Banca de QUALIFICAÇÃO: GABRIEL AMARAL SOUTO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : GABRIEL AMARAL SOUTO
DATE: 28/07/2023
TIME: 09:00
LOCAL: Remoto
TITLE:

Graphene antenna design analysis for Terahertz transmission

KEY WORDS:

Planar Antennas, Graphene, Terahertz Transmission

PAGES: 45
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Telecomunicações
SPECIALTY: Teoria Eletromagnetica, Microondas, Propagação de Ondas, Antenas
SUMMARY:

The constant evolution of information technologies increasingly demands for newer solutions in communication technology for faster and more reliable data transfer. Amidst the emergence of new commercial technologies such as 5G together with other services already established, it is necessary to explore new bandwidth allocations, in this topic, when the operating frequency increases, consequently, the size is reduced for the radiating devices and, for a faster and more reliable transfer rate, in this context, the transmission technology in Terahertz is presented. This work studies the application of graphene antennas as radiant devices in the initial ranges of the Terahertz band (1 to 10 THz) and subterahertz (0 to 1 THz) in laser Quantum Cascade Lasers (QCL), in optical circuit devices. Graphene presents itself as a viable solution to the limitations of metals in terahertz due to its lower loss around the Dirac point and, in addition, it has characteristics such as malleability, adaptability, water resistance and mechanics that make it interesting for certain applications. When propagating photons in cascade, one is generally concerned with the functionality of devices on a micrometer scale, therefore, a cardioid geometry antenna on a silica substrate is proposed as a solution that can be potentially implemented by products already on the market. For the design of this antenna, initially, the conductivity of graphene was calculated through a Drude-like approximation and the Full Wave Method (FWM) was used to find the dimensions where graphene resonates in Terahertz. Then, the Finite Element Method (FEM) was used in commercial software Ansys Electronics Suite HFSS ® to validate the results obtained and it was verified that, for a parametric variation of the height of the substrate, the resonance locus is substantially altered from design. For a simulated center frequency of 2.45 THz, the antenna resonates at 2.59 THz with a bandwidth of 344 GHz with a reflection coefficient of -22.49 dB, with end-fire behavior similar to Vivaldi and slot antennas. For the parametric simulation, heights of 17.5, 22.5, 27.5, 32.5, and 37.5 um were used, it was verified that the designs resonate at 1.87 THz with -14.44 dB of reflection coefficient and 112 GHz of bandwidth. bandwidth, for design with 17.5 um substrate height, 2.11 THz with -18.99 dB reflection coefficient and 132 GHz bandwidth, 2.19 THz with -24.21 dB reflection coefficient reflection with 22.5 um substrate width and 112 GHz bandwidth, 2.93 THz with -31.24 dB reflection coefficient and 112 GHz bandwidth for substrate height of 27.5 um and 4.27 µm THz with -14.44 dB reflection coefficient and 112 GHz bandwidth. Evaluating the bandwidth performance, it is noticed that the simulated device is functional within the proposed application. Future works include the manufacture of an equivalent device to measure the reflection coefficient and evaluate the real viability of a graphene device in Terahertz applications, also, evaluate the behavior of these devices in comparison with noble metals for similar applications, in the same geometry , so that you can have a comparative effect between the two most commonly used solutions for this type of technology.

COMMITTEE MEMBERS:
Interno - 2524053 - ANTONIO LUIZ PEREIRA DE SIQUEIRA CAMPOS
Presidente - 1422265 - JOSE PATROCINIO DA SILVA
Externa à Instituição - SAMANTA MESQUITA DE HOLANDA - UFERSA