Abstract :
In this paper, the behavior of the human eye is analyzed obtaining different solutions for the main common trade-offs of antenna array systems, in particular regarding the angular resolution and the signal/noise ratio. Normally, to improve the angular resolution, more directive beams close to each other are needed. This is difficult because of the needed overlapping of the effective radiating areas of the different independent beams. On the other hand, to solve to problem of signal/noise ratio, a heterodyne detection is preferred instead a direct detection, since the power balance of the system ensures more margin at the receptor position. As we will see, the human eye uses very different techniques to solve these problems. In fact, both problems are solved with the same strategy, using many photo-receptors, cones, to create each of the beams, and re-using many of these cones for other neighboring beams. Thanks to this recycling technique of the cones, the effective radiating areas are practically overlapped and because are many cones detecting the same information coherently, the signal/noise ratio is also improved thanks to the spatial diversity used. The final result is well know for everyone and is that the "antenna system" of the human eye works really very well using very simple detection techniques.
