 Antenna beam pattern

An antenna beam pattern gives an antenna's directional response as a function of observation angle. A normalized power pattern divides radiation intensity by its peak; a field-amplitude pattern is its square root under a consistent impedance convention. The beam solid angle integrates the normalized power pattern over direction, so ideal directivity is $4\pi /{\Omega }_A$. A short dipole antenna has a power pattern proportional to ${\sin }^2\theta$, zero along its axis and maximum broadside. A narrow main lobe can coexist with sidelobes, so beamwidth alone does not specify the complete response.