Question

14. A microwave transmitter at height a above a large lake transmits towards a receiver at the other end, located at height x. The microwaves reflecting from the water interfere with the microwaves arriving directly from the transmitter. Assume the lake width D is much larger than either a or x, and that the microwave wavelength is greater than or equal to a. Derive an expression that gives the values of x for which the signal at the receiver is maximum. Hint: you might like to use the binomial approximation to avoid messiness, and also pay attention to the phase of the microwaves off the water.

Answer 1