Question

3. Consider a square waveguide of side 2L, centered at the origin, with axis running parallel to the z-axis. The square cross-section is parallel to the xy-plane, so the 4 sidewalls lie at x = ±L and y = ±L. Consider the TE mode given by Eo x s in cos (kz - wt) = Eo-y sin (-) cos (kz-wt)- sin (kz -wt = (a) Find the time average of the Poynting vector, i.e. the average energy flux per unit area per unit time. (b) Integrate this over the cross section, to give the average energy flux per unit time down the waveguide (c) Calculate the speed at which energy propagates down the waveguide, expressed as a function of w, c, and L. Hint: calculate the energy per unit length stored in the electromagnetic field, and combine this with your answer to part (b).

Answer 1

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