraction. The observed interference in Kansas City is within bounds predicted by the building model