Usually, it is easier and more meaningful to plot a field in a number of principal planes in 2D in apolar plot. A plane containing the electric field vector is called the E-plane of the antenna. For adipole, φ = constant is the E-plane; the constant can be any angle since there is no field variationwith φ. The corresponding plot is a cross section of the doughnut:Similarly, a plane containing the H vector is called the H-plane. For the dipole, θ = 90◦is appropriate: