  We combed the Koch snowflake fractal antennae in calibre design of
Five-hundred-meter Aperture Spherical radio Telescope (FAST), building a
conjecture of a second-order fractal primary reflectors to optimize the
orientated sensitivity of the telescope. Meanwhile, on the grounds of NASA
Science Working Group Report in 1984, we reexamine the strategy of Search for
Extraterrestrial Intelligence (SETI). The mathematical analysis of the radar
equation will be accomplished in the first section, aim to make it convenient
to design a receiver system that can eavesdrop on disturbing activities of an
extraterrestrial civilization, which according to the observable region of the
narrowband. Taking advantage of the inherent potential of FAST, we simulate the
theoretical detection of Kardashev Type I civilization by snowflake-selected
reflecting area.
