Fundamentals of Engineering Electromagnetics 1st Edition by David Cheng

Exercise 46

An electromagnetic wave is to propagate along an air-filled a × b rectangular waveguide at the dominant mode. Assume a = 2.50 (cm) and the usable bandwidth to be between 1.15( f c ) 10 and 15% below the cutoff frequency of the next higher mode.
a) Calculate and compare the permissible bandwidth for b = 0.25 a , b = 0.50 a , and b = 0.75 a.
b) Calculate and compare the average powers transmitted along the three guides in part (a) at 7 (GHz) if the maximum electric intensity is 10 (kV/m). Neglect the losses.