Consider a submarine in water (Er = 4,0 = 0) with a thin linear antenna transmitting to a plane in free space directly overhead (see the diagram). The total length of the antenna is /2. a) Calculate the E-Field at the plane when it is directly overhead. Assume all radiation from the antenna is in the far field. Choose and clearly identify your coordinate system to simplify the problem as much as possible. Now assume the plane has flown a short distance such that the electromagnetic wave which reaches the plane has an incident angle on the water-air boundary of 100 (see the diagram to the right). How far has the plane traveled? ?m = 1 Hy = 1 = 1 Hr = 1 = 4 Hy = 1 r = 4 Hy = 1 b) Calculate the Poynting vector of the electromagnetic wave at the location of the plane. 10 100 m Ji12 100 m 100 m Fi/2 100 m d) By what percentage is the electric field attenuated at the plane's new location in comparison to part a)?