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

Abstract

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.

Experimental Synthetic Aperture Radar With Dynamic Metasurfaces

“…In this scenario, the waveguide mode can be thought of as a reference wave with the tuning states of the elements serving as a dynamically-reconfigurable computer-generated hologram [41]. In [19] and [42], this type of holographic analysis was applied to generate steerable, directive beams using a dynamic metasurface. While this notion provides a more rigorous and sophisticated approach to understand the aperture's performance, we can also consider the aperture from an array factor perspective to develop some rudimentary intuition.…”

Sidelobe Canceling for Reconfigurable Holographic Metamaterial Antenna

“…A discrete dipole approximation-based model (DDA model) of the metamaterial antenna captures all the effects mentioned above and has been demonstrated to more accurately predict the far-field radiation pattern of the antenna than other models typically used in metamaterial modeling, while being fast enough for rapid iteration for optimization [19]. Thus, in this work we use a DDA model of the antenna to demonstrate our optimization scheme.…”

“…Thus, in this work we use a DDA model of the antenna to demonstrate our optimization scheme. Refer to [19] for details on the properties and parameters of this model. In this work, the planar MSA is simplified to a one-dimensional array; a single row of meta-atom resonators.…”

Analysis of a Waveguide-Fed Metasurface Antenna

“…The waveguide-fed metasurface is an emerging concept for aperture antenna design that leverages resonant, subwavelength, radiating elements to generate desired radiation patterns for applications including beam forming for satellite communications [1][2][3][4], radio frequency (RF) imaging [5][6][7], wireless power transfer [8,9] and synthetic aperture imaging [10][11][12]. The use of subwavelength scattering or radiating elements over an aperture enables the effective electric and magnetic current distributions to be conceptualized as continuous, motivating a holographic design approach for the antenna as opposed to the discrete mathematics that would characterize phased arrays and electronically scanned antennas (ESAs) [13][14][15][16].…”