Antenna Gain Linear to dB Calculator

This tool calculates the deciBel (dB) antenna gain from its linear value.

Calculator

• Enter either the linear value of Antenna gain relative to Isotropic or half-wave dipole
• The tool provides both the dBi and dBd values.

ðŸ”„ Antenna Gain dB to linear

Formula

GdBi = 10*Log10(Gi)

GdBd = GdBi – 2.15

where

• GdBi is the dB gain relative to an isotropic antenna
• GdBd is the dB gain relative to a half-wave dipole

Background

Antenna gain is a measure of how well an antenna can convert input power into radio waves headed in a specified direction, compared to a reference antenna. It is a key parameter in evaluating antenna performance because it directly affects the effective range and strength of the radio signal.

Antenna gain can either be specified as a linear or logarithmic quantity. As well the reference antenna is either an isotropic antenna or a half wave dipole.

Antenna Gain depends on its antenna factor and frequency of operation.

Example Calculation

A linear gain of 9 (for example) relative to an isotropic antenna gives

GdBd = 7.39 and GdBi = 9.54

Note GdBi = 7.39 + 2.15