This calculator determines the power density radiated by an antenna based on input power, gain and distance. It evaluates the strength of the electromagnetic field at a given distance to ensure compliance with exposure limits and optimize signal coverage.
Ideal for RF engineers, wireless system designers, and measurement technicians who need to estimate power density around antennas in test or deployment environments.
Formula
S = (P × G) / (4 × π × R²)
Explanation of the formula
- S represents the power density (mW/cm²).
- P is the power applied to the antenna (in mW or W).
- G is the antenna gain, expressed as a linear value or converted from dB.
- R is the distance between the antenna and the field evaluation point.
- The formula follows from the principle of conservation of the radiated power distributed over a sphere of radius R.
Calculation of antenna power density 100 W at 10 m with gain 10 dB
Input : P = 100 W, G = 10 dB, R = 10 m
Output : Power density ≈ 0.0796 mW/cm²
Benefits and uses
- Evaluates compliance with RF safety standards.
- Useful for antenna design and placement.
- Allows you to estimate the coverage or range of a signal.
- Essential for cell and radio site planning.