Full-wave analysis and design of a new double-sided branch-line coupler and its complementary structure

A new double-sided branch-line coupler using microstrip lines as input/output lines and slotlines as branches is analyzed and designed. The even-odd mode theory is first used to analyze the ideally simplified circuit model and to find out the preliminary circuit dimensions. Based on these dimensions, the full-wave spectral domain approach (SDA) is employed to accurately simulate the circuit performance. By the formulation of the exact Green's function in the spectral domain, the effects of surface wave and radiation phenomena are accurately accounted for. Experimental data agree very well with the SDA simulation results. It is found that the even-odd mode theory which neglects discontinuities between lines is not enough to design a coupler. The SDA code can then be used to accurately simulate and optimize the circuit performance. The complementary structure with slotlines as input/output lines and microstrip lines as branches is also investigated both theoretically and experimentally. It is noticed that the radiation and leakage from the two double-ended branches for all structures will deteriorate the circuit performance. >

[1]  Nicolaos G. Alexopoulos,et al.  DYNAMIC MODEL FOR MICROSTRIP-SLOTLINE TRANSITION AND RELATED STRUCTURES. , 1987 .

[2]  T. Itoh,et al.  Full-wave modeling of coplanar waveguide discontinuities with finite conductor thickness , 1993 .

[3]  T. Ho,et al.  A W-band integrated power module using MMIC MESFET power amplifiers and varactor doublers , 1993 .

[4]  H. Ashoka.  Practical realisation of difficult microstrip line hybrid couplers and power dividers , 1992, 1992 IEEE Microwave Symposium Digest MTT-S.

[5]  Amir Mortazawi,et al.  Coupled slot-strip coupler in finline , 1991, 1991 IEEE MTT-S International Microwave Symposium Digest.

[6]  Kai Chang,et al.  Broad-band uniplanar hybrid-ring and branch-line couplers , 1993 .

[7]  M. Aikawa,et al.  New slot-coupled directional couplers between double-sided substrate microstrip lines, and their applications , 1988, 1988., IEEE MTT-S International Microwave Symposium Digest.

[8]  Mauro Mongiardo,et al.  Analysis of branch line coupler in suspended stripline with finite metallization thickness , 1993, 1993 IEEE MTT-S International Microwave Symposium Digest.

[9]  T. Itoh.  Numerical techniques for microwave and millimeter-wave passive structures , 1989 .

[10]  F. D. Ronde.  A New Class of Microstrip Directional Couplers , 1970 .

[11]  D. Pozar,et al.  Full-Wave Analysis of Microstrip Open-End and Gap Discontinuities , 1985 .

[12]  A. Ittipiboon,et al.  Microstripline-slotline transition analysis using the spectral domain technique , 1992 .

[13]  J. A. Garćıa.  A Wide-Band Quadrature Hybrid Coupler (Correspondence) , 1971 .

[14]  R. K. Hoffmann,et al.  Microstrip-Slot Coupler Design-Part I: S-Parameters of Uncompensated and Compensated Couplers , 1982 .

[15]  Masahiro Muraguchi,et al.  Reduced-size branch-line and rat-race hybrids for uniplanar MMIC's , 1990 .

[16]  M. Aikawa,et al.  Double-sided MICs and their applications , 1989 .

[17]  Nicolaos G. Alexopoulos,et al.  A Dynamic Model for Microstrip--Slotline Transition and Related Structures , 1987, 1987 IEEE MTT-S International Microwave Symposium Digest.

[18]  J. W. Gipprich,et al.  A new class of branch-line directional couplers , 1993, 1993 IEEE MTT-S International Microwave Symposium Digest.

[19]  W.W. Mumford,et al.  Directional Couplers , 1947, Proceedings of the IRE.

[20]  B. Schiek,et al.  Hybrid Branchline Couplers -- A Useful New Class of Directional Couplers , 1974 .

[21]  Tsuneo Tokumitsu,et al.  Multilayer MMIC branch-line coupler and broad-side coupler , 1992, IEEE 1992 Microwave and Millimeter-Wave Monolithic Circuits Symposium Digest of Papers.

[22]  B. Schiek,et al.  Improving the Isolation of 3-dB Couplers in Microstrip-Slotline Technique , 1978 .