A two-element array consisting of two isotropic antennas separated by a distance d along t...

A two-element array consisting of two isotropic antennas separated by a distance d along the z-axis is placed in a coordinate system whose x-axis points eastward and whose v-axis points toward the zenith. If a0 and a1 are the amplitudes of the excitations of the antennas at Z = 0 and at Z = d, respectively, and if δ is the phase of the excitation of the antenna at z = d relative to that of the other antenna, find the array factor and plot the pattern ill the x-z plane for the following: