Problem 2: The radar system at an airport broadcasts 11 GHa microwaves with Pem = 150kW of power. An approaching airplane with an A = 31 m' cross section is d = 30 km away. Assume that the radar broadcasts uniformly in all directions and that the airplane scatters microwaves uniformly in all directions. What is the electric field strength of the microwave signal received back at the airport? a) Since the radar broadcasts uniformly in all direction, the intensity of the emitted signal at a distance d away from the source can be found as Jem = um. Assuming that the airplane scatters all the radiation that hits its cross section, how much energy per unit time will be available for the airplane to scatter? b) Now assume that the airplane itself is a point source of radiation with the power that you computed in the previous step. Find the intensity I of this radiation at the location of the airport (assume that during the signal propagation time the distance from the airplane to the airport did not change). From the relation compute the electric field strength in the received wave. (Answer E, = 5.2 x 10 *Vm ')