This Demonstration plots the normalized E-radiation pattern of a center-fed linear dipole antenna with sinusoidal current distribution on the axis. Three of the sides of the cube correspond to intersections with the coordinate planes. There is a one-to-one correspondence between , , and the colors red, green, blue. The length/wavelength (Lpwl) of the dipole ranges from 0.1 to 10 in steps of 0.1. The default 3D evaluation is done at every 3°. 2D evaluation is always carried out at 1°. A small delay may be needed to get a smooth overall picture.

The normalized radiation pattern for the electric field of a symmetrical center-fed linear dipole antenna on the axis with sinusoidal current distribution is given by:

, where , .

is the second coordinate of the spherical system (, , ), with 0 at axis and at - (this is the variable t in the RadiationPattern function). is the total length per wavelength of the dipole (Lpwl variable). {E}_{max} is the maximum value of {E} for each one dipole. So,

Mesh and Opacity controls correspond to the well-known options of Mathematica 7, while the goal control stands for Mathematica's PerformanceGoal.

The "step [°]" control changes the number of plot points for the 3D radiation pattern. The initial value of 3° results in a smooth object. SphericalPlot3D was chosen, instead of RevolutionPlot3D or ParametricPlot3D, since it was faster.