Suppose that the radius of the sphere, R, is so large that only the radiation fields have an appreciable amplitude on its surface; recall that the radiation fields fall off with distance like 1/R (see...Suppose that the radius of the sphere, R, is so large that only the radiation fields have an appreciable amplitude on its surface; recall that the radiation fields fall off with distance like 1/R (see Equations (7.33)) , whereas the other field components fall off like 1/R 2 or 1/R 3 . For the case of dipole radiation in free space the Poynting vector has only an r-component because →E, →H are perpendicular to one another and also perpendicular to the direction specified by the …
