It does do directional steering. No active array components or physical movement are needed.

> If the output ports are connected to individual antennas in an antenna array, this allows shaping the beam in different directions by switching which input port the signal is sent to.

From TFA.

Presumably the geometrical shape of the lens is dictated by solving for useful phase shifts for different input points. Otherwise you could just use a bunch of delay lines.

I wonder if anybody's ever designed a 3D version of this. You might get a wider range of inputs, or more precise steering, by shaping the delays on a non-Euclidean (curved) surface (like a sphere or a saddle).