APERTURE TO MEDIUM COUPLING LOSS

The difference between the theoretical gain of a very large antenna , such as the antennas in beyond-the-horizon microwave links, and the gain that can be realized in operation . 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. ( 188 )