Design of switchable mathed bandstop filter

New developments in the design of band reject filters are essential to meet the ever increasing demands on suppression of unwanted signals and miniaturization of microwave communications systems. A compact design can be achieved through the implementation of planar microstrip technology. Conventiona...

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Main Author: Zahari, Mohd Khairy
Format: Thesis
Language:English
English
Published: 2013
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spelling my-utem-ep.149852022-09-20T12:11:10Z Design of switchable mathed bandstop filter 2013 Zahari, Mohd Khairy T Technology (General) TK Electrical engineering. Electronics Nuclear engineering New developments in the design of band reject filters are essential to meet the ever increasing demands on suppression of unwanted signals and miniaturization of microwave communications systems. A compact design can be achieved through the implementation of planar microstrip technology. Conventional electronically tunable bandstop filters suffer performance degradation due to the finite unloaded Q of the resonators and also the loss associated with the switching elements. Recently a new filter topology using lossy resonators has been introduced where the topology can be used to partially compensate for the loss. A frequency agile bandstop filter based on this topology has been developed, but such filters as well as conventional switchable bandstop filters encounter performance degradation in terms of tuning bandwidth and stopband bandwidth due to the frequency dependant losses and couplings. Through this thesis the filter is designed and developed an L-shape matched bandstop filter and dual mode ring resonator which can be switchable based on a lossy allpass network. The filters are integrated with switching elements that suitable for the perfectly matched bandstop concept. The lossy allpass network demonstrates the concept and design of perfectly matched bandstop response with a perfectly matched at all frequencies. The filter is based on the half-wavelength λ/2 resonator with gap coupling, parallel with an allpass nominally-90°-phase-shift element, which can be optimized to achieve high Q-factor. The switchable L-shape matched bandstop filter and switchable dual mode ring resonator can be realized by using PIN diodes as a switching elements. The dual-mode ring resonator structure is composed by two degenerate modes or splitting resonant frequencies. Two degenerate modes can be excited by perturbing stubs, notches or symmetrical feed lines. The dual-mode ring resonator stub’s is located at 135°. Both filters provide two state of operation under two conditions. The first condition is that the filter will produce allpass response when the PIN diodes are turned ‘ON’. The second condition is that the filter will produce perfectly matched bandstop response when the PIN diodes are turned ‘OFF’. The perfectly matched bandstop filter operates 1 GHz where S11 and S21 having the same attenuation at 1 GHz. For S11 must be less than 15 dB and S21 the attenuation level less than 15 dB. The allpass response having S21 ≈0.2 dB. 2013 Thesis http://eprints.utem.edu.my/id/eprint/14985/ http://eprints.utem.edu.my/id/eprint/14985/1/Design%20Of%20Switchable%20Matched%20bandstop%20Filter%2024pages.pdf text en public http://eprints.utem.edu.my/id/eprint/14985/2/Design%20of%20switchable%20matched%20bandstop%20filter.pdf text en validuser https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=92083 mphil masters Universiti Teknikal Malaysia Melaka Faculty of Electronic and Computer Engineering
institution Universiti Teknikal Malaysia Melaka
collection UTeM Repository
language English
English
topic T Technology (General)
T Technology (General)
spellingShingle T Technology (General)
T Technology (General)
Zahari, Mohd Khairy
Design of switchable mathed bandstop filter
description New developments in the design of band reject filters are essential to meet the ever increasing demands on suppression of unwanted signals and miniaturization of microwave communications systems. A compact design can be achieved through the implementation of planar microstrip technology. Conventional electronically tunable bandstop filters suffer performance degradation due to the finite unloaded Q of the resonators and also the loss associated with the switching elements. Recently a new filter topology using lossy resonators has been introduced where the topology can be used to partially compensate for the loss. A frequency agile bandstop filter based on this topology has been developed, but such filters as well as conventional switchable bandstop filters encounter performance degradation in terms of tuning bandwidth and stopband bandwidth due to the frequency dependant losses and couplings. Through this thesis the filter is designed and developed an L-shape matched bandstop filter and dual mode ring resonator which can be switchable based on a lossy allpass network. The filters are integrated with switching elements that suitable for the perfectly matched bandstop concept. The lossy allpass network demonstrates the concept and design of perfectly matched bandstop response with a perfectly matched at all frequencies. The filter is based on the half-wavelength λ/2 resonator with gap coupling, parallel with an allpass nominally-90°-phase-shift element, which can be optimized to achieve high Q-factor. The switchable L-shape matched bandstop filter and switchable dual mode ring resonator can be realized by using PIN diodes as a switching elements. The dual-mode ring resonator structure is composed by two degenerate modes or splitting resonant frequencies. Two degenerate modes can be excited by perturbing stubs, notches or symmetrical feed lines. The dual-mode ring resonator stub’s is located at 135°. Both filters provide two state of operation under two conditions. The first condition is that the filter will produce allpass response when the PIN diodes are turned ‘ON’. The second condition is that the filter will produce perfectly matched bandstop response when the PIN diodes are turned ‘OFF’. The perfectly matched bandstop filter operates 1 GHz where S11 and S21 having the same attenuation at 1 GHz. For S11 must be less than 15 dB and S21 the attenuation level less than 15 dB. The allpass response having S21 ≈0.2 dB.
format Thesis
qualification_name Master of Philosophy (M.Phil.)
qualification_level Master's degree
author Zahari, Mohd Khairy
author_facet Zahari, Mohd Khairy
author_sort Zahari, Mohd Khairy
title Design of switchable mathed bandstop filter
title_short Design of switchable mathed bandstop filter
title_full Design of switchable mathed bandstop filter
title_fullStr Design of switchable mathed bandstop filter
title_full_unstemmed Design of switchable mathed bandstop filter
title_sort design of switchable mathed bandstop filter
granting_institution Universiti Teknikal Malaysia Melaka
granting_department Faculty of Electronic and Computer Engineering
publishDate 2013
url http://eprints.utem.edu.my/id/eprint/14985/1/Design%20Of%20Switchable%20Matched%20bandstop%20Filter%2024pages.pdf
http://eprints.utem.edu.my/id/eprint/14985/2/Design%20of%20switchable%20matched%20bandstop%20filter.pdf
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