volume | PIER Journals

Abstract

This paper presents a third-order digital tunable bandpass filter based on digitally tunable capacitor loaded microstrip open ring resonator. Magnetic dominated mixed coupling is utilized to make the coupling coefficient meet the requirement of stable bandwidth response. Electric source-load coupling is designed to generate a transmission zero for improving the frequency selectivity. This filter is designed, fabricated and measured. The measurement shows that the filter can be digitally tuned by 5-bits pure digital command. The fractional bandwidth is 9±1%, and the tuning range is from 410 MHz to 820 MHz.

1. Asadi, H., H. Volos, M. M. Marefat, and T. Bose, "Metacognition and the next generation of cognitive radio engines," IEEE Communications Magazine, Vol. 54, No. 1, 76-82, 2016.
doi:10.1109/MCOM.2016.7378429

2. Abbaspour-Sani, E., N. Nasirzadeh, and G. R. Dadashzadeh, "Two novel structures for tunable MEMS capacitor with RF applications," Progress In Electromagnetics Research, Vol. 68, 169-183, 2007.
doi:10.2528/PIER06081404

3. Gao, L., X. Y. Zhang, and Q. Xue, "Compact tunable filtering power divider with constant absolute bandwidth," IEEE Trans. Microw. Theory Tech., Vol. 63, No. 10, Oct. 2015.

4. Xiang, Q., Q. Feng, X. Huang, and D. Jia, "Electrical tunable microstrip LC bandpass filters with constant bandwidth," IEEE Trans. Microw. Theory Tech., Vol. 61, No. 3, 1124-1130, 2013.
doi:10.1109/TMTT.2013.2241781

5. Uher, J. and W. J. R. Hoefer, "Tunable microwave and millimeter-wave bandpass filters," IEEE Trans. Microw. Theory Tech., Vol. 39, 643-653, Apr. 1991.
doi:10.1109/22.76427

6. Xiang, Q., Q. Feng, and X. Huang, "Half-mode substrate integrated waveguide (HMSIW) filters and its application to tunable filters," Journal of Electromagnetic Waves and Applications, Vol. 25, 2043-2053, 2011.
doi:10.1163/156939311798072027

7. Huang, X., L. Zhu, Q. Feng, Q. Xiang, and D. Jia, "Tunable bandpass filter with independently controllable dual passbands," IEEE Trans. Microw. Theory Tech., Vol. 61, No. 9, 3200-3208, Sep. 2013.
doi:10.1109/TMTT.2013.2273894

8. Xiang, Q., Q. Feng, and X. Huang, "Substrate integrated waveguide filters and mechanical/ electrical reconfigurable half-mode substrate integrated waveguide filters," Journal of Electromagnetic Waves and Applications, Vol. 26, 1756-1766, 2012.
doi:10.1080/09205071.2012.711526

9. El-Tanani, M. A. and G. M. Rebeiz, "A two-pole two-zero tunable filter with improved linearity," IEEE Trans. Microw. Theory Tech., Vol. 57, No. 4, Apr. 2009.
doi:10.1109/TMTT.2009.2015124

10. Zhang, X. Y., C. H. Chan, Q. Xue, and B.-J. Hu, "RF tunable bandstop filters with constant bandwidth based on a doublet configuration," IEEE Trans. Ind. Electron., Vol. 59, No. 2, 1257-1265, Feb. 2012.
doi:10.1109/TIE.2011.2158038

11. Luo, X., S. Sun, and R. B. Staszewski, "Tunable bandpass filter with two adjustable transmission poles and compensable coupling," IEEE Trans. Microw. Theory Tech., Vol. 62, No. 9, 2003-2013, Sep. 2014.
doi:10.1109/TMTT.2014.2337287

12. Wang, Y., F. Wei, H. Xu, and X.-W. Shi, "A tunable 1.4–2.5GHz bandpass filter based on single mode," Progress In Electromagnetics Research, Vol. 135, 261-269, 2013.
doi:10.2528/PIER12111704

13. Chen, J.-X., J. Shi, Z.-H. Bao, and Q. Xue, "Tunable and switchable bandpass filters using slot-line resonators," Progress In Electromagnetics Research, Vol. 111, 25-41, 2011.
doi:10.2528/PIER10100808

14. Xiang, Q.-Y., Q. Feng, X.-G. Huang, and D.-H. Jia, "A novel microstrip Lc reconfigurable bandpass filter," Progress In Electromagnetics Research Letters, Vol. 36, 171-179, 2013.
doi:10.2528/PIERL12111202

15. Cao, L., G. Li, J. Hu, and L. Yin, "A miniaturized tunable bandpass filter with constant fractional bandwidth," Progress In Electromagnetics Research C, Vol. 57, 89-97, 2015.
doi:10.2528/PIERC15032701

16. Jia, D.-H., Q. Feng, X.-G. Huang, and Q.-Y. Xiang, "A dual-band bandpass filter with a tunable passband," Progress In Electromagnetics Research C, Vol. 37, 107-118, 2013.
doi:10.2528/PIERC12121210

17. Tu, W.-H., "Compact low-loss reconfigurable bandpass filter with switchable bandwidth," IEEE Microw. Wireless Compon. Lett., Vol. 20, No. 4, 208-210, Apr. 2010.
doi:10.1109/LMWC.2010.2042553

18. Ur Rehman, M. Z., Z. Baharudin, M. A. Zakariya, M. H. M. Khir, M. T. Jilani, and M. T. Khan, "RF MEMS based half mode bowtie shaped substrate integrated waveguide tunable bandpass filter," Progress In Electromagnetics Research C, Vol. 60, 21-30, 2015.
doi:10.2528/PIERC15091407

19. Young, R. M., J. D. Adam, et al. "Low-loss bandpass RF filter using MEMS capacitance switches to achieve a one-octave tuning range and independently variable bandwidth," IEEE MTT-S Int. Microw. Symp. Dig., Vol. 3, 1781-1784, 2003.

20. Park, S. J., K. Y. Le, and G. M. Rebeiz, "Low-loss 5.15–5.70-GHz RF MEMS switchable filter for wireless LAN applications," IEEE Trans. Microw. Theory Tech., Vol. 54, No. 11, 3931-3939, Nov. 2006.
doi:10.1109/TMTT.2006.884625

21. El-Tanani, M. A. and G. M. Rebeiz, "High-performance 1.5–2.5-GHz RF-MEMS tunable filters for wireless applications," IEEE Trans. Microw. Theory Tech., Vol. 58, No. 6, Jun. 2010.
doi:10.1109/TMTT.2010.2049166

22., PE64904: 5-bit 32-state Digitally Tunable Capacitor, 100–3000 MHz, Peregrine Semiconductor, 9380 Carroll Park Drive, San Diego, CA 921921, USA.

23. Jaschke, A., M. Tessema, M. Schuhler, and R. Wansch, "Digitally tunable bandpass filter for cognitive radio applications," IEEE 17th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks, 338-342, 2012.

24. Ranta, T. and R. Novak, "New tunable technology for mobile-TV antennas," Microwave Journal, Nov. 2008.

25. Gao, L., X. Y. Zhang, B.-J. Hu, and Q. Xue, "Novel multi-stub loaded resonators and their applications to various bandpass filters," IEEE Trans. Microw. Theory Tech., Vol. 62, No. 5, May 2014.
doi:10.1109/TMTT.2014.2314680

26. Zhao, Z., J. Chen, L. Yang, and K. Chen, "Three-pole tunable filters with constant bandwidth using mixed combline and split-ring resonators," IEEE Microw. Wireless Compon. Lett., Vol. 24, No. 10, Oct. 2014.

27. Chiou, Y.-C. and G. M. Rebeiz, "Tunable 1.55–2.1GHz 4-pole elliptic bandpass filter with bandwidth control and > 50 dB rejection for wireless systems," IEEE Trans. Microw. Theory Tech., Vol. 61, No. 1, 117-124, Jan. 2013.
doi:10.1109/TMTT.2012.2227789

28. Dai, G. L., X. Y. Zhang, C. H. Chan, Q. Xue, and M. Y. Xia, "An investigation of open- and short-ended resonators and their applications to bandpass filters," IEEE Trans. Microw. Theory Tech., Vol. 57, No. 9, 2203-2210, Sep. 2009.
doi:10.1109/TMTT.2009.2027173

29. Zhang, X. Y., Q. Xue, C. H. Chan, and B.-J. Hu, "Low-loss frequency-agile bandpass filters with controllable bandwidth and suppressed second harmonic," IEEE Trans. Microw. Theory Tech., Vol. 58, No. 6, 1557-1564, Jun. 2010.
doi:10.1109/TMTT.2010.2048250

30. Huang, X., Q. Feng, L. Zhu, and Q. Xiang, "A constant absolute bandwidth tunable filter using varactor-loaded open-loop resonators," Asia-Pacific Microwave Conference Proceedings 2013, 872-874, 2013.
doi:10.1109/APMC.2013.6694986

31. Chiou, Y. C. and G. M. Rebeiz, "A quasi elliptic function 1.75–2.25 GHz 3-pole bandpass filter with bandwidth control," IEEE Trans. Microw. Theory Tech., Vol. 60, No. 2, 244-249, Feb. 2012.
doi:10.1109/TMTT.2011.2178260

Dr. Mingye Fu

Professor Qian-Yin Xiang

Dr. Dan Zhang

Dr. Dengyao Tian

Prof. Quanyuan Feng