Design and Fabrication of Forward -3㏈ Directional Coupler Using Asymmetrical Coupled Lines with Mentalization Thickness

도체두께를 가진 비대칭 결합선로를 이용한 정방향 -3㏈ 방향성 결합기의 설계 및 제작

  • 홍익표 (공주대학교 정보통신공학부) ;
  • 윤남일 (연세대학교 전기전자공학부 전파통신연구실) ;
  • 육종관 (연세대학교 전기전자공학부 전파통신연구실)
  • Published : 2003.08.01

Abstract

In this paper, forward-wave -3㏈ directional coupler with finite-thickness conductor and asymmetrical coupled lines are designed and experimentally verified using mode-matching based design methodology. Most of studies published in the literatures about the coupled lines are mainly concentrated on the adjustment of coupling amount by changing various geometric configurations. The analysis results in this paper show that thicker metalization requires reduced coupler length in the forward-wave directional coupler composed of asymmetrical coupled lines. Several forward-wave directional -3 ㏈ couplers with finite metalization thickness composed of asymmetrical coupled microstrip lines have been designed in the 5 ㎓ based on proposed design method. The measured data show -4.05㏈∼-4.09㏈ coupling at center frequency which is very closed to design value. The tight coupling has been implemented with accurate design methodology which take mentalization thickness into account.

본 논문에서는 모드정합법을 이용하여 도체두께를 고려한 비대칭 결합선로의 특성을 해석하고, 중심주파수 5㎓ 인 정방향 -3㏈ 방향성 결합기를 설계 및 제작하였다. 결합선로의 결합도에 대한 연구는 대부분 기하학적인 구조의 변화에 대해 연구되어 왔으나, 본 논문에서는 도체두께가 비대칭 결합선로의 간격, 선로 폭, 결합기의 길이에 미치는 영향을 이론적으로 분석하고, 도체두께를 고려한 비대칭 결합선로를 이용한 결합기를 설계하여 도체 두께가 두꺼울수록 강한 결합으로 인하여 정방향 결합기의 결합길이가 짧아지고 광대역 특성이 얻어지는 결과를 얻었다. 본 논문에서는 5㎓ 중심주파수로 한 도체두께가 서로 다른 비대칭 결합선로로 구성된 정방향 -3㏈ 결합기를 설계하고, 제작 및 실험을 통하여 약 -4.05㏈∼-4.09㏈의 결합특성을 갖는 주파수특성 측정결과를 얻어 설계 값에 거의 근접하는 것을 확인하였으며, 도체 두께를 고려한 정확한 설계로써 결합선로에서 강한결합과 광대역 특성을 만들 수 있다는 사실을 확인하였다.

Keywords

References

  1. IEEE Trans.Microwave Theory Tech. v.45 Quasi-Static Analysis of Shielded Microstrip Transmission Lines with Thick Electrodes N.H.Zhu;W.Qiu;E.Y.B.Pun;P.S.Chung
  2. IEEE Trans. Microwave Theory Tech. v.42 Quasi-static Analysis of Shielded Planar Transmission Lines with Finite Metallization Thickness by a Mixed Spectral-Space Domain Method G.G.Gentili;G.Macchiarella
  3. IEEE J. Quantum Electron v.27 A Mode Projecting Method for the Quasi-Static Analysis of Electrooptic Device Electrodes Considering Finite Metalization Thickness and Anisotropic Substrate H,Jin;R.Vahldiek;M.Belanger;Z.Jacubczyk
  4. IEEE Trans. Microwave Theory Tech. v.41 Quasi-TEM Description of MMIC Coplanar Lines Including Conductor-Loss Effects W.Heinrich
  5. IEEE Trans. Microwave Theory Tech. v.38 Analysis of a Shielded Microstrip Line with Finite Metallization Thickness by the Boundary Element Method T.Chang;C.Tan
  6. IEEE Trans. Microwave Theory Tech. v.32 The Method of Lines for the Analysis of Planar Waveguides with Finite Metallization Thickness F.J.Schmuckle;R.Pregla
  7. IEEE Microwave and Guided Wave Lett. v.1 New Method for the Analysis of Dispersion Characteristics of Various Planar Transmission Lines with Finite Metallization Thickness L.Zhu;E.Yamashita
  8. Proc. IEEE v.65 Simple and accurate formulas for microstrip with finite strip thickness R.Gang;I.J.Bahl
  9. IEEE Trans. Microwave Theory Tech. v.19 Analysis of Thick-Strip Transmission Lines E.Yamashita;K.Atsuki
  10. IEEE Trans. Microwave Theory Tech v.38 Higher Order Asymptotic Boundary Condition for the Finite Element Modeling of Two-Dimensional transmission Line Structures A.Khebir;A.B.Kouki;R.Mittra
  11. IEEE Trans. Microwave Theory Tech. v.18 Calculation of Coefficients of Capacitance of Multiconductor Transmission Lines in the Presence of a Dielectric Interface W.T.Weeks
  12. IEEE Trans. Microwave Theory Tech. v.35 Application of a Projection Method to a Mode-Matching Solution for Microstrip Lines with Finite Metallization Thickness F.Bogelsack;I.Wolff
  13. IEEE Trans. Microwave Theory Tech. v.38 The Scattering Parameters and Directional Coupled Analysis of Characteristically Terminated Asymmetric Coupled Transmission Lines in an Inhomogeneous Medium K.Sachse
  14. IEEE Trans. Microwave Theory Tech. v.32 Normal-Mode Parameters of MIcrostrip Coupled Lines of Unequal Width S.Kal;D.Bhattacharya;N.B.Chakraborti
  15. IEEE Trans. Microwave Theory Tech. v.32 Characteristics of Some Asymmetrical Coupled Transmission Lines S.S.Bedair
  16. Int. J. Electron v.45 Quasi-TEM Parameters of Non- Symmetrical Coupled Microstrip Lines V.K.Tripathi;C.L.Chang
  17. IEEE Trans. Microwave Theory Tech. v.23 Asymmetric Coupled Transmission Lines in an Inhomogeneous Medium V.K.Tripathi
  18. RF and Microwave Coupled-Line Circuits R.Mongia;I.Bahl;P.Bhartia
  19. IEEE Trans. Microwave Theory Tech. v.41 An MMIC-Compatible Tightly Coupled-Line Structure Using Embedded Microstrip D.Willems;I.Bahl
  20. IEEE Trans. Microwave Theory Tech. v.40 Broadside-Coupled Coplanar Waveguide and Their End- Coupled Band-Pass Filter Application C.Nguyen
  21. IEEE Trans. Microwave Theory Tech. v.35 Wide-Band, Forward-Coupling Microstrip Hybrids with High Directivity P.K.Ikalainen;G.L.Mattaei