if youāre not familiar with this, itās a radar installation which can scan a beam across the sky without moving. each panel is made up of lots and lots of small, stationary antennas, which each emit the same signal but slightly out of phase (i.e. with different timing, so the peaks and troughs of the emitted energy are earlier or later from one antenna to the next).
as the waves propagate, they interfere constructively in one directionāthe one where the beam is being aimedāand destructively in every other direction. so in effect you have a single big antenna that you can steer way way faster than you could move a physical antenna anywhere near that size, just by adjusting the timing of the signals going to the antennas in the array. see? cool as hell. more here.