captured by the individual antennas. Placing two high gain antennas very close to each other (less than a wavelength) does not buy twice the gain, for example. Conversely, if the antenna are more than a wavelength apart, there are photons that fall between the elements and are not collected at all. This is why the physical aperture size must be taken into account.

Let's assume a 16×16 un-tapered standard rectangular array (which means that elements are spaced at .) The array gain is dB. If the array were tapered, this value would