The Friis Transmission conversion calculator computes the received power over a wireless link based on transmitted power, antenna gains, frequency, and distance. It applies the Friis transmission equation to estimate free-space path loss and signal strength, helping engineers analyze link budgets for radio and microwave systems.
Formula
Pr = (Pt * Gt_lin * Gr_lin * λ²) / (4 * π * R)²
Formula Explanation
- Pr is the received power in watts.
- Pt is the transmitted power in watts.
- Gt_lin and Gr_lin are the transmitter and receiver antenna gains in linear scale.
- λ is the wavelength of the transmitted signal, equal to the speed of light divided by frequency.
- R is the distance between the antennas in meters.
- Gt and Gr values in dBi are converted to linear form using 10^(GdBi/10).
Uses of this calculator
- Evaluating link budgets in wireless communication systems.
- Estimating received power levels in line-of-sight radio links.
- Determining antenna gain requirements for long-distance transmissions.
- Educational analysis of free-space path loss and propagation models.
What is the received power for 1 W transmission at 2.4 GHz over 100 meters?
Input: Pt = 1 W, Gt = 10 dBi, Gr = 10 dBi, f = 2.4 GHz, R = 100 m
Output:
- λ = 3×10⁸ / 2.4×10⁹ = 0.125 m
- Gt_lin = 10^(10/10) = 10
- Gr_lin = 10^(10/10) = 10
- Pr = (1 * 10 * 10 * 0.125²) / (4 * π * 100)² = (100 * 0.0156) / 1.579×10⁶ = 0.00156 / 1.579×10⁶ = 9.87×10⁻⁷ W
- Received Power = 0.987 µW