Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS)

Terahertz (THz) technology has sparked the interest among researchers to explore the terahertz radiation. However, low detection sensitivity has become the main concern in terahertz spectroscopy in which led to discovery of improvement on limited detection sensitivity by using Frequency Selective Su...

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Main Author:	Ishak, Nurul Syafeeqa
Format:	Thesis
Language:	English English English
Published:	2022
Subjects:	TA Engineering (General) Civil engineering (General)
Online Access:	http://eprints.uthm.edu.my/8468/1/24p%20NURUL%20SYAFEEQA%20ISHAK.pdf http://eprints.uthm.edu.my/8468/2/NURUL%20SYAFEEQA%20ISHAK%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/8468/3/NURUL%20SYAFEEQA%20ISHAK%20WATERMARK.pdf
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spelling	my-uthm-ep.84682023-03-01T06:58:54Z Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS) 2022-04 Ishak, Nurul Syafeeqa TA Engineering (General). Civil engineering (General) Terahertz (THz) technology has sparked the interest among researchers to explore the terahertz radiation. However, low detection sensitivity has become the main concern in terahertz spectroscopy in which led to discovery of improvement on limited detection sensitivity by using Frequency Selective Surface (FSS) that provided by the high electric-field concentration in the spatial filtering in FSS. Parametric studies on FSS slot structures, of circular, square, and ring, were explored using CST MICROWAVE STUDIO® software to observe the feasibility of the FSS structures and characterise their performance based on their physical dimensions. Circular slot FSS on the surface of the RT/Duroid® 5880LZ board with thickness of 508 μm showed acceptable results in simulation and measurement despite the limitations of the PCB fabrication. Based on the parametric study of all structures, through surface current intensity on the surface of FSS with or without the FSS showed increase by 20% when the FSS was applied. Next, circular slot FSS was optimised with the utilisation of FSS in material sensing applications towards the molecular resonance of glucose, fructose, and sucrose at THz range resulting the observation at 1.10 THz and 1.98 THz for glucose, 1.29 THz and 1.67 THz for fructose and 1.31 THz and 1.80 THz for sucrose. In this research, electron-beam lithography and chemical etching were used in the microfabrication of FSS on quartz substrate with an aluminium layer due to the limitation of PCB fabrication at THz range and the suitability of microfabrication. Comparing the simulation and measured results of the FSS samples, FSS1 had fair shifts in transmission magnitude by approximately 30% compared with FSS2, which had 50% shifts in transmission magnitude. The focus of this study was to improve the detection sensitivity of terahertz spectroscopy by using FSS for sensing at low concentrations. Therefore, when cascading FSS with the sugar samples, the detection sensitivity at the terahertz range increased by 25% for glucose at 1.98 THz, by 28% for fructose at 1.67 THz, and by 13% for sucrose at 1.80 THz. 2022-04 Thesis http://eprints.uthm.edu.my/8468/ http://eprints.uthm.edu.my/8468/1/24p%20NURUL%20SYAFEEQA%20ISHAK.pdf text en public http://eprints.uthm.edu.my/8468/2/NURUL%20SYAFEEQA%20ISHAK%20COPYRIGHT%20DECLARATION.pdf text en staffonly http://eprints.uthm.edu.my/8468/3/NURUL%20SYAFEEQA%20ISHAK%20WATERMARK.pdf text en validuser phd doctoral Universiti Tun Hussein Onn Malaysia Fakulti Kejuruteraan Elektrik dan Elektronik
institution	Universiti Tun Hussein Onn Malaysia
collection	UTHM Institutional Repository
language	English English English
topic	TA Engineering (General) Civil engineering (General)
spellingShingle	TA Engineering (General) Civil engineering (General) Ishak, Nurul Syafeeqa Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS)
description	Terahertz (THz) technology has sparked the interest among researchers to explore the terahertz radiation. However, low detection sensitivity has become the main concern in terahertz spectroscopy in which led to discovery of improvement on limited detection sensitivity by using Frequency Selective Surface (FSS) that provided by the high electric-field concentration in the spatial filtering in FSS. Parametric studies on FSS slot structures, of circular, square, and ring, were explored using CST MICROWAVE STUDIO® software to observe the feasibility of the FSS structures and characterise their performance based on their physical dimensions. Circular slot FSS on the surface of the RT/Duroid® 5880LZ board with thickness of 508 μm showed acceptable results in simulation and measurement despite the limitations of the PCB fabrication. Based on the parametric study of all structures, through surface current intensity on the surface of FSS with or without the FSS showed increase by 20% when the FSS was applied. Next, circular slot FSS was optimised with the utilisation of FSS in material sensing applications towards the molecular resonance of glucose, fructose, and sucrose at THz range resulting the observation at 1.10 THz and 1.98 THz for glucose, 1.29 THz and 1.67 THz for fructose and 1.31 THz and 1.80 THz for sucrose. In this research, electron-beam lithography and chemical etching were used in the microfabrication of FSS on quartz substrate with an aluminium layer due to the limitation of PCB fabrication at THz range and the suitability of microfabrication. Comparing the simulation and measured results of the FSS samples, FSS1 had fair shifts in transmission magnitude by approximately 30% compared with FSS2, which had 50% shifts in transmission magnitude. The focus of this study was to improve the detection sensitivity of terahertz spectroscopy by using FSS for sensing at low concentrations. Therefore, when cascading FSS with the sugar samples, the detection sensitivity at the terahertz range increased by 25% for glucose at 1.98 THz, by 28% for fructose at 1.67 THz, and by 13% for sucrose at 1.80 THz.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Ishak, Nurul Syafeeqa
author_facet	Ishak, Nurul Syafeeqa
author_sort	Ishak, Nurul Syafeeqa
title	Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS)
title_short	Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS)
title_full	Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS)
title_fullStr	Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS)
title_full_unstemmed	Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS)
title_sort	detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (fss)
granting_institution	Universiti Tun Hussein Onn Malaysia
granting_department	Fakulti Kejuruteraan Elektrik dan Elektronik
publishDate	2022
url	http://eprints.uthm.edu.my/8468/1/24p%20NURUL%20SYAFEEQA%20ISHAK.pdf http://eprints.uthm.edu.my/8468/2/NURUL%20SYAFEEQA%20ISHAK%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/8468/3/NURUL%20SYAFEEQA%20ISHAK%20WATERMARK.pdf
_version_	1776103352997773312

Detection of sugar solution at low concentration using terahertz spectroscopy combined with frequency-selective surface (FSS)

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