volume | PIER Journals

Abstract

A novel slot-line filter with stop-band up to 30 GHz is proposed in this paper, and the theoretical analysis is illustrated in detail. This filter is designed on a Rogers RT/duroid 5870 substrate. The rectangular micro-strips can generate transmission zero to give a great suppression for the spurious response around 5f₀ while the L slot lines can create transmission zeros to suppress the spurious response around 7f₀, 9f₀ and 11f₀. f₀ is 2.43 GHz in this paper and represents the center frequency of the main passband. The compact size of this novel filter is 23.7 mm * 14.725 mm (0.152λ * 0.103λ (λ is the working wavelength of this filter)). Besides, the external quality factor of this filter can be as high as about 29.6. To demonstrate the transmission function, the compact filter has been fabricated and the measured results show the feasibility of this structure.

1. Mo, , S.-G., Z.-Y. Yu, and L. Zhang, "Design of triple-mode bandpass Filter using improved hexagonal loop resonator," Progress In Electromagnetics Research, Vol. 96, 117-125, 2009.
doi:10.2528/PIER09080304 Google Scholar

2. Coudos, S. K., Z. D. Zaharis, and T. V. Yioultsis, "Application of a differential evolution algorithm with strategy adaptation to the design of multi-band microwave filters for wireless communications," Progress In Electromagnetics Research, Vol. 109, 123-137, 2010.
doi:10.2528/PIER10081704 Google Scholar

3. Wu, L.-S., J.-F. Mao, W. Shen, and W.-Y. Yin, "Extended doublet bandpass filters implemented with microstrip resonator and full-/half-mode substrate integrated cavities," Progress In Electromagnetics Research, Vol. 108, 433-447, 2010.
doi:10.2528/PIER10081206 Google Scholar

4. Chiou, Y.-C., P.-S. Yang, J.-T. Kuo, and C.-Y.Wu, "Transmission zero design graph for dual-mode dual-band filter with periodic stepped-impedance ring resonator," Progress In Electromagnetics Research, Vol. 108, 23-36, 2010.
doi:10.2528/PIER10071608 Google Scholar

5. Wang, X.-H., B.-Z. Wang, and K. J. Chen, "Compact broadband dual-band bandpass Filters using slotted ground structures," Progress In Electromagnetics Research, Vol. 82, 151-166, 2008.
doi:10.2528/PIER08030101 Google Scholar

6. Wen, C.-P., "Coplanar waveguide, a surface strip transmission line suitable for nonreciprocal gyromacnetic device applications," Microwave Symposium, G-MTT International, 110-115, 1969. Google Scholar

7. Wada, K. and I. Awai, "Heuristic models of half-wavelength resonator bandpass filter with attenuation poles," Electronics Letters, Vol. 35, No. 5, 401-402, Mar. 1999.
doi:10.1049/el:19990207 Google Scholar

8. William, D. F. and S. E. Schwarz, "Design and performance of coplanar waveguide bandpass filters," IEEE Trans. on Microwave Theory and Tech., Vol. 31, No. 7, 558-566, Mar. 1983.
doi:10.1109/TMTT.1983.1131545 Google Scholar

9. Sanada, A., H. Takehara, and I. Awai, "Design of the CPW in-line λ/4 stepped-impedance resonator bandpass filter," Asia-Pacific Microwave Conference Proceedings, APMC, Vol. 2, 633-636, 2001. Google Scholar

10. Lin, S.-C., T.-N. Kuo, Y.-S. Lin, and C.-H. Chen, "Novel coplanar-waveguide bandpass filters using loaded air-bridge enhanced capacitors and broadside-coupled transition structures for wideband spurious suppression," IEEE Trans. on Microwave Theory and Tech., Vol. 54, No. 8, 3359-3369, Aug. 2006.
doi:10.1109/TMTT.2006.879175 Google Scholar

11. Chen, C.-F., T.-Y. Huang, and R.-B. Wu, "Design of microstrip bandpass filters with multi-order spurious-mode suppression," IEEE Trans. on Microwave Theory and Tech., Vol. 53, No. 12, 3788-3793, Dec. 2005.
doi:10.1109/TMTT.2005.859869 Google Scholar

12. Kuo, J.-T. and E. Shih, "Microstrip stepped impedance resonator bandpass filter with an extended optimal rejection bandwidth," IEEE Trans. on Microwave Theory and Tech., Vol. 51, No. 5, 1554-1559, May 2003.
doi:10.1109/TMTT.2003.810138 Google Scholar

13. Kim, I., 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. on Microwave Theory and Tech., Vol. 53, No. 9, 2943-2948, Sep. 2005.
doi:10.1109/TMTT.2005.854263 Google Scholar

14. Luo, X., J.-G. Ma, and E.-P. Li, "Bandpass filter with wide stopband using broadside-coupled microstrip T-stub/DGS cell," Microwave and Optical Technology Letters, Vol. 53, No. 8, 1786-1789, Aug. 2011.
doi:10.1002/mop.26101 Google Scholar

15. Wang, L. G. and L. Jin, "A quasi-elliptic microstrip bandpass filter using modified anti-parallel coupled-line," Progress In Electromagnetics Research, Vol. 138, 245-253, 2013. Google Scholar

16. Luo, X. and J.-G. Ma, "Compact slot-line bandpass filter using backside microstrip open-stubs and air-bridge structure for spurious suppression," Asia-Pacific Microwave Conference Proceedings, APMC, 882-885, 2009. Google Scholar

17. Hong, J.-S. and M.-J. Lancaster, "Couplings of microstrip square II open-loop resonators for cross-coupled planar microwave filters," IEEE Trans. on Microwave Theory and Tech., Vol. 44, No. 12, 2099-2109, Dec. 1996.
doi:10.1109/22.543968 Google Scholar

18. Wu, Y.-L., C. Liao, and X.-Z. Xiong, "A dual-wideband bandpass filter based on E-shaped microstrip sir with improved upper-stopband performance," Progress In Electromagnetics Research, Vol. 108, 141-153, 2010.
doi:10.2528/PIER10071802 Google Scholar

19. Kuo, J.-T., C.-Y. Fan, and S.-C. Tang, "Dual-wideband bandpass filters with extended stopband based on coupled-line and coupled three-line resonators," Progress In Electromagnetics Research, Vol. 124, 1-15, 2012.
doi:10.2528/PIER11120103 Google Scholar

20. Mashhadi, M. and N. Komjani, "Design of dual-band bandpass filter with wide upper stopband using sir and GSIR structures," Progress In Electromagnetics Research, Vol. 32, 221-232, 2012. Google Scholar

21. Tiwary, A. K. and N. Gupta, "Design of compact coupled microstrip line band pass filter with improved stopband characteristics," Progress In Electromagnetics Research, Vol. 24, 97-109, 2011. Google Scholar

22. Lin, W.-J., C.-S. Chang, and J.-Y. Li, "Improved compact broadband bandpass filter using branch stubs co-via structure with wide stopband characteristics," Progress In Electromagnetics Research, Vol. 5, 45-55, 2008. Google Scholar

23. Lin, S.-C. and C.-Y. Yeh, "Stopband-extented balanced filters using both λ/4 and λ/2 sirs with common-mode suppression and improved passband selectivity," Progress In Electromagnetics Research, Vol. 128, 215-228, 2012. Google Scholar

24. Kim, C.-S., D.-H. Kim, I.-S. Song, K. M. K. H. Leong, T. Itoh, and D. Ahn, "A design of a ring bandpass filters with wide rejection band using DGS and spur-line coupling structures," IEEE MTT-S International Microwave Symposium, Vol. 128, 2183-2186, 2005. Google Scholar

25. Kuo, J.-T. and E. Shih, "Microstrip stepped impedance resonator bandpass filter with an extended optimal rejection bandwidth," IEEE Trans. on Microwave Theory and Tech., Vol. 51, 1554-1559, 2003. Google Scholar

26. Chen, C.-F., T.-Y. Huang, and R.-B. Wu, "Design of microstrip bandpass filters with multiorder spurious-mode suppression," IEEE Trans. on Microwave Theory and Tech., Vol. 53, 3788-3793, 2005.
doi:10.1109/TMTT.2005.859869 Google Scholar

Dr. Fang Xu

Dr. Mi Xiao

Mr. Zongjie Wang

Dr. Jiayang Cui

Dr. Zhe Zhu

Dr. Mu Ju

Dr. Jizong Duan