Free-space components for microwave transmission

The ability to guide, manipulate, and process radio- and microwave-frequency radiation is limited by two major factors. From a fundamental viewpoint, the intensity and width of a beam propagating in a free space, as well as the angular and range resolution of radar systems, are limited by diffraction. From a practical viewpoint, free-space beam processing is hindered by a lack of free-space instrumentation for beam focusing, steering, or (de)-multiplexing. As a result, modern radar systems often employ advanced signal processing and detection techniques aimed at enhancing target and feature estimation. Here, we propose several new structures founded upon the emerging plasma filament-based approach to metamaterial design that are aimed at addressing such problems and providing tools for greater capability in microwave transmission than has been possible in the past. In particular, we have designed new structures formed from arrays of plasma filaments in air that leverage the anisotropic behavior of such arrays to address the limits of angular and range resolution, as well as the lack of free-space components for processing radiation in wireless communications.