Antenna Pattern Explorer
Learn to read an antenna datasheet: azimuth and elevation patterns, beamwidth, gain and front-to-back ratio, in 2D or turning in 3D, then see where the beam lands on the floor.
How to use this tool controls and what to look for
Pick an antenna and read its datasheet patterns, then mount it and see where the beam lands on the floor.
Controls to change
- Type: choose a Dipole, Collinear omni, Patch, Sector, Yagi or Custom antenna.
- Horizontal beamwidth: for Custom, set the beamwidths and the Front-to-back ratio.
- Plot scale: switch between dB (as on datasheets) and Linear power.
- Datasheet view: switch between 2D cuts and 3D. Drag the 3D pattern to turn it.
- Compare with: lay a second antenna's pattern over the first.
- Mount: choose Ceiling, pointing down, or Wall, pointing out, then set the Mounting height, Downtilt and Transmit power.
What to look for
- Gain is focus, not extra power: a narrower beam puts more signal in one direction and less everywhere else.
- A pattern plotted in dB looks much fatter than it really is. Switch to Linear power to see the true shape.
- The azimuth plot is the view from above. The elevation plot is the view from the side.
- Mounting height and downtilt decide where the beam meets the floor and where the dead spots are.
About this tool
Learn to read an antenna datasheet. Pick a dipole, a collinear omni, a patch, a sector or a Yagi, or set your own beamwidths, and see its azimuth and elevation patterns with the −3 dB points that define the beamwidth, its gain and its front-to-back ratio. Switch between the dB scale used on datasheets and linear power, turn the whole pattern in 3D, and compare two antennas. Then mount the antenna on a ceiling or a wall, set its height and downtilt, and see from above and from the side where its signal lands on the floor.
What you'll learn
- How to read the azimuth and elevation plots on an antenna datasheet
- What beamwidth, gain in dBi and front-to-back ratio mean, and why gain is focus rather than extra power
- Why a pattern plotted in dB looks fatter than it really is
- How mounting height and downtilt decide where the beam meets the floor
Common questions
What is antenna beamwidth?
The angle between the two directions where the signal is 3 dB below the peak, that is half the power. A datasheet gives it for the horizontal (azimuth) and vertical (elevation) planes; the narrower the beam, the higher the gain.
How much gain does a dipole have?
A half-wave dipole has about 2.15 dBi: it sends equally in every horizontal direction but little straight up or down, so its peak is 2.15 dB stronger than an antenna that sends equally everywhere.
Why do patterns look different in dB and linear?
A dB scale compresses big differences, so a direction that is 10 dB weaker still looks close to the peak. On a linear power scale the same direction has only a tenth of the power, and the beam looks much narrower.
Free for private and educational use. This interactive model is a simplified teaching aid and may contain mistakes. It is provided as is, without warranty. Use it to understand the concepts, not as a substitute for a site survey, vendor documentation or professional design advice.