$(15$ points$)1.$ A $900MHz$ wireless LAN access point antenna $($Tx$)$ is mounted on a wall $3$

$m$ above the floor. A $2m$ high metal partition separates a user $(Rx)$ from the access point as

shown in the figure. For this problem you can neglect reflections.

$($a$)$ If the user's antenna is $h=1\mathrm{.}5m$ above the floor, what is the excess loss due to diffraction

from the partition? Note that the figure is not to scale. See expanded plot of the diffraction

function on the next page.

$($b$)$ If the user can increase the antenna height to a level where the Tx antenna is in view, how

much does the line$-$of$-$sight path have to clear the partition so that essentially a free space signal

level received? $($You do not have to calculate h$.)$