Friis Transmission Calculator

dBi
dBi
m

This calculator determines the received power in a wireless communication link using the Friis transmission equation. It helps evaluate link performance based on transmitter power, antenna gains, distance, and wavelength.

Formula

Pr = (Pt × Gtlin × Grlin × λ²) / (4 × π × R)²

Formula Explanation

  • Pt = Transmitted power
  • Gtlin and Grlin = Antenna gains (converted from dBi to linear using 10^(GdBi/10))
  • λ = Wavelength (m)
  • R = Distance between antennas (m)

Example

Input: Pt = 10 W, Gt = 15 dBi, Gr = 10 dBi, λ = 0.05 m, R = 100 m

Result: Pr ≈ 0.0125 W

Who uses it

Useful for RF engineers and network designers calculating signal strength and link budget for wireless systems.