volume | PIER Journals

Abstract

In this paper several Defected Microstrip Structure (DMS) are used to suppress the first and second spurious responses in microstrip hairpin filters. The DMSs are integrated in filter structure, and therefore this method keeps the filter size unchanged. The DMS interconnection disturbs the current distribution only across the strip, thereby giving a modified microstrip line with certain stop band. The undesired spurious harmonics are suppressed through multiple transmission zeros which are added at these frequencies by designed DMSs. Experimental results verify that 25 dB suppression for the first harmonic and 40 dB suppression for the second harmonic, respectively, without affecting the main passband response. There is a good agreement between the simulated and measured results.

1. Hunter, I., Theory and Design of Microwave Filters, IEE Press, London, UK, 2001.
doi:10.1049/PBEW048E

2. Pozar, D. M., Microwave Engineering, 2 Ed., Wiley, New York, 1998.

3. Hong, J. S. and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, Wiley, New York, 2001.
doi:10.1002/0471221619

4. Afkhami, A. and M. Tayarani, "Spurious response suppression in hairpin filter using CSRR merged in the filter structure," Progress In Electromagnetics Research C, Vol. 11, 137-146, 2009.
doi:10.2528/PIERC09102001 Google Scholar

5. Velazquez-Ahumada, M. C., J. Martel, and F. Medina, "Parallel coupled microstrip filters with ground-plane aperture for spurious band suppression and enhanced coupling," IEEE Trans. Microw. Theory Tech., Vol. 52, No. 3, 1082-1086, 2004.
doi:10.1109/TMTT.2004.823593 Google Scholar

6. Wang, S. M., C. H. Chi, M. Y. Hsieh, and C. Y. Chang, "Miniaturized spurious passband suppression microstrip filter using meandered parallel coupled lines," IEEE Trans. Microw. Theory Tech., Vol. 53, No. 2, 747-753, 2005.
doi:10.1109/TMTT.2004.840619 Google Scholar

7. Bonache, J., I. Gil, J. García-García, and F. Martín, "Novel microstrip bandpass filters based on complementary split-ring resonators," IEEE Trans. Microw. Theory Tech., Vol. 54, No. 1, 265-271, 2006.
doi:10.1109/TMTT.2005.861664 Google Scholar

8. Moradian, M. and M. Tayarani, "Spurious-response suppression in microstrip parallel-coupled bandpass filters by grooved substrates," IEEE Trans. Microw. Theory Tech., Vol. 56, No. 7, 1707-1713, 2008.
doi:10.1109/TMTT.2008.925239 Google Scholar

9. Lopetegi, T., M. A. G. Laso, J. Hernandez, M. Bacaicoa, D. Benito, M. J. Garde, M. Sorolla, and M. Guglielmi, "New microstrip `wiggly line' filters with spurious passband suppression," IEEE Trans. Microw. Theory Tech., Vol. 49, No. 9, 1593-1598, 2001.
doi:10.1109/22.942571 Google Scholar

10. Kuo, J. T., W. H. Hsu, and W. T. Huang, "Parallel coupled microstrip filters with suppression of harmonic response," IEEE Microw. Wireless Compon. Lett., Vol. 12, No. 10, 383-385, 2002.
doi:10.1109/LMWC.2002.804559 Google Scholar

11. Kim, B. S., J. W. Lee, and M. S. Song, "An implementation of harmonic-suppression microstrip filters with periodic grooves," IEEE Microw. Wireless Compon. Lett., Vol. 14, No. 9, 413-415, 2004.
doi:10.1109/LMWC.2004.832063 Google Scholar

12. Kim, I. K., N. Kingsley, M. Morton, R. Bairavasubramanian, J. Papapolymerou, M. M. Tentzeris, and J. G. Yook, "Fractal-shaped microstrip coupled-line bandpass filters for suppression of second harmonic," IEEE Trans. Microw. Theory Tech., Vol. 53, No. 9, 2943-2948, 2005.
doi:10.1109/TMTT.2005.854263 Google Scholar

13. Kazerooni, M., A. Cheldavi, and M. Kamarei, "Unit length parameters, transition sharpness and level of radiation in defected microstrip structure (DMS) and defected ground structure (DGS) interconnections," Progress In Electromagnetics Research M, Vol. 10, 93-102, 2009.
doi:10.2528/PIERM09101907 Google Scholar

Dr. Mohammad Naser-Moghadasi

Dr. Mahmoud Alamolhoda

Dr. Bahman Rahmati