Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure

The research consists of two parts. The first part is the derivation of the design equations for parallel coupled bandpass filter whilst the second part is the modification of the structure to improve the 2nd harmonic rejection. Physical dimension equations by Sina Akhtarzad, Thomas R. Rowbotham and...

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Main Author:	Marimuthu, Jayaseelan
Format:	Thesis
Language:	English
Published:	2004
Subjects:	TK Electrical engineering Electronics Nuclear engineering
Online Access:	http://eprints.utm.my/id/eprint/2962/1/JayaseelanMarimuthuMFKE2004.pdf
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spelling	my-utm-ep.29622018-06-25T00:45:44Z Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure 2004-10 Marimuthu, Jayaseelan TK Electrical engineering. Electronics Nuclear engineering The research consists of two parts. The first part is the derivation of the design equations for parallel coupled bandpass filter whilst the second part is the modification of the structure to improve the 2nd harmonic rejection. Physical dimension equations by Sina Akhtarzad, Thomas R. Rowbotham and Peter B. Johns [18], 1975 were modified to calculate the strip width-to-substrate thickness and like gap-to-substrate thickness ratios from desired values of the even and odd modes characteristic impedances. The modified equations were taken from [12] and [20]. The improved set of equations has accuracy of less than 1.5% and 4% for the even and odd mode characteristic impedances, respectively, compared to [17]. Each length of the coupled region is calculated by using the modified equation of [22]. The designed filter has accuracy of less than 1.64 % and 0.18% for the return and insertion losses, respectively, compared to the design from [17]. Conventional parallel coupled bandpass filter showed very high 2nd harmonic signal at twice the center frequency and asymmetrical response at the upper and lower stop bands. To improve the 2nd harmonic rejection and asymmetrical response at the upper and lower stop bands a modified structure of parallel coupled bandpass filter is proposed. The modified structure is very simple since it does not require recalculation of the physical dimension but showed very good improvement of the 2nd harmonic rejection. The modification was carried out by introducing consecutive square grooves in the arm of the coupled resonator of parallel coupled bandpass filter. The square grooves were placed at equal distance from each other where this ranges from 1 groove up to 7 grooves. The second harmonic present of the in the parallel coupled bandpass filter is due to the different phase velocity experienced by the even and odd modes. For the odd mode, the propagation on in the inner part of the parallel coupled line travels at high phase velocity compared to the even mode which travels at the outer part. By placing the square grooves at the inner part of the parallel coupled, this equalizes the electrical length for the odd and even modes. Hence, the rejection of 2nd harmonic and the improvement in the asymmetrical response were also achieved. The maximum rejection of -100dB for the 2nd harmonic and 30% improvement of the upper cut off frequency have been achieved 2004-10 Thesis http://eprints.utm.my/id/eprint/2962/ http://eprints.utm.my/id/eprint/2962/1/JayaseelanMarimuthuMFKE2004.pdf application/pdf en public masters 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 Marimuthu, Jayaseelan Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure
description	The research consists of two parts. The first part is the derivation of the design equations for parallel coupled bandpass filter whilst the second part is the modification of the structure to improve the 2nd harmonic rejection. Physical dimension equations by Sina Akhtarzad, Thomas R. Rowbotham and Peter B. Johns [18], 1975 were modified to calculate the strip width-to-substrate thickness and like gap-to-substrate thickness ratios from desired values of the even and odd modes characteristic impedances. The modified equations were taken from [12] and [20]. The improved set of equations has accuracy of less than 1.5% and 4% for the even and odd mode characteristic impedances, respectively, compared to [17]. Each length of the coupled region is calculated by using the modified equation of [22]. The designed filter has accuracy of less than 1.64 % and 0.18% for the return and insertion losses, respectively, compared to the design from [17]. Conventional parallel coupled bandpass filter showed very high 2nd harmonic signal at twice the center frequency and asymmetrical response at the upper and lower stop bands. To improve the 2nd harmonic rejection and asymmetrical response at the upper and lower stop bands a modified structure of parallel coupled bandpass filter is proposed. The modified structure is very simple since it does not require recalculation of the physical dimension but showed very good improvement of the 2nd harmonic rejection. The modification was carried out by introducing consecutive square grooves in the arm of the coupled resonator of parallel coupled bandpass filter. The square grooves were placed at equal distance from each other where this ranges from 1 groove up to 7 grooves. The second harmonic present of the in the parallel coupled bandpass filter is due to the different phase velocity experienced by the even and odd modes. For the odd mode, the propagation on in the inner part of the parallel coupled line travels at high phase velocity compared to the even mode which travels at the outer part. By placing the square grooves at the inner part of the parallel coupled, this equalizes the electrical length for the odd and even modes. Hence, the rejection of 2nd harmonic and the improvement in the asymmetrical response were also achieved. The maximum rejection of -100dB for the 2nd harmonic and 30% improvement of the upper cut off frequency have been achieved
format	Thesis
qualification_level	Master's degree
author	Marimuthu, Jayaseelan
author_facet	Marimuthu, Jayaseelan
author_sort	Marimuthu, Jayaseelan
title	Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure
title_short	Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure
title_full	Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure
title_fullStr	Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure
title_full_unstemmed	Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure
title_sort	design of microwave bandpass filter with novel parallel coupled grooved microstrip structure
granting_institution	Universiti Teknologi Malaysia, Faculty of Electrical Engineering
granting_department	Faculty of Electrical Engineering
publishDate	2004
url	http://eprints.utm.my/id/eprint/2962/1/JayaseelanMarimuthuMFKE2004.pdf
_version_	1747814432170311680

Design of microwave bandpass filter with novel parallel coupled grooved microstrip structure

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