- Antenna factor
In

telecommunications , the**antenna factor**"AF" (unit: 1/m) is defined as theratio of the incidentelectromagnetic field strength "E" (units: V/m or µV/m) to thevoltage "V" (units: V or µV) on the line connection of an antenna:: $AF\; =\; frac\; EV$

If all quantities are expressed logarithmically in

decibel s instead ofSI unit s, the above equation becomes: $AF\_\{mathrm\{dBm\}^\{-1\; =E\_mathrm\{mathrm\{dBV/m\; -\; V\_\{mathrm\{dBV\; =E\_mathrm\{mathrm\{dB\}mumathrm\{V/m\; -\; V\_\{mathrm\{dB\}mumathrm\{V$

In a 50 Ω system, the antenna factor is related to the

antenna gain "G" and the wavelength λ via:: $AF\; =\; frac\{9.73\}\{lambda\; sqrt\{G\}\; \}$

The variable G means antenna gain (dimensionless) and it can be written in terms of effective aperture A to obtain the final expression considering the

impedance of free space (376.6Ω) and the load as 50Ω. The antenna effective aperture can be written as A = (λ^{2}G)/4π.**References*** [

*http://www.microindustrie.com/fcc/recaf.htm MicroIndustrie Antenna Factor*] (link broken)

* [*http://www.djmelectronics.com/articles/emc-antenna-parameters-p3.html Interpreting Antenna Performance Parameters for EMC Applications*] An excellent page with summaries of all the relevant equations

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