I suppose what is desired is an explanation in layman's terms. So, let's forget about this...
Radar is a way to touch. In the context of radar signal generation methodology, phase is the ability to oscillate a "touch value" anywhere between +X and -X [x...0...-x], corresponding simultaneoulsy, and seprately to both signal frequency and amplitude. Two signals of equal freuqency and equal amplitude, but opposite phase -- cancel. By manipulating phase, with the help of some serious software, Phased Array Radar (of which AEGIS is an example) may "touch" with greater sensitivity. The "Array" aspect is, while essential to the schema, not the factor that accounts for the increased resolution, but the manipulation of phase. Don't be confused by the seeming resemblance of radio telescope systems. They "work" better than single-dish telescopes simply because they can resolve to as high a wavelength as (approx.) 10% of the array's diameter.
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