The document proposes a method for creating multi-port couplers by mirroring conventional coupler structures. It presents examples of a four-way coupler created by mirroring 90 hybrid couplers and an eight-way coupler created by mirroring Saleh power-dividing couplers. The mirrored structures were able to maintain equal power dividing between ports, stable phase shifting, and good port isolation as demonstrated through simulations and testing of prototypes.

1. PAPER SIMULATION USING ADS CAD:
MIRRORED COUPLING STRUCTURES FOR MICROWAVE
SIGNAL SPLITTING AND COMBINING
Omid Abolghasemi
Dr. Vahid Nayyeri

2. ABSTRACT
•method of creating multi-port couplers by mirroring conventional coupler structures.
•maintain stable phase shifting between ports, equal power dividing, and port
isolation.
•Example structures: a four-way coupler by mirroring 90 hybrid couplers and an eight-
way coupler by mirroring Saleh power-dividing couplers were built and tested
according to the method discussed.
•good match between theoretical analysis and measurements.
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3. INTRODUCTION
•couplers were designed to meet different system requirements, e.g., Wilkinson
couplers [1], 90 quadrature couplers [2], rat-race couplers [3], Lange couplers
[4],Saleh’s multi-way dividers [5], and Bagley polygon couplers[15]–[18]. maintain
stable phase shifting between ports, equal power dividing, and port isolation.
•It is not easy to find new coupler structures, especially those couplers with multi-ports,
equal power division, and stable phase shifting.
•method of creating a new group of coupler structures by mirroring conventional
coupling structures.
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4. I. INTRODUCTION
•A general theoretical S-parameter analysis method is then suggested for such coupler
analysis.
•To validate the method, we derive the S-parameters of a six-port coupler by
mirroring the conventional 90 quadrature couplers, which is compared with Agilent
Technologies’ Advanced Design System (ADS) (computer-aided design (CAD)
software) simulation results.
•In order to validate our design theory, we designed and fabricated a four-way
coupler (by mirroring 90 quadrature couplers) and an eight-way coupler (by
mirroring Saleh’s four-way couplers [5]) according to the theory discussed. Tested
results showed that these couplers maintain useful features of the original couplers,
such as equal power division, stable phase shifting between output ports, and good
isolation between ports.
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5. II. DESIGN THEORY
Fig. 2. (a) Mirrored structures with a transmission line between two
selected ports, and a passive network connecting these two ports with all
other ports. (b) Using the transmission line as mirror edge, new structure
with more input/output ports can be created. note: all impedance used
are normalized impedance, and all lines are 90 in length unless
otherwise stated.
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•for the structure of Fig. 2(a), it is expected
that port P1 and P2 remain isolated and
input power will be equally divided
between port P3 to P6;
•for the mirrored structure of Fig. 2(b), it is
expected that input power is equally
divided between port P3, P4, P6, and
input port P1 will be isolated with port P2
and P5.

6. II. DESIGN THEORY
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7. II. DESIGN THEORY FIG. 2(A) ADS SIMULATION
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8. II. DESIGN THEORY FIG. 2(B) ADS SIMULATION
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9. III. REALIZATION AND TESTS
Fig. 7. Mirrored couplers optimized for
maximizing working bandwidth.(a) Mirrored
quadrature coupler structure. (b) Mirrored Saleh
coupler structure
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•Built & Simulate Two structures: the four-
way coupler shown in Fig. 7(a) and the
eight-way coupler shown in Fig. 7(b). The
commonly used RO4003C 32 mil 1/4-oz
laminate was selected for these coupler
design and fabrication.

10. III. REALIZATION AND TESTS
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TABLE I
•(top) KEY PARAMETERS OF THE
MIRRORED STRUCTURE OF FIG. 7(a)
AFTER OPTIMIZATION. (bottom) KEY
PARAMETERS OF THE MIRRORED
STRUCTURE OF FIG. 7(b) AFTER
OPTIMIZATION
•RO4003C 32 mil 1/4-oz
•obtaining 600-MHz bandwidth
centered at 6.1 GHz

11. III. REALIZATION AND TESTS FIG. 7(A)
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12. III. REALIZATION AND TESTS FIG. 7(A) ADS IDEAL SIMULATION
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13. III. REALIZATION AND TESTS FIG. 7(A) ADS REALIZED SIMULATION
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14. III. REALIZATION AND TESTS FIG. 7(A) ADS REALIZED SIMULATION
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Substrate Definition
•ADS Database
•Rogers RO4000® Series
High Frequency Circuit
Materials Datasheet

15. III. REALIZATION AND TESTS FIG. 7(A) ADS REALIZED SIMULATION
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Substrate Definition
•Layers Setup

16. III. REALIZATION AND TESTS FIG. 7(A)
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Fig. 10. Back-to-back configurations of the designed four-way mirrored
quadrature coupler and high power. (a) Back-to-back connection of the
four-way mirrored quadrature coupler. (b) Four-way power combining using
the designed coupler.

17. III. REALIZATION AND TESTS FIG. 7(A)
IMPORT INTO ADS MOMENTUM
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18. III. REALIZATION AND TESTS FIG. 7(A)
SIMULATION USING ADS MOMENTUM
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19. III. REALIZATION AND TESTS FIG. 7(A)
SIMULATION USING ADS MOMENTUM OUTPUTS
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20. III. REALIZATION AND TESTS FIG. 7(B)
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eight-way coupler shown in Fig. 6(b). The commonly used RO4003C 32 mil 1/4-oz laminate was
selected for these coupler design and fabrication.

21. III. REALIZATION AND TESTS FIG. 7(A)
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22. III. REALIZATION AND TESTS FIG. 7(B) ADS IDEAL SIMULATION
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23. III. REALIZATION AND TESTS FIG. 7(A)
IMPORT INTO ADS MOMENTUM
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24. III. REALIZATION AND TESTS FIG. 7(A)
SIMULATION USING ADS MOMENTUM
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25. III. REALIZATION AND TESTS FIG. 7(A)
SIMULATION USING ADS MOMENTUM OUTPUTS
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26. CONCLUSIONS
1. Shift in Frequency may caused by simulating SMA connectors or other not
mentioned components
2. With the method, it suggests that new coupling structures could be obtained by
mirroring passive structures; and the most important is these mirrored structures
can maintain useful features of the original structures, such as equal power
splitting, stable phase shifting between output ports, good port matching and
isolation, and more.
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27. REFERENCES:
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