Design of Beamforming Metasurfaces Using Microwave Network Theory

The paper proposes a design technique for directly-fed beamforming metasurfaces using microwave network theory. The beamformning meta surface consists of a grid of unit <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ce</sup>lls that are connected to ports. The impedance matrix, which relates the voltage and current at the unit cell ports, is extracted from a full-wave solver to accurately model electromagnetic coupling. Reactive loads are connected to the ports and optimized using network theory to provide beam steering and shaping. This technique is validated using an aperture-coupled grid of unit cells. A design example is presented to produce a broadside Gaussian amplitude. The example is verified using Ansys HFSS with the reactive loads attached to the metasurface, demonstrating the ability to produce desired radiation patterns.