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Design, Simulation and Fabrication of Thz Absorber for Thermal Superconducting Detector

Zeynab, Alipour Gougeh | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52296 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Fardmanesh, Mehdi
  7. Abstract:
  8. At almost all frequencies, we have good methods to generate and detect electromagnetic radiations. One crucial exception is the low terahertz range,where despite intensive research there is a severe lack of proper devices for many applications in this frequency range such as oscillators and detectors that is so-called THz gap and includes 0.3 to 10 THz spectrum. There are different types of THz detectors but bandwidth of dection of most of them is narrow. Among these detectors, superconducting transition edge balometer detector has detectivity in wide frequency range. But generally, detectivity of these detectors strongly depends on their ability to absorb radiations of electromagnetic waves incident on them,and their low absorptivity provides a challenge. Metamaterials based absorbers offer an opportunity for increasing the system detectivity by enhancing the total absorbed terahertz radiation incident on the balometers. In this thesis a design and fabrication of wide-band metamaterial absorber for THz detection application is proposed. In this thesis the theories, properties, and applications of metamaterials and THz absorbers are investigated. The intended absorber structures are designed and different parameters of structure like pattern size, thickness of different layers and material type, and their effects on resonant frequency, bandwidth and peak of absoption are discussed and simulated; Specially effects of permeability and conductivity of materials on the absoption are investigated. Different optimized designs, including narrow-band and wide-band absorbers for different frequency ranges, are then proposed. Furthermore, a novel absorber is proposed, where a nearly perfect absorption is gained with a wide-band absorption response of more than 80%, covering a wide frequency range, from 0.4 to 2 THz. Also, a THz absorber with bandwidth of 10 THz (from 1.6 to 10.6 THz) is achived. Fabrication process and some of its challenges for the proposed absorbers are also discussed. Finally characterization and measurement results of a designed and fabricated absorber are presented and compared with the simulation results
  9. Keywords:
  10. Terahertz Absorber ; Terahertz Gap ; Metamaterial Absorbers ; Wide-band Absorber ; Terahertz Detection ; Terahertz Band

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