DESIGN AND SIMULATION OF A TUNABLE BANDPASS FILTER USING VARACTOR DIODES FOR WIRELESS AND RADAR APPLICATIONS

This article discusses the development of an electronically tunable filter capable of a wide frequency tuning range. Variation of bias (0-5V) changes the center frequency of the filter within 10% while achieving a 1-dB of typical insertion loss. The concept of tuning a filter’s 3-dB bandwidth with voltage is demonstrated and the effect of the bandwidth tuning elements on the tunable filter performance is discussed. The designed filter has a simple structure and the characteristics of wide tuning range of 1800MHz to 2000MHz and low insertion loss of less than -1.20 dB. The tunable bandpass filter can be scaled to the commercial frequencies up to 2.5GHz, offering advantages for most ISM and cellular band applications.

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  • [1] D. M. Pozar, Microwave Engineering, 2nd ed. New York: Wiley, 1998, ch. 8.
  • [2] S. B. Cohn, “Parallel-coupled transmission-line-resonator filters” IEEE Trans. Microw. Theory Tech., vol. MTT-6, no. 4, pp. 223–231, Apr. 1958.
  • [3] J. S. Hong and M. J. Lancaster, “Development of new microstrip pseudo-interdigitalbandpass filters” IEEE Microw. Guided Wave Lett., vol. 5, no. 8, pp. 261–263, Aug. 1995.
  • [4] J. S. Hong and M. J. Lancaster, Microstrip Filter for RF/Microwave Application. New York: Wiley, 2001, ch. 10.
  • [5] S. F. R. Chang, W. L. Chen, S. C. Chang, C. K. Tu, C. L. Wei, C. H. Chien, C. H. Tsai, J. Chen, and A. Chen, “A dual-band RF transceiver for multistandard WLAN applications” IEEE Trans. Microw. Theory Tech., vol. 53, no. 3, pp. 1048–1055, Mar. 2005.
  • [6] J.-R. Lee, J.-H.Cho, and S.-W. Yun, “New compact bandpass filter using microstrip resonators with open stub inverter” IEEE Microw. Guided Wave Lett., vol. 10, no. 12, pp. 526–527, Dec. 2000.
  • [7] S. Amari, K. Hamed, Y. Antar, and A. Freundorfer, “New elliptic microstrip resonator filters” in Proc. Asia–Pacific Microw. Conf., Nov. 2001, pp. 755–758.
  • [8] L. Zhu and W. Menzel, “Compact microstripbandpass filter with two transmission zeros using a stub-tapped half-wavelength line resonator” IEEE Microw. Wireless Compon.Lett., vol. 13, no. 1, pp. 16–18, Jan. 2003.
  • [9] C.-K. Liao, P.-L.Chi, and C.-Y. Chang, “Microstrip realization of generalized Chebyshev filters with box-like coupling schemes” IEEE Trans. Microw. Theory Tech., vol. 55, no. 1, pp. 147–153, Jan. 2007.
  • [10] R. Li and L. Zhu, “Compact UWB Bandpass filter using stub-loaded multiple-mode resonator” IEEE Microw. Wireless Compon.Lett., vol. 17, no. 1, pp. 40–42, Jan. 2007.
  • [11] Q.-X. Chu and S.-T. Li, “CompactUWBbandpass filter with improved upper-stopband performance” Electron. Lett., vol. 44, no. 4, 12, pp. 742–743, Jun. 2008.
  • [12] X. Y. Zhang, J. X. Chen, and Q. Xue, “Dual-band bandpass filter using stub-loaded resonators” IEEE Microw.Wireless Compon.Lett., vol. 17, no. 8, pp. 583–585, Aug. 2007.
  • [13] X. Y. Zhang and Q. Xue, “Novel centrally loaded resonators and their applications to bandpass filter” IEEE Trans. Microw. Theory Tech., vol. 56, no. 4, pp. 913–921, Apr. 2008.
  • [14] P. Mondal and M. K. Mandal, “Design of dual-band bandpass filters using stub-loaded open-loop resonators” IEEE Trans. Microw. Theory Tech., vol. 56, no. 1, pp. 150–155, Jan. 2008.
  • [15] C. F. Chen, T. Y. Huang, and R. B. Wu, “Design of dual- and triple passband filters using alternately cascaded multiband resonators” IEEE Trans. Microw. Theory Tech., vol. 54, no. 9, pp. 3550– 3558, Sep. 2006.
  • [16] C. H. Lee, C. I. G. Hsu, and H. K. Jhuang, “Design of a new tri-band microstrip BPF using combined quarter- wavelength SIRs” IEEE Microw. Wireless Compon.Lett., vol. 16, no. 11, pp. 594–596, Nov. 2006.
  • [17] C.-I. G. Hsu, C.-H. Lee, and Y.-H. Hsieh, “Tri-band bandpass filter with sharp passband skirts designed using tri-section SIRs” IEEE Microw. Wireless Compon.Lett., vol. 18, no. 1, pp. 19–21 Jan. 2008.
  • [18] Q. X. Chu and X. M. Lin, “Advanced triple-band bandpass filter using tri-section SIR” Electron. Lett., vol. 44, no. 4, pp. 295–296, Feb. 2008.
  • [19] A. Simine, D. Kholodnyak, P. Turalchuk, V. Piatnitsa, H. Jantunen, and I. Vendik, Enhancement of inductance Q-factor for LTCC filter design, In 35th European Microwave Conference, Paris, France, 2005, pp. 1319–1322.
  • [20] A Tunable Bandpass Filter Based on Varactor Loaded Split-Ring Resonators Alper Genc and Reyhan Baktur Department of Electrical and Computer Engineering, Microwave and Optical Technology Letters, Volume 51, Issue 10 (p 2394-2396).
  • [21] Sridharan, P., Sreeja, B.S., “Design and analysis of 1–10GHz band selected bandpass filter with broad tunable range” Communications and Signal Processing (ICCSP), 2014 International Conference on , vol., no., pp.303,306, 3-5 April 2014.doi: 10.1109/ICCSP.2014.6949850.
  • [22] Li Gao, Xiu Yin Zhang, Bin Jie Hu, “Tunable dual-band bandpass filter using varactor-loaded short-ended resonators” Wireless Symposium (IWS), 2013 IEEE International , vol., no., pp.1,3, 14-18 April 2013 doi: 10.1109/IEEE-IWS.2013.6616730.
  • [23] Yi-Ming Chen, Sheng-Fuh Chang, Wei-Yang Chen, Bing-Jhang Huang, “Packaged Tunable Bandpass Filters Based on Varactor-Loaded Spiral Combline Topology” Microwave Magazine, IEEE , vol.14, no.1, pp.123,127, Jan.-Feb. 2013 doi: 10.1109/MMM.2012.2226634.
  • [24] Kawai, K., Okazaki, H., Narahashi, S., “Center frequency, bandwidth, and transfer function tunable bandpass filter using ring resonator and J-inverter” Microwave Conference, 2009. EuMC 2009. European, vol., no., pp.1207, 1210, Sept. 29 2009-Oct. 1 2009.