Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors

Conductor-backed coplanar waveguide (CBCWG)l moisture sensor has been developed for a quick and accurate determination of moisture content in fresh mesocarp of the oil palm ftuits and cocoa beans. The sensor consists of three parts i.e, the coupling system representing the 1ranSition between coa...

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Main Author:	Teoh, Lay Hua
Format:	Thesis
Language:	English English
Published:	1997
Subjects:	Wave guides - Case studies Microwave filters
Online Access:	http://psasir.upm.edu.my/id/eprint/8633/1/FSAS_1997_18_A.pdf
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id	my-upm-ir.8633
record_format	uketd_dc
spelling	my-upm-ir.86332012-05-08T09:12:18Z Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors 1997 Teoh, Lay Hua Conductor-backed coplanar waveguide (CBCWG)l moisture sensor has been developed for a quick and accurate determination of moisture content in fresh mesocarp of the oil palm ftuits and cocoa beans. The sensor consists of three parts i.e, the coupling system representing the 1ranSition between coaxia11ine to the CBCWG, the 2-layer structure of the CBCWG and sensing area. Previous wade done shows a close relationship between the oil content and moisture content in the oil palm mesocarp during fruit development The quality of cocoa beaus were also affected by the moisture content in the beans. Thus, by measuring the moisture content in the oil pahn mesocarp and cocoa beans, the quality of the oil palm fruit and the cocoa beans can be obtained indirectly. A functional relationship has been developed between scattering parameter 821 of the sensor and moisture content of the sample. The reflection and transmission phenomena in the sensor structure can be represented by a signal flow graph and can be simplified by using Mason's non-touching loop roles. The calculation of S21 is based on the quasi-transverse electtomagnetic mode approxima1ion. Based on the theoretical analysis, computer programmes written in FORTRAN programming language were developed to do the calculations of the attenuation. A total of four different sensors were developed in order to find out the effect of different gap between the conducting S1rip and upper ground plane and protective layers on the attenuation values. It is found that the big gap sensor gives a better sensitivity as compared to the small gap sensor. This effect is probably due to the field density in the big gap sensor is much higher than the small gap sensor. The sensitivity of the sensor is also drastically affected by the thickness of the protective layer. This is due to the decreasing of the interaction between the field and the sample as the thickness of the protective layer increases. A comparison between the theoretical and experimental results for the oil palm mesocatp was done. A close agreement has been found. The difference in value ranges from only 1-4dB. The fine relationship between the attenuation and moisture content for this kind of sensor gives the possibility for the development of a compact and portable microwave instrument for assessing the quality of cocoa and oil palm fruits that are sent to the factory. Wave guides - Case studies Microwave filters 1997 Thesis http://psasir.upm.edu.my/id/eprint/8633/ http://psasir.upm.edu.my/id/eprint/8633/1/FSAS_1997_18_A.pdf application/pdf en public masters Universiti Putra Malaysia Wave guides - Case studies Microwave filters Faculty of Environmental Studies English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
topic	Wave guides - Case studies Microwave filters
spellingShingle	Wave guides - Case studies Microwave filters Teoh, Lay Hua Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors
description	Conductor-backed coplanar waveguide (CBCWG)l moisture sensor has been developed for a quick and accurate determination of moisture content in fresh mesocarp of the oil palm ftuits and cocoa beans. The sensor consists of three parts i.e, the coupling system representing the 1ranSition between coaxia11ine to the CBCWG, the 2-layer structure of the CBCWG and sensing area. Previous wade done shows a close relationship between the oil content and moisture content in the oil palm mesocarp during fruit development The quality of cocoa beaus were also affected by the moisture content in the beans. Thus, by measuring the moisture content in the oil pahn mesocarp and cocoa beans, the quality of the oil palm fruit and the cocoa beans can be obtained indirectly. A functional relationship has been developed between scattering parameter 821 of the sensor and moisture content of the sample. The reflection and transmission phenomena in the sensor structure can be represented by a signal flow graph and can be simplified by using Mason's non-touching loop roles. The calculation of S21 is based on the quasi-transverse electtomagnetic mode approxima1ion. Based on the theoretical analysis, computer programmes written in FORTRAN programming language were developed to do the calculations of the attenuation. A total of four different sensors were developed in order to find out the effect of different gap between the conducting S1rip and upper ground plane and protective layers on the attenuation values. It is found that the big gap sensor gives a better sensitivity as compared to the small gap sensor. This effect is probably due to the field density in the big gap sensor is much higher than the small gap sensor. The sensitivity of the sensor is also drastically affected by the thickness of the protective layer. This is due to the decreasing of the interaction between the field and the sample as the thickness of the protective layer increases. A comparison between the theoretical and experimental results for the oil palm mesocatp was done. A close agreement has been found. The difference in value ranges from only 1-4dB. The fine relationship between the attenuation and moisture content for this kind of sensor gives the possibility for the development of a compact and portable microwave instrument for assessing the quality of cocoa and oil palm fruits that are sent to the factory.
format	Thesis
qualification_level	Master's degree
author	Teoh, Lay Hua
author_facet	Teoh, Lay Hua
author_sort	Teoh, Lay Hua
title	Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors
title_short	Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors
title_full	Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors
title_fullStr	Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors
title_full_unstemmed	Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors
title_sort	development of conductor-backed coplanar waveguide (cbcwg) moisture sensors
granting_institution	Universiti Putra Malaysia
granting_department	Faculty of Environmental Studies
publishDate	1997
url	http://psasir.upm.edu.my/id/eprint/8633/1/FSAS_1997_18_A.pdf
_version_	1747810844087943168

Development of Conductor-Backed Coplanar Waveguide (CBCWG) Moisture Sensors

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