The Journal of Korean Institute of Electromagnetic Engineering and Science (한국전자파학회논문지)

The Korean Institute of Electromagnetic Engineering and Science (한국전자파학회)
권호 표지
DOI QR코드

DOI QR Code

A Filter Synthesis Method without Bandwidth Reduction for Dual-Band Filters Based on Coupled Lines

결합 선로 이중 대역 필터의 대역폭이 줄지 않는 설계 방법

  • Lee, Seung-Ku (Department of Electrical and Electronic Engineering, Yonsei University) ;
  • Ha, Jung-Je (Department of Electrical and Electronic Engineering, Yonsei University) ;
  • Lee, Yong-Shik (Department of Electrical and Electronic Engineering, Yonsei University)
  • 이승구 (연세대학교 전기전자공학과) ;
  • 하정제 (연세대학교 전기전자공학과) ;
  • 이용식 (연세대학교 전기전자공학과)
  • Accepted : 2010.01.25
  • Published : 2010.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

This paper proposes an improved filter synthesis method for dual-band filters based on coupled lines loaded with shunt stubs. The conventional design method relies on equality of the response of the conventional single-band filter and its dual-band counterpart at two frequencies. On the other hand, the proposed method is based on equivalence of the propagation constants and the image impedances of the two filters. Therefore, the proposed method does not suffer from bandwidth reduction phenomena, which requires complex compensating process in the conventional method. Also, the alternative design parameters provided by the demonstrated method enable to construct dual-band filters with more flexibility. For experimental verification, a Chebyshev type dual-band filter with center frequencies at 1 GHz and 3.5 GHz is designed and fabricated. The measured results are in excellent agreement with the full-wave simulated results.

본 논문에서는 분로 스터브가 연결된 결합 선로로 구성된 이중 대역 필터의 새로운 설계 방법을 제안한다. 이중 대역 필터가 단일 대역 필터와 두 목표 주파수에서 같은 응답 특성을 갖는 조건에 기반한 기존 설계 방법과는 달리 제안하는 설계 방법은 두 필터가 같은 전파 상수와 같은 영상 임피던스를 갖는 조건을 바탕으로 한다. 이는 기존 설계 방법과는 달리 대역폭이 줄어들지 않는 설계 방법으로 복잡한 과정을 통한 대역폭 보상이 필요없으므로 보다 간단한 설계가 가능한 장점이 있다. 또한 새로운 이중 대역 필터 설계 방법을 제공함으로써 보다 유연한 설계를 가능하게 한다. 실험적 검증을 위하여 중심 주파수가 1 GHz와 3.5 GHz인 이중 대역 체비셰프필터를 설계 및 제작하였으며, 측정 결과는 전자기 모의실험 결과와 매우 일치하는 우수한 특성을 보인다.

Keywords

References

  1. C. -W Tang, S. -F. You, "Using the technology of low temperature co-fired ceramic to design the dualband bandpass filter", IEEE Microw. Wireless Compon. Lett., vol. 16, no. 7, pp. 407-409, Jul. 2006. https://doi.org/10.1109/LMWC.2006.877123
  2. C. -W Tang, S. -F. You, and I. -C. Liu, "Design of a dual-band bandpass filter with low temperature cofired ceramic technology", IEEE Trans. Microw. Theory Tech., vol. 54, no. 8, pp. 3327-3332, Aug. 2007. https://doi.org/10.1109/TMTT.2006.879174
  3. H. -M. Lee, C. -M. Tsai, "Dual-band filter design with flexible passband frequency and bandwidth selections", IEEE Trans. Microw. Theory Tech., vol. 55, no. 5, pp. 1002-1009, May 2007. https://doi.org/10.1109/TMTT.2007.895410
  4. S. Lee, Y. Lee, "A planar dual-band filter based on reduced-length parallel coupled lines", IEEE Microw. Wireless Compon. Lett., vol. 20, no. 1, pp. 16-18, Jan. 2010. https://doi.org/10.1109/LMWC.2009.2035953
  5. S. -S. Myoung, Y. Lee, and J. -G. Yook, "Bandwidth-compensation method for miniaturized parallel coupled-line filters", IEEE Trans. Microw. Theory Tech., vol. 55, no. 7, pp. 1531-1538, Jul. 2007. https://doi.org/10.1109/TMTT.2007.900310
  6. G. L. Matthaei, L. Young, and E. M. Jones, Microwave Filters, Impedance-Matching Network, and Coupling Structures, Artech House, Inc., Dedham, Massachusetts, 1980.
  7. D. M. Pozar, Microwave Engineering 3rd Ed., John Wiley & Sons, Inc., Hoboken, NJ, 2005.
  8. C. -M. Tsai, H. -M. Lee, and C. -C. Tsai, "Planar filter design with fully controllable second passband", IEEE Trans. Microw. Theory Tech., vol. 53, no. 11, pp. 3429-3439, Nov. 2005. https://doi.org/10.1109/TMTT.2005.855739
  9. Ansoft Corporation, Pittsburgh, PA, High Frequency Structure Simulator, v10.0, 2005.