High Index Multi-Layer Metasurfaces for Broadband Polarization Control
Abstract
The initial objective of this effort was to develop compact devices for controlling the phase and polarization properties of near-infrared radiation. These devices were to be based on cascaded subwavelength gratings consisting of high-contrast dielectrics - such as silicon and silicon oxide -and be fabricated using a local oxidation of silicon (LOCOS) technique. Following difficulties in fabricating multilayer structures using the proposed LOCOS technique, we investigated the design and fabrication of the cascaded grating structures using an additive manufacturing process (ceramic stereolithography) to enable monolithic fabrication without separate assembly or intermediate processing between layers. In ceramic stereolithography, an ultraviolet light source is used to selectively cure a photoreactive ceramic particle suspension layer-by-layer, resulting in a "green" part that is subsequently pyrolyzed and sintered to remove polymer components and leave a pure, dense ceramic structure. The process can produce high accuracy parts with small, high-contrast features that are well-suited to subwavelength patterning at microwave frequencies. Working closely with ceramic stereolithography manufacturers, we designed, fabricated, and experimentally characterized several broadband, multiband, and multifunctional polarization-conversion devices for the technologically important Ku and Ka microwave frequency bands. We also investigated other varieties of all-dielectric metastructures, including an all-dielectric implementation of transmissive Huygens' metasurfaces based on resonant ceramic rods embedded within a ceramic/air lattice. Using these concepts, we designed a metasurface-based, wide-angle-scanning dome antenna that steers beams towards the horizon while minimizing scan loss and validated the design using full-wave simulations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 02, 2024
- Accession Number
- AD1230271
Entities
People
- Anthony Grbic
Organizations
- Board of Regents of the University of Michigan