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Antenna Factor Formula:
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The Antenna Factor (AF) is a parameter that relates the electric field strength to the voltage received at the antenna terminals. It is commonly used in electromagnetic compatibility (EMC) testing and antenna measurements to convert measured voltages to field strengths.
The calculator uses the Antenna Factor formula:
Where:
Explanation: This formula converts antenna gain and frequency into the antenna factor, which represents how much the antenna attenuates the incoming field.
Details: Accurate antenna factor calculation is essential for precise electromagnetic field measurements, EMC compliance testing, and antenna calibration. It ensures that field strength measurements are correctly interpreted from received voltage readings.
Tips: Enter frequency in MHz and antenna gain in dBi. Both values must be valid (frequency > 0).
Q1: What is the relationship between antenna factor and gain?
A: Antenna factor and gain are inversely related. Higher gain antennas typically have lower antenna factors, meaning they are more efficient at converting field strength to voltage.
Q2: Why is the constant 29.79 used in the formula?
A: The constant 29.79 comes from the conversion factors needed to relate field strength in V/m to received power, accounting for the impedance of free space and unit conversions.
Q3: How does frequency affect antenna factor?
A: Antenna factor generally increases with frequency. The 20*log10(f) term in the formula shows this logarithmic relationship.
Q4: What are typical antenna factor values?
A: Antenna factor values typically range from 10-50 dB/m, depending on the antenna type and frequency range.
Q5: Can this formula be used for all antenna types?
A: This formula provides a general conversion, but specific antenna designs may have variations. Always refer to manufacturer specifications for precise antenna factor values.