Infrared Filters and Metamaterials Based on Frequency Selective Surfaces
Open Access
- Author:
- Bossard, Jeremy Alec
- Graduate Program:
- Electrical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 23, 2009
- Committee Members:
- Douglas Henry Werner, Dissertation Advisor/Co-Advisor
Douglas Henry Werner, Committee Chair/Co-Chair
Theresa Stellwag Mayer, Committee Member
Victor P Pasko, Committee Member
Brian Lewis Weiner, Committee Member - Keywords:
- Infrared
Genetic Algorithms
Frequency Selective Surfaces
Metamaterials
Negative Index
Optimization - Abstract:
- Recently, frequency selective surface (FSS) technology that has historically been used in various microwave systems has been adapted to infrared applications by scaling the device dimensions with micro- and nano-fabrication techniques. In addition, FSS technology has been investigated for synthesizing a variety of metamaterials, including artificial magnetic conductors, electromagnetic bandgap structures, metaferrites, and low index metamaterials. However, previous design efforts in the infrared have been limited to using intuitive geometries in the FSS structure. In order to improve the state of the art, genetic algorithm optimization methods incorporating fabrication constraints are introduced in this dissertation that enable the synthesis of infrared FSS with user-defined performance criteria and which are ready for accurate fabrication and characterization using micro- or nanofabrication methods. Synthesis procedures are described and demonstrated for metallodielectric FSS and all-dielectric FSS filters. Additionally, liquid crystal is incorporated into several designs and optimized to have a narrow stop band that is tunable across frequency. Synthesis procedures for realizing negative and zero index metamaterials (NIMs/ZIMs) from single or multi-screen FSS are also introduced in this dissertation. These techniques advance the state of the art by optimizing simultaneously for a desired refractive index, minimum absorption loss, and an impedance match to the surrounding medium. Furthermore, optimizing FSS stacks with many metal layers has revealed that thicker, more practical metamaterials can be realized with low losses and metamaterial properties approaching those of a bulk medium.