Phase characteristics of subwavelength antenna elements for efficient design of terahertz frequency and millimeter wave metasurfaces

In this paper the effects of subwavelength antenna resonator element dimensions on the anomalous reflection properties of metasurfaces operating in the millimeter wave and terahertz frequency regions are investigated. Such two-dimensional structures are finding uses as flat optics in a variety of applications including beam steerers, reflectarrays, and broadband, polarization-independent radar absorbers. Numerical simulations were performed to characterize the reflection phase of square resonators of varying dimensions for several metasurface and reflectarray designs. A simple empirical model is developed for efficient characterization of metasurface phase characteristics in lieu of expensive numerical simulation software.