It should be noted here

It should be noted here that for the seif tem, (kp) can Vary from zero to O. 1 s (if segment width is 0.1 I ). As expecbd, convergence of this tenn is mch better than equation (2.25). a) Plotting of the radiation pattem of this scattering problem was done using the moment method solution based on equations (2.24). (2.25) end (2.26). Equaüon (2.26) was cornputeci using numerical integration. Figure 2.6 shows radiation patterns for a segment wigdth of 0.1 L A wmparisori made with resub computed by TECYL and al- GTD showsd that only at a segment width of le= than 0.005 1 that the radiation pattern begins to be accurate. b) The sam ptoMem was sdved by the moment methocl with the fdlom'ng differenœ: TDRS equation (2.25) was replaced by the exact formula of equation (2.26) and it was integrated nurnerically. Figures 2.7 shows the radiation patterns for a segment width of O. 1 L The plot is identical to plots obtained by TECYL and GTD. lt is obvious that the method used in b) with segment Wdth =0.11 (50 segments) achieved the same result as meaiod in a) with segment width = 0.001L (5000segments). Hence, it is sak to say that the approximations in P] for &,, are bad, and that the integral shwld be done numerically or a more accurate closed fom used. Great are must be taken when computing impedanœ tem in moment method solutions for scattering problems. Not only the self term must be fomnilsted accurately but also muhial impedanœ W m accuracy foi adjacent segments must be taken into account to obtain acceptable rwub using typical segment width of 0.n to 0.2 A.

It should be noteâ that the penalty paid (becau- of loop coniputing adjacent terni impedanœs) is normally lees thon the pnaîty paid because of the inctease in the simultaneous linear equations nurnber (due to fine slicing of segments). It was decided after this investigation that pulse basis fundions and point matching were adequate enough for the customizd moment method codes to be created thmughout this work