Attenuation of waves behind a building

A physical-optics (PO) solution is proposed for the diffraction of waves around a model building. The model building is constructed of two rectangular diffracting screens with reflecting surfaces joining the edges of the two screens. The solution can be expressed in terms of the well known attenuation function for two infinitely wide diffracting screens, applied several times. A comparison is made with previous work on the same subject, and it is found that the PO solution agrees with a simpler PO solution if paraxial theory is used, but it agrees with a uniform version of the geometrical theory of diffraction solution if a wide-angle correction is applied. A contour plot of field amplitude at a constant height reveals an interference pattern between the wave arriving over the roof and the wave arriving around the walls.