Free space path loss
L = fspl(R,lambda)
Propagation distance in meters
Wavelength in meters. The wavelength in meters is the speed of propagation divided by the frequency in hertz.
Path loss in decibels. L is a nonnegative number. The minimum value of L is 0, indicating no path loss.
Calculate free space path loss in decibels incurred by a 10 gigahertz wave over a distance of 10 kilometers.
lambda = physconst('LightSpeed')/10e9; R = 10e3; L = fspl(R,lambda);
The free-space path loss, L, in decibels is:
This formula assumes that the target is in the far-field of the transmitting element or array. In the near-field, the free-space path loss formula is not valid and can result in a loss smaller than 0 dB, equivalent to a signal gain. For this reason, the loss is set to 0 dB for range values R ≤ λ/4π.