Calculate 3db Beamwidth

The calculator finds the 3dB bandwidth and cutoff frequency (low-pass and high-pass) of an antenna.


Enter Diameter:  meter
Enter Frequency: GHz



3 dB Beamwidth:  degrees
A cutoff frequency is a border in a system's frequency response at which energy flowing through the system starts to decrease or reflected without being transmitted. The 3 dB beamwidth of the antenna can be defined as the angular width of the radiation pattern, including beam peak maximum, between points 3 dB down from maximum beam level.
Beamwidth = 70λ / D
λ = Wavelength,
D = Diameter
The 3dB gain antenna
The 3dB also known as half power gain antenna is the compromise in suburban and general settings. The frequency response of a device /circuit describes its operation over a specified range of signal frequencies by showing how its gain, or the amount of signal it lets through changes with frequency.