A numerical approach to the solution of radio diffraction problems

It is proposed t ha t so me diffraction problems can be conve nie n tl~r solved by a d irect numerical in tegrat ion of t he Fresnel-Kirchhoff formu la. T Il(' required properties of t he diffrac t ion screen are represe nted by a series of numbers which ca n be eithe r regula r and periodic, or partially random. The necessa ry limits and in teg ratio n inte rvals are co ns idered. and the method is found t o be con venien t for Fresnel diffraction a nd fo r ir regulari t ies not too large compared t o the wavelength . Both deep a nd shallow modulation can be t reated. The acc Llracy of t he computat ions is verified in a simple case of sin usoida l mod ulat ion, and some new results a re deri ved for rando m p hase screens.