P(xo , Yo ) 
Figure 7. Source and a line array. 
is not difficult to evaluate. In this case (letting 
E(x) = constant) 
Lf[2 sin(T 1 (cosa- Cosa, )) 
R= exp jizx(cosa-Ccosag) } dx = Lee ah Me AD 
ee ct (cosa- Cosa, ) 
If this result is normalized, and if q = 90°-9, then 
sin(Zz (sing- sing, )) 
= F- (12) 
wi (sing- sing, ) 
Ry 
This result can also be obtained if equation (8) is norma- 
lized and Wd>L; then, equation (8) approaches (12). This 
can be shown by using L' Hopital's rule. 
25 
