The Transactions of the Korean Institute of Electrical Engineers C (대한전기학회논문지:전기물성ㆍ응용부문C)

The Korean Institute of Electrical Engineers (대한전기학회)
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Extraction of Design Parameters for Re-entrant Mode Microstrip Directional Coupler with High Directivity Using FE Calculation

유한요소계산을 이용한 고지향성을 갖는 재-진입모드 마이크로스트립 방향성 결합기의 설계 파라미터 추출

  • 김형석 (순천향대 정보기술공학부) ;
  • 박준석 (순천향대 정보기술공학부) ;
  • 안달 (순천향대 정보기술공학부)
  • Published : 2001.05.01
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Abstract

In this paper, we extracted design parameters for re-entrant mode microstrip directional coupler using FE(finite element) calculations. The microstrip directional coupler suffers from a poor directivity due to effect of the inhomogeneous dielectric including both dielectric substrate and air in microstrip transmission lines. Thus, the phase velocity of even mode is not equal to that of odd mode. In order to improve the directivity of microstrip directional coupler, a novel re-entrant mode microstrip directional coupler was employed. In microstrip configuration, the high directivity can be reached by matching the even- and odd-mode effective phase velocities. Through the values of capacitance obtained from 2-dimensional FE calculations, the phase velocities for each mode and the design parameter were extracted for the proposed parallel coupled-line configuration. Based on the extracted design parameter with phase matching condition, we designed and fabricated a 30dB directional coupler at 0.85GHz. Experimental results show good performance with excellent, isolation and directivity.

Keywords

References

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