A radiation pattern is a graphical representation of the radiation properties of an antenna or other source as a function of space. It defines the variation of the power radiated by an antenna as a function of the direction away from the antenna. The radiation pattern is a three-dimensional figure and represented in spherical coordinates (r, θ, Φ) assuming its origin at the center of the spherical coordinate system. The far-field radiation pattern may be represented graphically as a plot of one of a number of related variables, including the field strength at a constant (large) radius (an amplitude pattern or field pattern), the power per unit solid angle (power pattern), and the directive gain. The radiation pattern can be field patterns or power patterns, and they are plotted on logarithmic or commonly on dB scale. The radiation pattern is important in antenna design because it describes how the antenna radiates energy out into space or how it receives energy.