This calculator applies the Friis equation to estimate the power received by an antenna based on the transmitted power, the gain of the antennas and the distance between them. It is essential for analyzing the performance of wireless links and the propagation of RF signals.
Useful for telecommunications engineers, RF system designers, and students working on radio link modeling and free space path losses.
Formula
Pr = (Pt × Gt lin × Gr lin × λ²) / (4 × π × R)²
Explanation of the formula
- Pt: power emitted by the transmitting antenna (in watts).
- Gt and Gr: gains of the transmitting and receiving antennas, converted to linear values from dBi using 10^(GdBi/10).
- λ: wavelength corresponding to the transmission frequency.
- R: distance between the antennas (in meters).
- This equation evaluates the power received in an environment without obstacles, that is to say in free space.
Example: calculation of power received for a 2.4 GHz link over 10 m
Input : Pt = 1 W, Gt = 2 dBi, Gr = 2 dBi, f = 2.4 GHz, R = 10 m
Output : Pr ≈ 0.0006 W (or -32.2 dBm)
Benefits and uses
- Evaluates free space path losses in RF communications.
- Useful for sizing Wi-Fi, microwave and satellite links.
- Facilitates link budget estimation when designing wireless networks.
- Allows you to compare the performance of antennas at different frequencies.