In this paper, we propose and develop a novel reconfigurable bandpass filter based on microstrip LC resonators. The equivalent circuit model of the proposed filter is presented. The filter can be reconfigured by tuning the capacitance of the microstrip LC resonators. A reconfigurable bandpass filter based on semiconductor varactor diode loaded microstrip LC resonators with a tuning range of 2.496 GHz to 2.937 GHz, and a fractional bandwidth of 6.3% to 8.2% is demonstrated, and the measured insertion loss is 1.7 dB to 3.8 dB. The out-band rejection is better than 25 dB up to 10 GHz.
2. Wei, F., L. Chen, X. W. Shi, and C. J. Gao, "UWB bandpass filter with one tunable notch-band based on DGS," Journal of Electromagnetic Waves and Applications, Vol. 26, No. 5-6, 673-680, 2012.
doi:10.1080/09205071.2012.710788
3. Huang, X., Q. Feng, and Q. Xiang, "Bandpass filter with tunable bandwidth using quadruple-mode stub-loaded resonator," IEEE Microw. Wireless Compon. Lett., Vol. 22, 176-178, 2012.
doi:10.1109/LMWC.2012.2188280
4. Liu, B. , F.Wei, H. Zhang, X. Shi, H. Lin, and , "A tunable bandpass filter with switchable bandwidth," Journal of Electromagnetic Waves and Applications,, Vol. 25, No. 2-3, 223-232, 2011.
doi:10.1163/156939311794362704
5. Park, W. Y. and S. Lim, "Bandwidth tunable and compact band-pass filter (BPF) using complementary split ring resonators (CSRRS) on substrate integrated waveguide (SIW)," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 17, 2407-2417, 2010.
doi:10.1163/156939310793675727
6. Hyeon, I. J. , T. J. Jung, S. Lim, and C. W. Baek, "platformed linear/circular polarization reconfigurable antenna using an integrated silicon RF MEMS switch," ETRI Journal, Vol. 33, 802-805, 2011.
doi:10.4218/etrij.11.0210.0422
7. Yoon, W. S., S. M. Han, S. Pyo, J. Lee, I. C. Shin, Y. S. Kim, and , "Reconfigurable circularly polarized microstrip antenna on a slotted ground," ETRI Journal, Vol. 32, 468-471, 2010.
doi:10.4218/etrij.10.0209.0455
8. Erdemli, Y. E. and A. Sondas, "Dual-polarized frequency-tunable composite left-handed slab," Journal of Electromagnetic Waves and Applications, Vol. 19, No. 14, 1907-1918, 2005.
doi:10.1163/156939305775570521
9. Xiang, Q. Y., Q. Y. Feng, and X. G. Huang, "Half-mode substrate integrated waveguide (HMSIW) filters and its application to tunable filters," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 14-15, 2043-2053, 2011.
doi:10.1163/156939311798072027
10. Senior, D. E., X. Cheng, and Y. K. Yoon, "Electrically tunable evanescent mode half-mode substrate-integrated-waveguide resonators," IEEE Microw. Wireless Compon. Lett., Vol. 22, 123-125, 2012.
doi:10.1109/LMWC.2012.2183860
11. Sekar, V. and K. Entesari, "A half-mode substrate-integrated-waveguide tunable filter using packaged RF MEMS switches," IEEE Microw. Wireless Compon. Lett., Vol. 2, 336-338, 2012.
doi:10.1109/LMWC.2012.2199976
12. Lee, J. and K. Sarabandi, "An analytic design method for microstrip tunable filters," IEEE Trans. Microw. Theory Tech., Vol. 56, 1699-1706, Jul. 2008.
13. Xiang, Q. Y., Q. Y. Feng, and X. G. Huang, "A novel microstrip bandstop filter and its application to reconfigurable filter," Journal of Electromagnetic Waves and Applications, Vol. 26, No. 8-9, 1039-1047, 2012.
doi:10.1080/09205071.2012.710365
14. Liu, B., F. Wei, Q. Y. Wu, and X. W. Shi, "A tunable bandpass filter with constant absolute bandwidth," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 11-12, 1596-1604, 2011.
doi:10.1163/156939311797164819
15. 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
16. Hong, J. S., Microstrip Filters for RF/microwave Applications, 2nd Ed., John Wiley & Sons, 2011.
doi:10.1002/9780470937297
17. Radmanesh, M. M., Radio Frequency and Microwave Electronics Illustrated, Prentice Hall, 2001.
18. Patel, C. D. and G. M. Rebeiz, "High-Q 3 b/4 b RF MEMS digitally tunable capacitors for 0.8-3 GHz applications," IEEE Microw. Wireless Compon. Lett., Vol. 22, 394-396, 2012.
doi:10.1109/LMWC.2012.2205301