Dipole · Yagi · Patch · Phased Array · Polar plot · dBi
Theoretical reference; 100% efficiency
An antenna's radiation pattern describes how it distributes transmitted power across all directions. The pattern is plotted in polar coordinates where radius = relative gain (in dB or linear). An isotropic antenna (theoretical) radiates equally in all directions. A half-wave dipole concentrates radiation in a torus perpendicular to its axis. A Yagi-Uda array adds parasitic directors and reflectors that create a highly directional beam. Phased arrays steer the beam electronically by applying progressive phase shifts to each element, exploiting constructive and destructive interference of the array factor.
Click the antenna type buttons to switch patterns. For Phased Array, drag the Steering Angle slider to electronically steer the main beam without moving any hardware. Toggle between linear and dB scale — the dB view shows side lobe levels clearly. The HPBW (Half-Power Beam Width) annotation shows the −3 dB angular width of the main beam. Note how increasing the number of array elements narrows the beam and increases gain.
Modern 5G base stations use massive MIMO phased arrays with 64–256 antenna elements, steering beams to individual users thousands of times per second. The world's largest phased array radar (HAARP in Alaska) uses 180 crossed-dipole antennas to study the ionosphere. Satellite dish antennas achieve gains of 30–50 dBi by using a parabolic reflector to focus energy into an extremely narrow beam — sometimes less than 0.5° wide.