Q$8)(4$ Marks$)$ A uniform array of $20$ antennas with spacing $d=\frac{}{4}$ is fed with a current of the same magnitude but with a prooressive phase shift, i$.$e$.I_{1s}=\frac{I_o}{{?}_0},I_{2s}=\frac{I_o}{{?}_{}},I_3=\frac{I_o}{{?}_2},$dots Given that the array factor is

$|AF|=|\frac{sin(\frac{N}{2})}{sin(\frac{}{2})}|,=dcos+$

a$)$ Find the required current phase $$ that results in a maximum radiation at $=\frac{}{8}.$

Answer: $q,(1\mathrm{.}5$ mark$)$

b$)$ What is the magnitude of the array factor at the maximum radiation angle.

Answer:

$(0\mathrm{.}5$ mark$)$

xplanation $($Steps to find the answers$)$: $(2$ Marks$)$