Compact dual-band bandstop filter based on coupled open-ended Hilbert resonators

ABSTRACT

In this paper, the design procedure of a compact dual-band bandstop filter (DBBSF) based on coupled open-ended Hilbert lines is proposed. The proposed filter topology consists of two pairs of coupled open-ended lines bended in the shape of the Hilbert fractal curves and a stepped-impedance line section (SIS). In that manner, tree transmission paths are crated allowing the independent control of filter characteristic in both bands. To obtain appropriate coupling between resonators, and the independent control of the center frequencies and in-band characteristics of the filter, the SIS is introduced as matching section. Design rules are derived using lossless transmission line model and even/odd analysis. To validate the design concept, two compact DBBSFs have been designed, fabricated, and measured. The proposed filters exhibit excellent in-band characteristics, high selectivity, and small dimensions.

KEYWORDS:

• Bandstop filter
• dual-band filter
• microstrip
• even/odd analysis
• stepped-impedance

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Vasa Radonić  http://orcid.org/0000-0001-5286-6680

Slobodan Birgermajer  http://orcid.org/0000-0002-0117-8498

Norbert Cselyuszka  http://orcid.org/0000-0003-0027-4207

Vesna Crnojević-Bengin  http://orcid.org/0000-0002-0219-4967

Additional information

Funding

This work has been supported by Ministry of Education, Science and Technological Development, Republic of Serbia within the project III 44006 – Development of new information and communication technologies, based on advanced mathematical methods, with applications in medicine, telecommunications, power systems, protection of national heritage and education.

Notes on contributors

Vasa Radonić

V. Radonić received the B.Sc. M.Sc. and Ph.D. degrees from the University of Novi Sad, Faculty of Technical Sciences, Serbia, in 2004, 2007 and 2010 respectively. He received PhD degree in Electronics and microwave engineering. His current research interests are microfluidics, sensors design, RF and microwave, metamaterials, fabrication technologies.

Slobodan Birgermajer

S. Birgermajer received the M.Sc. and Ph.D. degree in electronics and computer sciences from the Faculty of Technical Sciences, University of Novi Sad, Serbia, in 2011 and 2018, respectively. His current interests are development of RF and microwave passive circuits, metamaterials, microfluidics, 3D printing technologies, and their applications.

Norbert Cselyuszka

N. Cselyuszka received the M.Sc. and Ph.D. degree in electronics and computer engineering from the Faculty of Technical Sciences, University of Novi Sad, Serbia, in 2010 and 2015, respectively. His research interests include electromagnetic and acoustic metamaterials, microwave passive circuits, plasmonics and sensors.

Vesna Crnojević-Bengin

V. Crnojević Bengin obtains B.Sc at University of Novi Sad (UNS) in 1994, M.Sc. at University of Belgrade in 1997, and PhD at UNS in 2006. She is associate professor at FTS, UNS, co-founder of the BioSense Institute, and the member of the Board of Directors of the Innovation Fund, founded by the Serbian Ministry of Science and Technological Development. Her research interests are RF and microwave electronics, artificial electromagnetic and acoustic materials, sensors.