frequency can be used, with diffraction still being considerd as a local phenornenon. Figures 3.9, 3- 1 1, 3.13 and 3.15 depict the airrent density on strips of width 1 .A, OSÂ, 0.2A and 0.1A respecüvely. Multiple diffraction was taken into account for current camputation. Figures 3.10, 3.1 2. 3.14 and 3.16 depict the current density on stnps of width 1 .IL. 0.5Â, 0.211 and 0.1k respectively. Only simple dimadion was considerad for cumnt computation. It is obvious that when multiple diffraction is nd taken into account, relatively big enors begin to be introduœâ at eâges for rlic to end up with a totally ditfsrent cunent distribution at w=O.lL. When multiple diffraction is taken into account, UTD results are almost identical ta moment mathod results. More surprising is that the UTD works quite well dom to 0.111. b) m er amles of incidence: Figures 3. l?, 3.18 and 3.1 9 depict the cunent distribution on a strip of wïdth ~0.211 illuminateci by a plane wave at 60'. 10' and 0.5' (near grazing) angle of incidence respectively . Figures 3.20, 3.21 and 3.22 show the current distribution on a strip of width w=0.11 illuminateci by a plane wave incident a 60°, 10' and 0.5' respedively . Both sets of figures take into account multiple diffractions in computing cunent densities. They show cleariy that msuL süll compare wdl. wiai the dhmnce behmren the UT0 and moment mahod resulb, inmasing at near grazing angles for smaller strip width. The maximum diffemnœ ddectd behnmn the values of both mahods (as a prœntage of th momnt matid val-) is süll howuver less than 5%.
Fig 3.9: Magnitude of cwrent density on both swfaces of a strip of width IF 1 1 illuminatecl by a TEz plane wave incident at q'=9O0 (J in Alm p in i.). [- Multiple diffraction UTD solution ooo MM nith 500 segrnenis]