In telecommunications, aperture-to-medium coupling loss is the difference between the theoretical antenna gain of a very large antenna, such as the antennas in beyond-the-horizon microwave links, and the gain that can be realized in practice. Note 1: Aperture-to-medium coupling loss is related to the ratio of the scatter angle to the antenna beamwidth. Note 2: The "very large antennas" are referred to in wavelengths; thus, this loss can apply to line-of-sight systems also.
See also Coupling loss
References This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22. (in support of MIL-STD-188).