Hostname: page-component-8448b6f56d-mp689 Total loading time: 0 Render date: 2024-04-16T18:10:09.948Z Has data issue: false hasContentIssue false

A planar compact dual-band bandpass filter using stepped impedance resonator and interdigital capacitor

Published online by Cambridge University Press:  06 October 2011

Pankaj Sarkar
ECE Department, Institute of Technical Education and Research, Siksha ‘O’ Anusandhan University, Bhubaneswar, Orissa, India
Rowdra Ghatak*
Microwave and Antenna Research Laboratory, ECE Department, National Institute of Technology Durgapur, Durgapur, West-Bengal, India
Manimala Pal
ECE Department, NSHM Knowledge Campus, Durgapur-Group of Institutions, Durgapur, West Bengal, India
Dipak Ranjan Poddar
ETCE Department, Jadavpur University, Kolkata, West Bengal, India
Corresponding author: R. Ghatak Email:


In this paper a dual-band bandpass filter with sharp rejection is proposed. The filter is realized by using two half-wavelength stepped impedance resonators to operate at the passbands 2.5 and 3.5 GHz. To increase the band width further to about 45 MHz at the lower passband and 115 MHz at the higher passband, interdigital capacitors are introduced between resonator and input and output combining network. Measured insertion loss is about 1.45 and 1.7 dB at first and second passbands, respectively. A finite transmission zero in between two passbands at 2.84 GHz is realized to improve the selectivity of the filter. The design procedure to get highly selective response of the proposed filter is explicitly explained. An equivalent circuit model of proposed filter is developed that matches well with measured results.

Research Papers
Copyright © Cambridge University Press and the European Microwave Association 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)



[1]Pozar, D.M.: Microwave Engineering, John Wiley & Sons, Inc., New Delhi, 2005.Google Scholar
[2]Hong, J.S.; Lancaster, M.J.: Microstrip Filter for RF/Microwave Applications, Wiley, New York, 2001.Google Scholar
[3]Sagawa, M.; Makimoto, M.; Yamashita, S.: Geometrical structures and fundamental characteristics of microwave stepped-impedance resonators. IEEE Trans. Microw. Theory Tech., 45 (7) (1997), 10781085.Google Scholar
[4]Zhang, Y.P.; Sun, M.: Dual-band microstrip bandpass filter using stepped-impedance resonators with new coupling schemes. IEEE Trans. Microw. Theory Tech., 54 (10) (2006), 37793785.Google Scholar
[5]Huang, T.-H.; Chen, H.-J.; Chang, C.-S.; Chen, L.-S.; Wang, Y.-H.; Houng, M.-P.: A novel compact ring dual-mode filter with adjustable second-passband for dual-band applications. IEEE Microw. Wirel. Compon. Lett., 16 (6) (2006), 360362.Google Scholar
[6]Chu, Q.-X.; Chen, F.-C.: A compact dual-band bandpass filter using meandering stepped impedance resonators. IEEE Microw. Wirel. Compon. Lett., 18 (5) (2008), 320322.Google Scholar
[7]Wu, B.; Liang, C.-H.; Li, Qi; Qin, P.-Y.: Novel dual-band filter incorporating defected SIR and microstrip SIR. IEEE Microw. Wirel. Compon. Lett., 18 (6) (2008), 392394.Google Scholar
[8]Wu, B.; Liang, C.-H.; Qin, P.-Y.; Li, Q.: Compact dual-band filter using defected stepped impedance resonator. IEEE Microw. Wirel. Compon. Lett., 18 (10) (2008), 674676.Google Scholar
[9]Wu, G.-L.; Mu, W.; Dai, X.-W.; Jiao, Y.-C.: Design of novel dual-band bandpass filter with microstrip meander-loop resonator and CSRR DGS. Prog. Electromagn. Res. 78 ( 2008), 1724.CrossRefGoogle Scholar
[10]Chiou, Y.-C.; Yang, P.-S.; Kuo, J.-T.; Wu, C.-Y.: Transmission zero design graph for dual-mode dual-band filter with periodic stepped-impedance ring resonator. Prog. Electromagn. Res., 108 ( 2010), 2336.Google Scholar