An 550-650 MHz Digitally-Tunable Bandpass Filter: Design and Implementation

  • Nguyen Xuan Quyen Hanoi University of Science and Technology, Vietnam
  • Vu Dang Quang Hanoi University of Science and Technology, Vietnam


In this paper, a digitally-tunable band-pass filter is designed and implemented for applications of Cognitive Radio in middle Ultra high frequency television band from 550 to 650 MHz. This design is based on the 3th-order Chebyshev filter model in the combination with impedance inverters and series LC resonators, where capacitors are replaced by varactor diodes. The central frequency is tuned by means of a digital control board to adjust DC bias voltages of the diodes. Theoretical analysis, numerical simulation, and hardware implementation are described and carried out. The RF board is fabricated using SMV1736 varactor diodes with FR4-0.8mm material. The results show good match between simulations and measurements in terms of return loss, insertion loss, and fractional bandwidth over the operating range.


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How to Cite
QUYEN, Nguyen Xuan; QUANG, Vu Dang. An 550-650 MHz Digitally-Tunable Bandpass Filter: Design and Implementation. Journal of Science and Technology: Issue on Information and Communications Technology, [S.l.], v. 17, n. 12.2, p. 13-19, dec. 2019. ISSN 1859-1531. Available at: <>. Date accessed: 20 feb. 2020. doi: