In order to increase the power radiated,the length of the dipole has to be comparable to wavelength.

The most widely used dipole is approximately half a wavelength long.The pattern of a half-wave dipole is similar to that of a very short dipole-it is a figure of eight. The half-power beam width in the figure of eight is about 78°,which is narrower than that of the very short dipole.If the length of the dipole is increased to one wavelength in the figure of eight.the half-power beam width is nOW about 47°.