Discrete-dipole approximation model for control and optimization of a holographic metamaterial antenna.

Since the discovery of materials with negative refractive index, widely known as metamaterials, it has been possible to develop new devices that utilize a metamaterial's ability to control the path of electromagnetic energy. Of particular promise, and already under intensive development for commercial applications, are metamaterial antennas for satellite communications. Using reconfigurable metamaterials in conjunction with the principles of holography, these new antennas can electronically steer the high gain antenna beam required for broadband communications while not having any moving parts, being thinner, lighter weight, and less expensive, and requiring less power to operate than conventional alternatives. Yet, the promise of these devices will not be realized without efficient and effective control and optimization. Toward this end, in this paper a discrete-dipole approximation (DDA) model of a waveguide-fed planar metamaterial antenna is derived. The proposed model is demonstrated to accurately predict the radiation of a two-dimensional metamaterial at a much reduced computational cost to full-wave simulation and at much greater fidelity than simpler models typically used in the field. The predictive capabilities of the derived DDA model opens possibilities for model-based control design for optimal beam steering.