Q$25$ Design an $8-$elements ordinary end five amay with element

placell along z$-$axis, a distame $d$ apant. for $d=\frac{1}{2}$

a$)$ Angles in degree where nulls of Af occur.

b$)$ Angles in clegree where maximum of $Af$ occuir:

c$)$ prog phase excitaio

d$)(H)n$

e$)$ Do in $d_B$