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Antenna Radiation Patterns

Radiation pattern diagrams for common antenna types showing relative gain and directivity.

Uniform in all directions
Isotropic RadiatorTheoretical antenna that radiates equally in all directions in three dimensions. Used as a reference for gain (dBi). No real antenna is truly isotropic.
Gain:0 dBi (reference)
Polarization:N/A
Broadside pattern Max
Half-Wave DipoleTwo-element antenna fed at the center. Figure-8 pattern in the azimuth plane, omnidirectional in the elevation plane perpendicular to the antenna axis.
Gain:2.15 dBi
Polarization:Linear (along axis)
Omnidirectional (azimuth)
Quarter-Wave VerticalVertical antenna over a ground plane. Omnidirectional in azimuth with low-angle radiation. Commonly used for VHF marine and land mobile communications.
Gain:2.15 dBi (over ground plane)
Polarization:Vertical
Lower angle than λ/4
5/8 Wave VerticalVertical antenna 5/8 wavelength long. More gain than quarter-wave with lower radiation angle, improving long-distance coverage. Common in VHF/UHF mobile antennas.
Gain:4–5 dBi
Polarization:Vertical
R D Dir High F/B ratio, forward gain
Yagi-Uda (3 Element)Directional antenna with one driven element, one reflector, and one director. High front-to-back ratio. Used for point-to-point VHF/UHF links and amateur radio.
Gain:7–8 dBi
Polarization:Linear (along boom axis)
Extremely narrow beam, very high gain
Parabolic DishHigh-gain directional antenna using a parabolic reflector to focus energy into a very narrow beam. Used for satellite, microwave, and radar applications.
Gain:20–50+ dBi
Polarization:Depends on feed element
True omnidirectional azimuth
Ground Plane (Omnidirectional)Vertical antenna with horizontal radials forming a ground plane. Very common for base station VHF/UHF work. True omnidirectional pattern in azimuth.
Gain:0–3 dBi
Polarization:Vertical
Wideband directional
Log Periodic Dipole ArrayBroadband directional antenna with multiple dipole elements of increasing length. Maintains consistent gain and impedance over a wide frequency range.
Gain:6–9 dBi
Polarization:Linear
Note: Patterns shown are representative 2D cross-sections. Real antenna patterns are three-dimensional. Actual gain and pattern shape vary with antenna construction, ground conditions, and nearby objects.