Microwave reflectometer for soil moisture and permittivity measurement

Microwave sensors are commonly used for aquametry measurements due to strong tendency of water molecule in absorbing microwave signals. Nowadays, meter-based microwave system is in demand as more applications need concept of being portable and simple. This thesis presents a microwave reflectometer,...

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Main Author:	Then, Yi Lung
Format:	Thesis
Language:	English
Published:	2016
Subjects:	TK Electrical engineering Electronics Nuclear engineering
Online Access:	http://eprints.utm.my/id/eprint/78618/1/ThenYiLungPFKE2016.pdf
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spelling	my-utm-ep.786182018-08-29T07:53:05Z Microwave reflectometer for soil moisture and permittivity measurement 2016-01 Then, Yi Lung TK Electrical engineering. Electronics Nuclear engineering Microwave sensors are commonly used for aquametry measurements due to strong tendency of water molecule in absorbing microwave signals. Nowadays, meter-based microwave system is in demand as more applications need concept of being portable and simple. This thesis presents a microwave reflectometer, which operates between 2.2 GHz and 4.4 GHz. It can measure soil moisture content, m.c. up to 26 % with mean deviation between predicted and actual m.c. determined at ± 2.0 %. Five common soil samples found in southern region of Peninsular Malaysia, Johor were characterized based on macroscopic and microscopic experiments. Throughout the research, four microstrip ring resonantor sensors operating between 2.2 GHz and 4.4 GHz were designed with different angles of microstrip bends. (Conventional Sensor = 0.98 rad., Sensor A = 1.34 rad., Sensor B = 1.57 rad., and Sensor C = 1.64 rad.). Sensor B was chosen as the soil sensor. A critical study on the use of microstrip ring resonator sensors for the determination of both permittivity, er and m.c. from the measured scattering parameters (S-parameters) in conjunction with E5071C vector network analyzer (VNA) was presented. The relationship between the measured er and m.c. obtained from the oven drying method was established. From the results, it was observed that two dielectric relaxation conditions (bound and free water) exist in soil-water mixture. A semi-empirical equivalent lumped element model was created based on simulation data obtained from Microwave Office (AWR) software. The predicted er results from the model agree with the measured data using commercial HP85070D dielectric probe. The model successfully estimated er for the five common soil types with error of 2.5 %. By using inverse algorithm from the model, m.c. was predicted and was in good agreement with the standard oven drying method with its average error within ± 1.5 % for all soil samples. In general, microwave reflectometer with the proposed MRR sensor, provide nondestructive measurement for rapid determination of soil m.c. and er. 2016-01 Thesis http://eprints.utm.my/id/eprint/78618/ http://eprints.utm.my/id/eprint/78618/1/ThenYiLungPFKE2016.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:97492 phd doctoral Universiti Teknologi Malaysia, Faculty of Electrical Engineering Faculty of Electrical Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TK Electrical engineering Electronics Nuclear engineering
spellingShingle	TK Electrical engineering Electronics Nuclear engineering Then, Yi Lung Microwave reflectometer for soil moisture and permittivity measurement
description	Microwave sensors are commonly used for aquametry measurements due to strong tendency of water molecule in absorbing microwave signals. Nowadays, meter-based microwave system is in demand as more applications need concept of being portable and simple. This thesis presents a microwave reflectometer, which operates between 2.2 GHz and 4.4 GHz. It can measure soil moisture content, m.c. up to 26 % with mean deviation between predicted and actual m.c. determined at ± 2.0 %. Five common soil samples found in southern region of Peninsular Malaysia, Johor were characterized based on macroscopic and microscopic experiments. Throughout the research, four microstrip ring resonantor sensors operating between 2.2 GHz and 4.4 GHz were designed with different angles of microstrip bends. (Conventional Sensor = 0.98 rad., Sensor A = 1.34 rad., Sensor B = 1.57 rad., and Sensor C = 1.64 rad.). Sensor B was chosen as the soil sensor. A critical study on the use of microstrip ring resonator sensors for the determination of both permittivity, er and m.c. from the measured scattering parameters (S-parameters) in conjunction with E5071C vector network analyzer (VNA) was presented. The relationship between the measured er and m.c. obtained from the oven drying method was established. From the results, it was observed that two dielectric relaxation conditions (bound and free water) exist in soil-water mixture. A semi-empirical equivalent lumped element model was created based on simulation data obtained from Microwave Office (AWR) software. The predicted er results from the model agree with the measured data using commercial HP85070D dielectric probe. The model successfully estimated er for the five common soil types with error of 2.5 %. By using inverse algorithm from the model, m.c. was predicted and was in good agreement with the standard oven drying method with its average error within ± 1.5 % for all soil samples. In general, microwave reflectometer with the proposed MRR sensor, provide nondestructive measurement for rapid determination of soil m.c. and er.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Then, Yi Lung
author_facet	Then, Yi Lung
author_sort	Then, Yi Lung
title	Microwave reflectometer for soil moisture and permittivity measurement
title_short	Microwave reflectometer for soil moisture and permittivity measurement
title_full	Microwave reflectometer for soil moisture and permittivity measurement
title_fullStr	Microwave reflectometer for soil moisture and permittivity measurement
title_full_unstemmed	Microwave reflectometer for soil moisture and permittivity measurement
title_sort	microwave reflectometer for soil moisture and permittivity measurement
granting_institution	Universiti Teknologi Malaysia, Faculty of Electrical Engineering
granting_department	Faculty of Electrical Engineering
publishDate	2016
url	http://eprints.utm.my/id/eprint/78618/1/ThenYiLungPFKE2016.pdf
_version_	1747818029747535872

Microwave reflectometer for soil moisture and permittivity measurement

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