Enter your Input Power to Antenna, Power Unit, Antenna Gain, Distance from Antenna, and Distance Unit into this RF Power Density Calculator to find the Power Density at a given point in space, plus Power Density (W/m²) and Effective Radiated Power — handy for checking RF exposure levels or verifying antenna performance at specific distances.
Power Density
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Power Density (W/m²)
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Effective Radiated Power
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RF power density is the amount of electromagnetic energy per unit area at a given distance from an antenna. It's measured in mW/cm² or W/m² and is crucial for RF safety compliance, ensuring exposure levels meet regulatory limits.
RF power density follows the inverse square law - it decreases with the square of distance. Doubling the distance reduces power density to one-fourth of the original value.
Antenna gain is typically specified in dB by the manufacturer. Common values range from 0 dB for omnidirectional antennas to 20+ dB for high-gain directional antennas. Check your antenna datasheet for the exact gain figure.
The calculator automatically handles conversions. Common conversions: 1W = 1000mW, 0 dBm = 1mW, 30 dBm = 1W, 0 dBW = 1W. Use the power unit dropdown to select your preferred input format.
Safe exposure limits vary by frequency and jurisdiction. FCC guidelines typically range from 1-10 mW/cm² for general public exposure. Always consult current regulatory standards for your specific frequency and application.
This calculator assumes maximum radiation in the antenna's main beam direction. Real antennas have radiation patterns that vary with angle, so actual power density may be lower off the main beam axis.
This calculator is designed for far-field calculations where distance is much greater than antenna dimensions. For near-field calculations (very close to large antennas), more complex analysis methods are required.