A New Class of High-Selectivity Bandpass Filters With Constant Bandwidth and 5:1 Bandwidth Tuning Ratio

This paper presents a design for compact bandpass filters (BPFs) that feature high selectivity. This high selectivity is achieved through the use of open-/short-circuited coupled-line segments at the filter’s input and output and a pair of symmetrical parallel-coupled lines connected to a...

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Main Authors: Photos Vryonides, Salman Arain, Abdul Quddious, Dimitra Psychogiou, Symeon Nikolaou
Format: Article
Language:English
Published: IEEE 2024-01-01
Series:IEEE Access
Subjects:
Online Access:https://ieeexplore.ieee.org/document/10417067/
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author Photos Vryonides
Salman Arain
Abdul Quddious
Dimitra Psychogiou
Symeon Nikolaou
author_facet Photos Vryonides
Salman Arain
Abdul Quddious
Dimitra Psychogiou
Symeon Nikolaou
author_sort Photos Vryonides
collection DOAJ
description This paper presents a design for compact bandpass filters (BPFs) that feature high selectivity. This high selectivity is achieved through the use of open-/short-circuited coupled-line segments at the filter&#x2019;s input and output and a pair of symmetrical parallel-coupled lines connected to a pair of open stepped-impedance resonators (SIRs) introducing three transmission zeros (TZs) on either side of the passband. In addition, two different designs for these BPFs, one with a fixed bandwidth and one with a tunable bandwidth are also presented. The characteristics of the proposed structure are analyzed using even-, odd-mode and ABCD analyses. To enable bandwidth tuning, two varactor diodes are added to the edges of the open SIRs, allowing the TZs to be adjusted around the upper band edge. The paper includes details of two prototypes that were designed, fabricated, and tested: Filter A with a constant bandwidth that covers the entire S-band (2-4 GHz) and a 3-dB fractional bandwidth (FBW) of 60&#x0025;, and Filter B with a tunable bandwidth and a 3-dB FBW that varies from 12&#x0025; to 60&#x0025;. The filters have been measured to have insertion loss of less than 0.8 dB for Filter A and less than 1.1 dB for Filter B throughout the passband, and return loss of greater than 16 dB and 15 dB for Filter A and B, respectively. These filters have a compact size of less than <inline-formula> <tex-math notation="LaTeX">$0.113\lambda _{g}^{2}$ </tex-math></inline-formula>, and feature high selectivity with a wide 3-dB bandwidth tuning range ratio, as well as an upper stopband suppression level of more than 40 dB.
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spelling doaj.art-3252e9f50d6b4614a8b51812c8d5533c2024-02-06T00:01:17ZengIEEEIEEE Access2169-35362024-01-0112164891649710.1109/ACCESS.2024.335867710417067A New Class of High-Selectivity Bandpass Filters With Constant Bandwidth and 5:1 Bandwidth Tuning RatioPhotos Vryonides0https://orcid.org/0000-0002-2625-2383Salman Arain1Abdul Quddious2https://orcid.org/0000-0002-7417-4068Dimitra Psychogiou3https://orcid.org/0000-0003-1936-4026Symeon Nikolaou4https://orcid.org/0000-0002-9234-9415Department of Electrical and Computer Engineering and Informatics, Frederick University, Nicosia, CyprusElectrical Engineering Department, NFC Institute of Engineering and Fertilizer Research, Faisalabad, PakistanChair for RF and Photonics Engineering, Technische Universit&#x00E4;t Dresden, Dresden, GermanySchool of Engineering, University College Cork, Cork 021, IrelandDepartment of Electrical and Computer Engineering and Informatics, Frederick University, Nicosia, CyprusThis paper presents a design for compact bandpass filters (BPFs) that feature high selectivity. This high selectivity is achieved through the use of open-/short-circuited coupled-line segments at the filter&#x2019;s input and output and a pair of symmetrical parallel-coupled lines connected to a pair of open stepped-impedance resonators (SIRs) introducing three transmission zeros (TZs) on either side of the passband. In addition, two different designs for these BPFs, one with a fixed bandwidth and one with a tunable bandwidth are also presented. The characteristics of the proposed structure are analyzed using even-, odd-mode and ABCD analyses. To enable bandwidth tuning, two varactor diodes are added to the edges of the open SIRs, allowing the TZs to be adjusted around the upper band edge. The paper includes details of two prototypes that were designed, fabricated, and tested: Filter A with a constant bandwidth that covers the entire S-band (2-4 GHz) and a 3-dB fractional bandwidth (FBW) of 60&#x0025;, and Filter B with a tunable bandwidth and a 3-dB FBW that varies from 12&#x0025; to 60&#x0025;. The filters have been measured to have insertion loss of less than 0.8 dB for Filter A and less than 1.1 dB for Filter B throughout the passband, and return loss of greater than 16 dB and 15 dB for Filter A and B, respectively. These filters have a compact size of less than <inline-formula> <tex-math notation="LaTeX">$0.113\lambda _{g}^{2}$ </tex-math></inline-formula>, and feature high selectivity with a wide 3-dB bandwidth tuning range ratio, as well as an upper stopband suppression level of more than 40 dB.https://ieeexplore.ieee.org/document/10417067/Bandpass filter (BPF)parallel-coupled linesselectivitytransmission zeros (TZs)
spellingShingle Photos Vryonides
Salman Arain
Abdul Quddious
Dimitra Psychogiou
Symeon Nikolaou
A New Class of High-Selectivity Bandpass Filters With Constant Bandwidth and 5:1 Bandwidth Tuning Ratio
IEEE Access
Bandpass filter (BPF)
parallel-coupled lines
selectivity
transmission zeros (TZs)
title A New Class of High-Selectivity Bandpass Filters With Constant Bandwidth and 5:1 Bandwidth Tuning Ratio
title_full A New Class of High-Selectivity Bandpass Filters With Constant Bandwidth and 5:1 Bandwidth Tuning Ratio
title_fullStr A New Class of High-Selectivity Bandpass Filters With Constant Bandwidth and 5:1 Bandwidth Tuning Ratio
title_full_unstemmed A New Class of High-Selectivity Bandpass Filters With Constant Bandwidth and 5:1 Bandwidth Tuning Ratio
title_short A New Class of High-Selectivity Bandpass Filters With Constant Bandwidth and 5:1 Bandwidth Tuning Ratio
title_sort new class of high selectivity bandpass filters with constant bandwidth and 5 1 bandwidth tuning ratio
topic Bandpass filter (BPF)
parallel-coupled lines
selectivity
transmission zeros (TZs)
url https://ieeexplore.ieee.org/document/10417067/
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