Single-wideband and dual-band bandpass filters based on compact quadruple-mode resonator

Abstract

A stub-loaded U-shaped microstrip resonator (U-SLR) exciting two odd-modes and two even-modes and its applications to single-wideband and dual-band bandpass filter (DB-BPF) are introduced. The parallel-coupled lines (PCLs) at input/output (I/O) ports can provide a wideband response by exciting two additional modes in the passband, so-called PCLs modes. In addition to the transmission poles (TPs) in the passband, two transmission zeros (TZs) in the lower and upper stopbands can be created by the loaded stubs. A compact size, high-selectivity, and low insertion loss WB-BPF is designed, fabricated, and tested. Moreover, a compact and low loss DB-BPF with closely spaced passbands is designed and tested. TZ-shifting method is used to design a DB-BPF by splitting the wideband. To achieve this, it is sufficient to change the length of only one of the loaded stubs. The calculated, simulated and measured frequency responses for both single-wideband and DB-BPFs are in very good agreement.

KEYWORDS:

• Stub-loaded U-shaped resonator
• microstrip filters
• wideband filter
• dual-band filter

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK) [grant number 119E476].

Notes on contributors

Ali Kürşad Görür

Ali Kürşad Görür received the B.Sc. degree in electrical and electronics engineering from Hacettepe University, Turkey, in 2009, and the M.Sc. and Ph.D. degrees in electrical and electronics engineering from Pamukkale University, Turkey, in 2011 and 2016, respectively. He was with the Department of Electrical and Electronics Engineering, Pamukkale University, as a Research Assistant, from 2011 to 2016. He joined the Department of Electrical and Electronics Engineering, Nevşehir Haci Bektaş Veli University, Turkey, in 2016, as an Assistant Professor, where he has been an Associate Professor, since 2018. His current research interests include tunable/multi-band planar filters, multiplexers, balun bandpass filters for wireless communication systems, and chipless RFID tags.

Engin Doğan

Engin Doğan received the B.Sc. degree in electrical and electronics engineering from Pamukkale University, Denizli, Turkey, in 2016, and the M.Sc. degree in electrical and electronics engineering from Niğde Ömer Halisdemir University, Niğde, Turkey, in 2019, where he is currently pursuing the Ph.D. degree. He has been a Research Assistant with the Department of Electrical and Electronics Engineering, Niğde Ömer Halisdemir University. His research interests include tunable filters, multiband filters, and chipless RFID tags.

Adnan Görür

Adnan Görür received the B.Sc. degree in electronics engineering from Erciyes University, Kayseri, Turkey, in 1983, the M.Sc. degree from Uludağ Üniversitesi, Bursa, Turkey, in 1987, and the Ph.D. degree from Erciyes University, in 1992. He was appointed as a Research Assistant with the Department of Electronics Engineering, Erciyes University, in July 1984. He became an Assistant Professor, in 1992. In July 1995, he joined the Department of Electrical and Electronics Engineering, Niğde University, Turkey. He became an Associate Professor and a Full Professor with the Department of Electrical and Electronics Engineering, Niğde University, in 1995 and 2005, respectively. He is currently with the Department of Electrical and Electronics Engineering, Niğde Ömer Halisdemir University (formerly Niğde University). His current research interests include microwave circuits, slow-wave structures, and microstrip filters.