A Compact Dual-Band Bandpass Filter Using Coupled Microstrip Lines

ABSTRACT

In this paper, a new compact dual-band bandpass filter (DB-BPF) is proposed using parallel coupled lines. The design method is based on introducing transmission zeros (TZs) in the frequency response of a single-wideband filter. In the proposed structure, three coupled lines and a multi-mode resonator are used to realize the wide bandpass filter. Meanwhile, two coupled lines that are connected at the end and loaded by an open-circuit stub are employed to make a new notch filter. The proposed DB-BPF is designed and fabricated on Rogers RO3210 substrate for Wireless Local Area Networks (WLANs) applications. The simulation results show good agreement with measurements. The measured results exhibit two passbands centered at 2.4 and 5.2 GHz, having an insertion loss of less than 0.1 dB and 0.9 dB, respectively. Low insertion loss, compact size, and high attenuation between two passbands are the main advantages of the proposed DB-BPF.

KEYWORDS:

• Bandpass filter
• Dual-band
• Coupled line
• Multi-mode resonator
• Notch filter

DISCLOSURE STATEMENT

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

Additional information

Notes on contributors

R. Salmani

Reza Salmani received the BSc degree in telecommunications engineering and MSc degree in electronics engineering from University of Birjand, Iran, in 2014 and 2016, respectively. He is currently pursuing PhD at the Department of Electrical and Computer Engineering, University of Birjand, Iran. His research interest is analysis and design of microwave circuits. Email: [email protected].

A. Bijari

Abolfazl Bijari received the BSc degree in telecommunication engineering, and MSc and PhD degrees in electronics engineering from Ferdowsi University of Mashhad (FUM), Iran in 2005, 2007 and 2013, respectively. He is currently an assistant professor of electrical engineering at University of Birjand, Iran. His research interests include RFIC design, microwave filters and MEMS-based devices.

S. H. Zahiri

Seyed Hamid Zahiri received the BSc degree in electronics engineering from the Sharif University of Technology, Tehran, Iran, the MSc degree in electronics engineering from Tarbiat Modares University, Tehran, and the PhD degree in electronics engineering from Ferdowsi University of Mashhad, Iran, in 1993, 1995, and 2005, respectively. He is currently a Professor of electronics engineering at University of Birjand, Iran. His research interests include pattern recognition, swarm intelligence algorithms, AI, and evolutionary algorithms. Email: [email protected].