Progress In Electromagnetics Research
ISSN: 1070-4698, E-ISSN: 1559-8985
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By Y. Wang, F. Wei, H. Xu, and X.-W. Shi

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A new type of varactor-tuned microstrip bandpass filter (BPF) based on a single 1/2λ resonator is investigated. The proposed resonator is composed of a transmission line with both ends short-ended and two varactors inserted symmetrically in the middle section. The variation of coupling coefficient can be controlled by using an inductor. With the proposed structure, it is easy to adjust the external quality factor of the filter and to control the bandwidth. Extra dc-block capacitors for the input and output ports are not necessary because the design of the proposed tunable 1/2λ resonator makes the varactor act as both a frequency tuning element and a dc-block circuit. The proposed BPF is found to have the advantages of compact size, low insertion loss, large tuning range and good linearity.

Y. Wang, F. Wei, H. Xu, and X.-W. Shi, "A Tunable 1.4-2.5 GHz Bandpass Filter Based on Single Mode," Progress In Electromagnetics Research, Vol. 135, 261-269, 2013.

1. 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.

2. Lee, , W.-S., , H.-L. Lee, K.-S. Oh, and J.-W. Yu, "Switchable distance-based impedance matching networks for a tunable HF system," Progress In Electromagnetics Research, Vol. 128, 19-34, 2012.

3. Michalski, , J. J., "Inverse modeling in application for sequential filter tuning," Progress In Electromagnetics Research, Vol. 115, 113-129, 2011.

4. Feng, , T., , Y. Li, H. Jiang, W. Li, F. Yang, X. Dong, and H. Chen, "Tunable single-negative metamaterials based on microstrip transmission line with varactor diodes loading," Progress In Electromagnetics Research, Vol. 120, 35-50, 2011.

5. Costa, , F., A. Monorchio, and , "Design of subwavelength tunable and steerable fabry-perot/leaky wave antennas," Progress In Electromagnetics Research, Vol. 111, 467-481, 2011.

6. Wu, , C.-J., , Y.-C. Hsieh, and H.-T. Hsu, "Tunable photonic band gap in a doped semiconductor photonic crystal in near infrared region," Progress In Electromagnetics Research, Vol. 114, 271-283, 2011.

7. Zhang, , H.-L., , X. Y. Zhang, and B.-J. Hu, "Tunable bandpass filters with constant absolute bandwidth," Antennas Propagation and EM Theory (ISAPE), 1200{-1203, 2010.

8. Chiou, , Y.-C. , G. M. Rebeiz, and , "A tunable three-pole 1.5--2.2 GHz bandpass filter with bandwidth and transmission zero control," IEEE Trans. on Microw. Theory and Tech. , Vol. 59, No. 11, 2872-2878, 2011.

9. Sanchez-Renedo, , M., , R. Gomez-Garcia, J. I. Alonso, and C. Briso-Rodriguez, "Tunable combline filter with continuous control of center frequency and bandwidth," IEEE Trans. on Microw. Theory and Tech., Vol. 53, No. 1, 191-199, 2005..

10. Serrano, , A. L. C., F. S. Correra, T.-P. Vuong, and P. Ferrari, "Synthesis methodology applied to a tunable patch filter with independent frequency and bandwidth control," IEEE Trans. on Microw. Theory and Tech, Vol. 60, No. 3, 484-493, 2012.

11. Wang, Y.-Y., F. Wei, B. Liu, H. Xu, and X.-W. Shi, , "A tunable bandpass filter with constant absolute bandwidth based on one ring resonator," Journal of Electromagnetic Waves and Applications, Vol. 26, No. 11--12, 1587-1593, 2012.

12. Hong, J.-S. , M. J. Lancaster, and , Microstrip Filters for RF/Microwaves Applications, Wiley, New York, 2001.

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