Reconfigurable huygens' refractors based on material tuning

A metasurface, comprising:

• an array of unit cells arranged to transmit a beamformed instance of an electromagnetic wave impinging on the metasurface, the array of unit cells comprising a subarray comprising at least some of the unit cells, the subarray of the at least some of the unit cells comprising:
• a first unit cell, comprising:
• a first upper metallic resonator,
• a first dielectric material below the first metallic resonator, and
• a first lower metallic resonator below the first dielectric material;
• and
• a second unit cell, comprising:
• a second upper metallic resonator,
• a second dielectric material below the first metallic resonator, and
• a second lower metallic resonator below the first dielectric material,
• wherein a first phase response of the first unit cell is controllable, based on applying a first stimulus to the first dielectric material to determine a first refractive index of the first dielectric material, to cause the first unit cell to transmit a first instance of a first portion of the beamformed instance in a first direction based on the first refractive index;
• wherein a second phase response of the second unit cell is controllable, based on applying a second stimulus to the second dielectric material to determine a second refractive index of the second dielectric material, to cause the second unit cell to transmit a second instance of a second portion of the beamformed instance in a second direction based on the second refractive index, and
• wherein the first portion of the beamformed instance transmitted in the first direction and the second portion of the beamformed instance transmitted in the second direction constructively interfere as part of the beamformed instance.