Daniel F. Sievenpiper

TL;DR: In this paper, a new type of metallic structure has been developed that is characterized by having high surface impedance, which is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements and distributed in a two-dimensional lattice.

TL;DR: In this article, a periodic surface texture is used to alter the electromagnetic properties of a metal ground plane by covering the surface with varactor diodes, and a tunable impedance surface is built, in which an applied bias voltage controls the resonance frequency and the reflection phase.

TL;DR: In this paper, an artificial impedance surface that is implemented as an array of sub-wavelength metallic patches on a grounded dielectric substrate is designed to scatter a known input wave into a desired output wave.

TL;DR: Metasurfaces have been a topic of significant research and are used in various applications due to their unique ability to manipulate electromagnetic waves in microwave and optical frequencies as mentioned in this paper, which has the advantages of light weight, ease of fabrication, and ability to control wave propagation both on the surface and in the surrounding free space.

TL;DR: An antenna having at least one main element and a plurality of parasitic elements is considered to have a coupling element or devices associated with them, the coupling elements or devices being tunable to control the degree of coupling between adjacent elements.