Terahetz bölgesinde tek katmanlı, yüksek verimli ve geniş band polarizasyon dönüştürücü tasarımı

FATİH KADİROĞLU

Terahetz bölgesinde tek katmanlı, yüksek verimli ve geniş band polarizasyon dönüştürücü tasarımı

Thesis Type: Postgraduate

Institution Of The Thesis: Ataturk University, Fen Bilimleri Enstitüsü, Elektrik Elektronik Mühendisliği Anabilim Dalı, Turkey

Approval Date: 2024

Thesis Language: Turkish

Student: FATİH KADİROĞLU

Supervisor: Gökhan Öztürk

Open Archive Collection: AVESIS Open Access Collection

Abstract:

Purpose: The aim of this study is to design an adaptable, high-efficiency and broadband polarization converter in the terahetz region in a computer environment. Method: In this study, the polarization converter metamaterial is designed with CST Microwave Studio, an electromagnetic simulation program. Current density at resonant frequencies, reflection coefficients for the polarization converter, polarization conversion ratios, orthogonal components and phase differences were simulated with CST Microwave Studio. The dielectric constant of vanadium dioxide is compared with the Bruggeman effective and Drude model. Findings: The designed metamaterial has a polarization conversion rate (PCR) of over 90% in the range of 5.29-13.68 THz, relative bandwidth (RBW) of 88.40%, and PCR value of at least 96% in the range of 5.46-13.62 THz by taking the dielectric constant of vanadium dioxide 9 with the Bruggeman effective model. At the same time, by taking the dielectric constant of vanadium dioxide as 12 with the designed metamaterial Drude model, PCR over 90% in the range of 5.20-13.61 THz, RBW 89.39%, PCR value at least 96% in the range of 5.35-9.62 THz and 10.47-12.64 THz were calculated. Conclusion: In this thesis study, an adaptable, high-efficiency model with a polarization conversion of over 90% and a thickness of 5.4 μm was created with a bandwidth of approximately 8.38 THz when the dielectric constant of Vanadium dioxide was taken as 9 with the Bruggeman effect model, and approximately 8.41 THz when the dielectric constant of Vanadium dioxide was taken as 12 with the Drude model. A dynamic metamaterial was designed because the conductivity level of vanadium dioxide changes according to temperature. Keywords: microwave, polarization converter, vanadium dioxide, metamaterial, PCR, RBW, broadband, terahertz.