The strength of a reflected radar signal generally decreases with the fourth power of distance: r-squared to the reflector, and r-squared back from the reflecto

The strength of a reflected radar signal generally decreases with the fourth power of distance: r-squared to the reflector, and r-squared back from the reflector (assuming more-or-less uniform backscattering). Which means that a low radar signature is usually still detectable, the object just needs to get moderately closer. So being stealthy in the radar spectrum is pretty difficult, and I often wonder if stealth planes are mostly a means to transfer money from the state to defense companies.