Reconfigurable beam steering metasurface absorbers

An ultra-thin reconfigurable metasurface absorber consisting of a mushroom type artificial magnetic conductor (AMC) is proposed. By capacitively loading the unit cells the reflection phase can be shifted, allowing the metasurface to steer the incoming wave to the desired direction, behaving as a phase gradient absorber. A formula based on antenna array theory was used to determine the required phase shift needed to steer the main beam. A reduction of 30dBm² compare to a PEC ground plane was achieved for the design that steers the main beam to Φ=0° and θ= 15°, from the specular direction. Also, it was further shown that by incorporating resistors into the loaded structure the main beam width can be increased.