A NEW APPROXIMATE FORMULA FOR SITE SHIELDING BY A KNIFE-EDGE OBSTACLE, BASED ON MEASUREMENTS FROM 8 TO 94 GHZ

This article proposes a new approximate formula for determining the ef fectiveness of site shielding by a knife-edge obstacle, by adding a co rrection term to the ITU-R formula. The new formula is accurate to wit hin 0.1 dB for diffraction angles less than 12 degrees if the distance from obstacle to antenna is larger than 100 wavelengths, and to bette r than, respectively 0.5 and 1 dB for diffraction angles less than 35 degrees and 45 degrees, as compared with, respectively, 3 and 5 dB obt ained by the ITU-R formula. It is based on UTD, after an experimental validation from 8 to 94 GHz. (C) 1995 John Wiley and Sons, Inc.