In this expression, ω is frequency in rads, λ is the wavelength in meters, ϵ is the permittivity of the material surrounding the antenna in Fm, ...In this expression, ω is frequency in rads, λ is the wavelength in meters, ϵ is the permittivity of the material surrounding the antenna in Fm, and (r,θ,ϕ) are the coordinates of a point specified in spherical coordinates. The electromagnetic radiation from each piece is found, and the principle of superposition is the idea that the radiation from the entire antenna is the sum of these pieces.
