Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits

The thesis describes the development of a low cost open-ended coaxial sensor for the determination of both complex permittivity and moisture content of the oil palm fruits of various degree of fruit ripeness. The sensor operating between 2 GHz and 4 GHz was fabricated from an inexpensive 4.1 mm o...

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Main Author:	You, Kok Yeow
Format:	Thesis
Language:	English English
Published:	2003
Subjects:	Dielectric measurements Fruit - Ripening
Online Access:	http://psasir.upm.edu.my/id/eprint/9537/1/FSAS_2003_6_A.pdf
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spelling	my-upm-ir.95372012-05-21T01:28:39Z Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits 2003-04 You, Kok Yeow The thesis describes the development of a low cost open-ended coaxial sensor for the determination of both complex permittivity and moisture content of the oil palm fruits of various degree of fruit ripeness. The sensor operating between 2 GHz and 4 GHz was fabricated from an inexpensive 4.1 mm outer diameter SMA coaxial stub contact panel and suitable for single fruit measurement. A theoretical analysis has been carried out to establish the optimum operating frequency based on the relation ship between the admittance and frequency of the sensor. The propagation of electromagnetic wave is assumed to be transverse electromagnetic (TEM) mode. The measurement system consists of the sensor and a PC-controlled vector network analyzer (VNA). A dielectric measurement software has been developed to control and acquire data from the VNA using Agilent VEE. The software is also used to calculate the complex permittivity from the measured reflection coefficient at each 201 frequency points between 2 GHz and 4 GHz. The permittivity values were then fitted to a dielectric mixture model to obtain the values of moisture content of oil palm fruits. The actual moisture content were found by standard oven drying method. A calibration equation relating the measured and predicted moisture content has been established based on more than 80 fruit samples. The equation was found to be accurate within 5.2 ± 0.4 % when tested on 69 different fruit samples. The values of moisture content obtained from the calibration equation were used in the mixture model to improve accuracy in the determination of the complex permittivity of the oil palm fruits. The sensitivities of the sensor in the measurement of the dielectric constant and loss factor of the oil palm fruits with respect to changes in moisture content were typically 0.82 and 0.05, respectively. The sensor can be used to monitor fruit ripeness based on the measurement of the magnitude of reflection coefficient alone. Fruits are considered to reach ripeness stage once the magnitude of the reflection coefficient is greater than 0.85 at optimum operating frequency 2.6 GHz. Dielectric measurements Fruit - Ripening 2003-04 Thesis http://psasir.upm.edu.my/id/eprint/9537/ http://psasir.upm.edu.my/id/eprint/9537/1/FSAS_2003_6_A.pdf application/pdf en public masters Universiti Putra Malaysia Dielectric measurements Fruit - Ripening Faculty of Science and Environmental Studies English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
topic	Dielectric measurements Fruit - Ripening
spellingShingle	Dielectric measurements Fruit - Ripening You, Kok Yeow Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits
description	The thesis describes the development of a low cost open-ended coaxial sensor for the determination of both complex permittivity and moisture content of the oil palm fruits of various degree of fruit ripeness. The sensor operating between 2 GHz and 4 GHz was fabricated from an inexpensive 4.1 mm outer diameter SMA coaxial stub contact panel and suitable for single fruit measurement. A theoretical analysis has been carried out to establish the optimum operating frequency based on the relation ship between the admittance and frequency of the sensor. The propagation of electromagnetic wave is assumed to be transverse electromagnetic (TEM) mode. The measurement system consists of the sensor and a PC-controlled vector network analyzer (VNA). A dielectric measurement software has been developed to control and acquire data from the VNA using Agilent VEE. The software is also used to calculate the complex permittivity from the measured reflection coefficient at each 201 frequency points between 2 GHz and 4 GHz. The permittivity values were then fitted to a dielectric mixture model to obtain the values of moisture content of oil palm fruits. The actual moisture content were found by standard oven drying method. A calibration equation relating the measured and predicted moisture content has been established based on more than 80 fruit samples. The equation was found to be accurate within 5.2 ± 0.4 % when tested on 69 different fruit samples. The values of moisture content obtained from the calibration equation were used in the mixture model to improve accuracy in the determination of the complex permittivity of the oil palm fruits. The sensitivities of the sensor in the measurement of the dielectric constant and loss factor of the oil palm fruits with respect to changes in moisture content were typically 0.82 and 0.05, respectively. The sensor can be used to monitor fruit ripeness based on the measurement of the magnitude of reflection coefficient alone. Fruits are considered to reach ripeness stage once the magnitude of the reflection coefficient is greater than 0.85 at optimum operating frequency 2.6 GHz.
format	Thesis
qualification_level	Master's degree
author	You, Kok Yeow
author_facet	You, Kok Yeow
author_sort	You, Kok Yeow
title	Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits
title_short	Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits
title_full	Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits
title_fullStr	Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits
title_full_unstemmed	Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits
title_sort	development of a new technique for measurement of dielectric properties of oil palm fruits
granting_institution	Universiti Putra Malaysia
granting_department	Faculty of Science and Environmental Studies
publishDate	2003
url	http://psasir.upm.edu.my/id/eprint/9537/1/FSAS_2003_6_A.pdf
_version_	1747810976389922816

Development of a New Technique for Measurement of Dielectric Properties of Oil Palm Fruits

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