This tool computes the Antenna Gain in dBi using:

- Antenna Factor (units: dB/m)
- Frequency of operation (units: Hz/kHz/MHz/GHz)

## Antenna Gain Formula

**Gain (dBi) = 20*Log _{10}(9.73/(λ***

**(10)**

^{AF/20}))Where

**λ**= Wavelength =**c/f**, where**c**is the speed of light and**f**is the frequency**AF**= Antenna Factor

## Definitions

**Antenna Factor**

It is the ratio of the electric field **E** (units: V/m or μV/m) to the voltage **V** (units: V or μV) induced across the terminals of an antenna.

The units are dB-per-meter or **dB/m**.

**Example Calculation**

A higher value of Antenna factor means an electric field induces a smaller voltage across the antenna. This implies or results in a lower value of antenna gain.

At 915 MHz,

- AF = 10 dB/m, the Antenna Gain is 19.45 dBi
- AF = 30 dB/m, Antenna Gain is -0.55 dBi

At a higher frequency of 2450 MHz for an AF of 10 dB/m, the Gain is 28 dBi.

The gain increases with frequency as according to the equation, it is inversely proportional to the wavelength. The wavelength at 2450 MHz is smaller than at 915 MHz (*Frequency to Wavelength Calculator*).

**Related Calculators**

- dBuV/m to dBm
- dBuV to uV
- dBm to V/m

**References**

[1] Wikipedia Antenna Factor