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Achieving subwavelength field confinement in sub-terahertz regime by periodic metallodielectric waveguides

Tehranian, A ; Sharif University of Technology | 2019

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  1. Type of Document: Article
  2. DOI: 10.1364/OE.27.004226
  3. Publisher: OSA - The Optical Society , 2019
  4. Abstract:
  5. In this paper, we report on a periodic metallo-dielectric structure that supports geometry-induced surface plasmons in the sub-terahertz regime. The proposed structure is made up of a dielectric-coated metallic grating sandwiched by parallel metal plates. Based on the modal analysis of 2D and 3D structures, the impact of a metal cladding and a customized dielectric coating on the dispersion relation and field distribution of the guided surface wave is investigated. It is found that modal field confinement is improved in the presence of a metal cladding without narrowing the operational bandwidth of the waveguide. Moreover, a customized subwavelength-sized dielectric coating based on high-resistivity silicon (HR-Si) can further improve the confinement. As a result, by incorporating both the HR-Si coating and the metal cladding in a conventional metallic grating, subwavelength field confinement is achieved over nearly a 2:1 frequency bandwidth. The achieved performance makes the realization of extremely-low radiation loss sharp bends possible. In particular, the achieved radiation loss is less than 0.5dB for a 90° bend of radius λ 0 /4 based on a waveguide crosssectional dimension of almost λ 0 /10 where λ 0 is the free-space wavelength at the maximum frequency of operation. The proposed waveguide is promising for the implementation of subterahertz guided-wave devices and circuits thanks to its outstanding field confinement and ruggedized and shielded structure. © 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
  6. Keywords:
  7. Bandwidth ; Coatings ; Diffraction gratings ; Guided electromagnetic wave propagation ; Metal cladding ; Modal analysis ; Surface plasmons ; Surface waves ; Waveguides ; Dispersion relations ; Free-space wavelengths ; Frequency band width ; Guided surface waves ; High resistivity silicon ; Metallodielectric waveguides ; Operational bandwidth ; Parallel metal plates ; Metals
  8. Source: Optics Express ; Volume 27, Issue 4 , 2019 , Pages 4226-4237 ; 10944087 (ISSN)
  9. URL: https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-27-4-4226&id=404704