Low-loss Dispersion Engineered Wide-band, Multi-band, And Reconfigurable Anisotropic Metamaterials And Bézier Metasurfaces

Open Access
Author:
Sieber, Peter Erich
Graduate Program:
Electrical Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
March 06, 2015
Committee Members:
  • Douglas Henry Werner, Dissertation Advisor
  • Theresa Stellwag Mayer, Committee Member
  • David Carl Swanson, Committee Member
  • Pingjuan Li Werner, Committee Member
Keywords:
  • metamaterials
  • antenna
  • dual band
  • broad band
  • RF switch
  • waveplate
  • metasurface
Abstract:
For more than a decade, metamaterials have generated significant interest due to their theoretical and later experimentally demonstrated properties that are not observed in nature; yet, many of these designs are plagued by very limited bandwidth and/or high losses due to the dispersion characteristics of metamaterials. While many applications exist where a narrow band response is acceptable, examples of dual-band and multi-band responses within a communication bandwidth are limited. Furthermore, the ability to implement reconfigurability becomes complicated due to the lack of high performance switch technologies. In this dissertation, a new technique for constructing and synthesizing broadband metasurfaces is presented. A synthesis technique using Bézier surfaces is subsequently shown to not only outperform known optimization techniques but to produce results with bandwidths far exceeding those found in the literature. Additionally, a composite metamaterial geometry is introduced that facilitates a dual band response with a tunable frequency ratio within usable bands. The design also facilitates reconfigurablity. To mitigate the loss and bandwidth concerns of existing RF switch technologies a new technology is introduced and characterized - a chalcogenide glass phase change material enabled bistable switch. The superior efficiency and bandwidth are subsequently demonstrated by a novel quad state frequency selective surface, which once again boasts multiband reconfigurability within a communication band.