so that 
Let D-~2, 
Ge 
R= [aw exp jur a] (cosa- cosdo )* + (cos8- cos8o )° cos(g-Go na 
D =r 
and if 
5) 
In the following, let #(g) = 
Z1 = 0, Ge = 2n 
exp jkr VN (cosa-cosds )* + (cos8- cos80}” cos(g-Go Mee (15a) 
aqTl 
O 
If 
Ba 2 OL ga. 
TI 
R= ij expjarv (cosa-cosdo )* + (cos8- cosBo )* costars) (150) 
Oo 
If 
fin ==> oe =m 
TT 
2 
Rs \ [espns (cosa- costo )* + (cos8-cosBo )* cos(Z-Go | racase 
TT 
a 
These integrals can be evaluated by the use of the formulas 
(see Appendix C): 
ei 
| cos (@-p0 dap = Orien2 Oa be (27) 
(a) 
oO 
cos” * (9-Bo dg = 
oO 
