Consider the linear antenna oriented along the z direction current given by I( z )=I 0 cos(p z / d ), with | z | less or equal d /2. The length of the antenna is d .
(a) Find the linear charge density r( z ) (assume the time dependence is governed by the frequency w, as usual).
(b) Find dP/dW in terms of the impedance of free space Z 0 , the current amplitude I 0 , the wavevector k , and d .
(c) Find the total power radiated.
(d) From the plane waves produced by this oscillating electric dipole, consider those propagating along the positive y -axis. In what direction points the magnetic field H and in what direction the electric field E ?
