volume | PIER Journals

Abstract

A novel microstrip bandpass filter with four transmission zeros is proposed. Four transmission zeros close to the passband are realized to improve the selectivity for the passband. A sixth-order passband is realized with two shorted stubs and a dual-mode ring resonator. The transmission zeros near the passband can be adjusted conveniently by only changing the characteristic impedances of the coupled lines. For demonstration, a planar bandpass filter (3-dB bandwidth 21.9%) was designed and fabricated.

1. Wolff, I., "Microstrip bandpass filters using degenerate modes of a microstrip ring resonators," IET Electron. Lett., Vol. 8, 163-164, 1972.
doi:10.1049/el:19720120

2. Hsieh, L. H. and K. Chang, "Compact, low insertion-loss, sharp-rejection, and wide-band microstrip bandpass filters ," IEEE Trans. Microw. Theory Techn., Vol. 51, 1241-1246, 2003.
doi:10.1109/TMTT.2003.809643

3. Hong, J. S. and S. Li, "Theory and experiment of dual-mode microstrip triangular patch resonators and filters," IEEE Trans. Microw. Theory Techn., Vol. 52, 1237-1243, 2004.
doi:10.1109/TMTT.2004.825653

4. Zhang, X. Y. and Q. Xue, "Novel dual-mode dual-band filters using coplanar-waveguide-fed ring resonators," IEEE Trans. Microw. Theory Techn., Vol. 55, 2183-2190, 2007.
doi:10.1109/TMTT.2007.906501

5. Feng, W. J., W. Q. Che, Y. L. Ma, and Q. Xue, "Compact wideband differential bandpass filter using half-wavelength ring resonator," IEEE Microw. Wireless Compon. Lett., Vol. 23, 81-83, 2013.
doi:10.1109/LMWC.2013.2239632

6. Gómez-García, R., J. I. Alonso, and D. Amor-Martin, "Using the branch line directional coupler in the design of microwave bandpass filters," IEEE Trans. Microw. Theory Techn., Vol. 53, 3221-3229, 2005.
doi:10.1109/TMTT.2005.855140

7. Feng, W. J., W. Q. Che, and Q. Xue, "Transversal signal interaction: Overview of high-performance wideband bandpass filters," IEEE Microw. Mag., Vol. 15, 84-96, 2014.
doi:10.1109/MMM.2013.2296216

8. Feng, W. J., W. Q. Che, and Q. Xue, "Compact ultra-wideband bandpass filters with notched bands based on transversal signal-interaction concepts," IET Microw. Antennas Propag., Vol. 7, 961-969, 2013.
doi:10.1049/iet-map.2013.0061

9. Salleh, M., G. Prigent, O. Pigaglio, and R. Crampagne, "Quarter-wavelength side-coupled ring resonator for bandpass filters," IEEE Trans. Microw. Theory Techn., Vol. 56, 156-162, 2008.
doi:10.1109/TMTT.2007.912167

10. Khan, Z., M. Salleh, and N. Z. Zakaria, "Series-cascaded rings dual-band filter," 2010 Asia-Pacific Microwave Conference (APMC), 1758-1760, 2010.

11. Matthaei, G., L. Young, and E. M. T. Jones, Microwave Filters, Impedance Matching Networks and Coupling Structures, Artech House Inc, Norwood, MA, 1985.

Dr. Kuan Deng

Dr. Wenjie Feng

Dr. Zhengyu Chen