Concentration of Radiation in a Single Point

In MASC (and in most wave propagation models), an antenna is concentrated in a single point of radiation, and the pattern (far field pattern) of the antenna (obtained from the manufacturer of the antenna) will be used for the computation.

In reality, this is different. Antennas have a given mechanical size and are radiating not only from a single point – but from the whole aperture.

MASC reduces the antennas to single point radiators. The antenna pattern of the individual antenna is applied to the single point radiator. So, radiation is concentrated in a single point. But the mechanical size of the antenna and its radome is also considered in MASC - for the interaction (transmission, reflection, diffraction) with signals radiated from other antennas.

The concentration of the radiation into a single point is required because of the patterns of the single antennas. All patterns of these commercial antennas are far field assuming the radiation from a single point. So, considering the actual mechanical aperture would require new patterns which are not available for most antennas. With the concentration of the radiation to a single point, the error, Error! The reference source is not found, is included in the results.

Figure 1. Comparison between single point radiation (on the left) and actual radiation (to the right).

The error shown in Figure 1 is big if the size of the antennas is large and the distance between them is small. As soon as the distances between the antennas are multiples of the antenna size, the error can be neglected.