Question $4(30$ Marks$)$

$($a$)$ A half$-$wave dipole fed by a $\backslash (50-\backslash$Omega $\backslash )$ transmission line, calculate $(10$ marks$)$ the reflection coefficient and the standing wave ratio.

$($b$)$ A $1-$m$-$long car radio antenna in the AM frequency of $1\mathrm{.}5$ MHz $.(10$ marks$)$ How much current is required to transmit $4$ W of power?

$($c$)$ The transmitting and receiving antennas are separated by a $(10$ marks$)$ distance of $\backslash (200\backslash$lambda $\backslash )$ and have directive gains of $25$ and $18$ dB respectively. If $5$ mW of power is to be received, calculate the minimum transmitted power.