Power (dBm) to Field Strength (dBuV/m)

This calculator converts Power in dBm at a receiver input to Field Intensity deciBels-microVolt-Per-Meter (dBuV/m) at the antenna.

The tool is useful when a measurement is made using a calibrated spectrum analyzer or receiver (in dBm) with an antenna connected to its input port. It provides the field strength in dBuV/m at the antenna.

This tool requires as input

  • Power at the input to the receiver (dBm)
  • Impedance (ohm)
  • Antenna gain (dBi)
  • Frequency of operation (Hz)

Formula

AF = 20*Log10(9.73/(λ√G))

VdBμV = PdBm + 10*Log10(Z) + 90

EdBμV/m = VdBμV + AFdB/m

Example Calculation

For

  • Input power of -60 dBm,
  • Input impedance of 50 ohm,
  • Antenna gain of 3 dBi,
  • Frequency = 1000 MHz

The field intensity is calculated to be 74.25 dBuV/m.

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