Bandwidth vs. Beamwidth: Understanding the Difference in Antennas

This article explains the difference between antenna bandwidth and beamwidth. Links to other antenna-related terms are also provided for further reading.

Antenna Bandwidth

Bandwidth, in general, refers to the portion of the electromagnetic spectrum a signal occupies. More specifically, it’s the difference between the upper and lower frequency limits of a signal or the operating range of RF equipment.

Antenna bandwidth, therefore, is defined as the frequency range over which an antenna can effectively transmit or receive information in the form of electromagnetic (EM) waves.

Example: If a half-wave dipole antenna transmits efficiently within the frequency range of 380 MHz to 470 MHz, then the bandwidth of the antenna is calculated as: 470 MHz - 380 MHz = 90 MHz.

Antenna Beamwidth

The radiation pattern of an antenna describes how electromagnetic waves are radiated in different directions. The directivity of an antenna, a measure of how focused its radiation is, is closely related to its beamwidth.

The angular width of the beam radiated by an antenna is typically measured by the HPBW (Half-Power Beam Width). In simpler terms, the beamwidth is the angular separation between two points on either side of the antenna’s main radiation lobe where the power has dropped to one-half of its maximum value.

These two points are located at one-half of the maximum power on the radiation pattern, often referred to as the 3-dB points.

Antenna Beamwidth

In essence, antenna bandwidth refers to the range of frequencies an antenna can operate on, while antenna beamwidth describes the angular spread of the antenna’s radiated power. They are distinct but important characteristics when considering antenna performance for a specific application.