US3617952A - Stepped-impedance directional coupler - Google Patents

Stepped-impedance directional coupler Download PDF

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Publication number
US3617952A
US3617952A US854360A US3617952DA US3617952A US 3617952 A US3617952 A US 3617952A US 854360 A US854360 A US 854360A US 3617952D A US3617952D A US 3617952DA US 3617952 A US3617952 A US 3617952A
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microwave energy
parallel
coupling device
directional coupling
stepped
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Expired - Lifetime
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US854360A
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English (en)
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Elmer E Beech
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International Business Machines Corp
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International Business Machines Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P5/00—Coupling devices of the waveguide type
    • H01P5/12—Coupling devices having more than two ports
    • H01P5/16—Conjugate devices, i.e. devices having at least one port decoupled from one other port
    • H01P5/18—Conjugate devices, i.e. devices having at least one port decoupled from one other port consisting of two coupled guides, e.g. directional couplers
    • H01P5/184—Conjugate devices, i.e. devices having at least one port decoupled from one other port consisting of two coupled guides, e.g. directional couplers the guides being strip lines or microstrips
    • H01P5/185—Edge coupled lines

Definitions

  • PATENTED NUV2 IHYI SHEET 1 OF 2 nndr STEPPED-IMPEDANCE DIRECTIONAL COUPLER BACKGROUND OF THE INVENTION This invention relates to directional couplers and more particularly to microwave energy directional coupling devices of the stepped-impedance type.
  • Microwave energy directional couplers of the stepped-impedance type are well known in the art and described, for example, in the literature such as: "Theory and Tables of Optimum Symmetrical TEM-Mode Coupled-Transmission-Line Directional Couplers," E. G. Cristal and L. Young, IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-l3, No. 5, pages 544-558, Sept. l965;Characteristic Impedances of Broadside-Coupled Strip Transmission Lines," S. B. Cohn, IRE Transactions on Microwave Theory and Techniques, Vol. MTT-B, pages 633-637, Nov. 1960; "Impedances of Offset Parallel-Coupled Strip Transmission Lines, J. P. Shelton, Jr., IEEE Transactions on Microwave Theory and Techniques, Vol. MIT-l4, No. 1, pages 7-15, Jan., 1966; to name just a few.
  • the prior art recognized that the shape ofthe transition region associated with a pair of adjacent quarterwavelength sections of the aforedescribed type of directional couplers effected the coupling between the adjacent sections; c.f., for example, the publication entitled The Design and Construction of Broadband, I-Iigh-Directivity, 90 Couplers Using Nonunifonn Line Techniques, C. P. Tresselt, IEEE Transactions on Microwave Theory and Techniques,
  • edges of the transition region were generally provided in a parallel and/or colinear relationship with respect to each other.
  • edges of the transition region between two adjacent quarterwavelength sections were provided with 45 miters, c.f. the article entitled “Tandem Couplers and PhaseShifters for Multi- Scripte Bandwidth,” J. P. Shelton, .I. Wolfe, and R. C. Van- Wagoner, Microwaves, pages 14-19, Apr., 1965; or perpendicularly aligned miters, c.f. the article entitled “Tables for Asymmetric Multi-Element Coupled-Transmission-Line Directional Couplers," R. Levy, IRE Transactions on Microwave Theory and Techniques, Vol. M'IT-l2, pages 27$-279, May, 1964.
  • a microwave energy stepped-impedance directional coupling device which has plural cascaded quarter-wavelength sections of parallelcoupled transmission lines, is provided with a transitionregion for at least one pair of adjacent sections that has sloped edges which are disposed in an oblique relationship with respect to each other.
  • FIG. 1 is a plan view partially broken away of a preferred embodiment of the directional coupler of the present invention
  • FIG. 2 is an enlarged cross-sectional view of the coupler of FIG, 1 taken along the line 2-2 shown in FIG. I, the vertical dimensions of FIG. 2 being exaggerated with respect to the horizontal dimensions thereof for sake of clarity;
  • FIG. 3a is an enlarged schematic diagram of thetransmission line conductors of the embodiment of FIG. 1;
  • FIGS. 3b -3c are enlarged partial schematic diagrams of the transmission line conductors of certain directional couplers of the prior art.
  • FIG; 4 are idealized waveforms of the coupling response characteristic of a typical directional coupler'of the present invention.
  • FIGS. 1-2 there is shown a preferred embodiment of the microwave energy stepped impedance directional coupling device 10 of the present invention.
  • Device or coupler 10 has plural cascaded quarter-wavelength sections of parallel-coupled transmission lines ll, 12.
  • the directional coupler 10 b configuredas a stripline type. Accordingly, each of the transmission line conductors l1 and 12 have a flat or planar configuration.
  • the conductors 11 and 12 are disposed in parallel planes with a predetermined spacing S.
  • Conductors ll, 12 are preferably disposed with their planar configurations parallel to t'he planes of the ground plane members 13, 14.
  • the conductors l1, l2' may be disposed with their respective planar configurations normal to the respective planes of the members 13, 14.
  • a solid dielectric means 15-17 is provided between the spaced ground plane members 13, I4 and spaced conductors ll, 12. More particularly, as shown in FIG. 2, the transmission lines l1, 12 are supported by an inner dielectric planar member 16. The remote outer surfaces of the conductors l1 and 12 are disposed adjacent to the outer dielectric planar members 15 and 17, respectively.
  • the vertical dimensions are illustrated exaggerated relative to the horizontal dimensions for purposes of clarity.
  • the respective vertical spacings shown between the remote outer surfaces of the conductors ll, 12 and the members 15 and 17, respectively, are greatly exaggerated and it should be understood that in practice those spacings would be negligible and/or practically nonexistent.
  • the conductors ll, 12 are preferably formed on the center dielectric member [6 by a printed circuit process or the like. In this manner, the conductors ll, 12 are maintained in a permanent registration or alignment with respect to each other.
  • the conductors ll, 12 may be formed on the respective inner surfaces of the members 15 and 17, respectively, and auxiliary registration means such as alignment pins may be provided on the members 15 and 17 to keep the conductors in the desired aligned relationship with respect to each other.
  • the solid dielectric means 15-17 also provide the means for supporting the conductors I1 and 12. It should be understood that the invention may alternatively be practiced with a gaseous type dielectric such as air, for example, in which case independent supporting means would be provided.
  • the solid dielectric member's 15-17 are made of polyol'efm.
  • the ends of conductor 12 are connected to respective coaxial connectors 18, 19 and the conductor 12 functions as the through conductor.
  • One end of conductor 11 is connected to a coaxial connector 20.
  • the other end of conductor 11 is connected by solder, not shown, or the like, to a terminating impedance such as the resistor 21 via the latters center conductive tap or terminal 21a in a manner and for purposes well known to those skilled in the art.
  • the conductor 11 functions as the coupling conductor.
  • the connectors 1B 19, 20 have the protruding ends of their respective center conductors 18a, 19a, 20a shaped and connected by solder, or the like, to the appropriate ends of conductors 11, 12.
  • Annular openings 22 are provided in the members 15-17 for housing the cylindrical shaped resistor 21.
  • a pair of annular spring-plate like conductive members 23, 24 are juxtaposed between the end surfaces of the resistor 21 and the cylindrical disk-shaped conductive members 25, 26.
  • Members 25, 26, are seated in annular recesses provided in the members 13 and 14, respectively, for this purpose.
  • Each of the two end surfaces of resistor 21 is a terminal.
  • two symmetrical conductive paths connecting the conductor 11 to the ground planes 13, 14 are provided via the resistors center tap 21a and end terminals.
  • Resistors of the type employed for resistor 21 are well known in the art and a typical commercially available resistor suitable for this purpose is referred to by the manufacturer as a "pill resistor or termination. In the preferred embodiment, a conventional microwave 50 ohm termination is used.
  • assembly 11-17 The sides of assembly 11-17 are inserted and mounted in the U-shaped channel formed in the conductive side members 27, 28. Assembly 11-17 is secured thereto by suitable means such as the machine screws 29 which pass through the members 13-17 which are appropriately bored, the channel members being appropriately threaded to receive the screws 29.
  • suitable means such as the machine screws 29 which pass through the members 13-17 which are appropriately bored, the channel members being appropriately threaded to receive the screws 29.
  • the ends of the assembly 11-17 are inserted and mounted in the respective U-shaped channel portions 30 formed in the end conductive members 31, 32 and secured thereto by machine screws 29'.
  • the members 13-17 are provided with appropriate bore holes and the U-shaped portions 30 of the members 31, 32 appropriately threaded for securing the screws 29'.
  • the members 27, 28 and 31, 32 are countoured for compatible mating and thus provide a shielding enclosure which prevents leakage of the microwave energy from the sides or ends of the coupler 10. Screws 29, 29' are also judiciously spaced to prevent or mitigate any unwanted or spurious reflections of microwave energy in the coupler as a result of their presence. Members 27 and 28 are also threaded to receive the machine screws, e.g. screws 18. These screws secure the respective connectors 18-20, and more particularly, the ground conductor housings thereof, to the members 27 and 28 and hence connect the ground plane members 13 and 14 thereto.
  • the assembly 11-17 is held together by a pair of bolts 33 and nuts 34.
  • a pair of hollow bolts 35 which are secured to the assembly 11-17 by the nuts 36, may be provided for mounting the device 10 to an equipment frame, not shown.
  • a pair of threaded pins, not shown, which are mounted on the frame, are adapted to pass through the hollow bolts 35.
  • a pair of nuts, not shown, are fitted to the pins, thus securing the device 10 to the frame.
  • members 13-17 are provided with compatibly bored holes.
  • the through conductor 12 is illustrated in solid line form and superimposed over the coupled conductor 11 shown in dash line form for sake of clarity.
  • the directional coupler 10 is comprised of nine stepped-impedance quarter-wavelength sections designated Z1, Z2 Z9, respectively. It should be noted that each quarter-wavelength section includes parallelcoupled portions of conductors 11 and 12.
  • the conductors l1 and 12 are symmetrically configured.
  • the center portions of the conductors 11, 12 corresponding to the center section Z5 are broadside coupled, whereas the portions of the conductors 11, 12 of any particular one of the other sections are offset coupled. For a given center frequency fc and corresponding wavelength he the dimension Ac/4 is obtained.
  • the widths S1. S2, S9 of the conductors 11, 12 as well as the offset dimension WC1-WC4, WC6-WC9, and the aforementioned spacing dimensions S and b, WC6-WC9, FIG. 2 are readily calculated.
  • the aforementioned dimensions may be obtained from the first three aforementioned publications by Crystal and Young, Cohn, and Shelton, Jr. The symmetrical configuration shown in FIG.
  • the transition region between a pair of adjacent steppedirnpedance quarter-wavelength sections had edges 37 which were in a colinear relationship with respect to each other as shown in FIG. 3b or in a parallel relationship with respect to each other as shown in FIG. 3c. More particularly; with respect to FIG. 30, the angles Band 02 were made equal and preferably were 45, as aforementioned.
  • each of the edges 37 of the particular transition region are disposed in an oblique relationship with respect to the other edges 37 of the particular region.
  • each of the transition regions of each pair of adjacent quarter-wavelength sections has its sloped edges configured in the aforedescribed oblique relationship with respect to each other.
  • the horizontal dimension L of the transition region is detennined from the equation:
  • K is a constant equal to 0.14810025;
  • the horizontal dimension L is symmetrically disposed about and is at right angles to the particular terminating line 38 which is common to the particular pair of adjacent quarter-wavelength sections.
  • Each sloped edge 37' is then configured to pass through the center point of the particular vertical dimension, e.g. H1 or H2, which lies between the two particular horizontal parallel edges of the adjacent quarter-wavelength sections which are to be connected by the particular sloped edge.
  • the width dimensions e.g., S2 and S3
  • the differences in the offset dimensions e.g., WC2 and WC3, provided for the different pairs of adjacent quarter-wavelength sections; e.g.
  • those portions of the conductors 11 and 12 associated with the end quarter-wavelength sections Z1 and Z9 are connected to vertical portions 39.
  • the latter have conventional and 45 miter corners connecting the particular vertical portions 39 with the particular horizontal portions of the end sections Z1 and Z9.
  • FIG. 4 there is shown typical coupling response characteristic curves Ia, lb of the coupled conductor or arm 11 and the through conductor or arm 12, respectively, of the device 10 and the improved ripple characteristics Aa and Ab, respectively.
  • FIG. 4 the corresponding response characteristic curves Ila, IIb shown in dashline form for a comparable nine-section stepped-impedance quarter-wavelength directional coupler which did not employ sloping edges in the transition regions in the manner taught by the present invention.
  • microwave energy is preferably fed into one port; i.e. connector 18, and is transmitted out the other ports; i.e. connectors 19,20.
  • a microwave energy stepped-impedance directional coupling device having plural cascaded quarter-wavelength sections of parallel-coupled transmission lines, the transition region of at least one pair of adjacent said sections being comprised with sloped edges, said edges being disposed in an oblique relationship with respect to each other.
  • a microwave energy stepped-impedance directional coupling device according to claim 1 wherein said device is of the stripline type.
  • a microwave energy directional coupling device comprising:
  • predetermined dielectric means disposed between said first and second ground plane members, said first and second conductors being disposed within said dielectric means
  • a microwave energy directional coupling device according to claim 4 wherein said device is of the stripline type.
  • a microwave energy directional coupling device wherein the transition region has a horizontal dimension parallel to the longitudinal direction of the parallelcoupled transmission lines, said horizontal dimension being equal to where K is a constant equal to 0.l48i0.025; and Ac is the wavelength of the center frequency of said device.
  • a microwave energy directional coupling device according to claim 4 wherein said predetermined dielectric means are of the solid type.
  • a microwave energy directional coupling device according to claim 7 wherein said means for supporting and said predetermined dielectric means are the same.

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US854360A 1969-08-27 1969-08-27 Stepped-impedance directional coupler Expired - Lifetime US3617952A (en)

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GB (1) GB1257906A (enrdf_load_stackoverflow)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3768042A (en) * 1972-06-07 1973-10-23 Motorola Inc Dielectric cavity stripline coupler
US3777284A (en) * 1972-03-27 1973-12-04 Us Navy Directional phase-shifting coupler
US4647878A (en) * 1984-11-14 1987-03-03 Itt Corporation Coaxial shielded directional microwave coupler
US4729510A (en) * 1984-11-14 1988-03-08 Itt Corporation Coaxial shielded helical delay line and process
US5521563A (en) * 1995-06-05 1996-05-28 Emc Technology, Inc. Microwave hybrid coupler
WO1998024141A1 (en) * 1996-11-26 1998-06-04 Raytheon Company Alignment tolerant overlay directional coupler
US5939952A (en) * 1996-05-24 1999-08-17 Molex Incorporated Flat flexible cable with pseudo-twisted conductors
US6300846B1 (en) 1999-03-18 2001-10-09 Molex Incorporated Flat flexible cable with ground conductors
US20040160291A1 (en) * 2003-02-14 2004-08-19 Microlab/Fxr Microwave coupler
US20050146393A1 (en) * 2004-01-02 2005-07-07 Lu Chen High power directional coupler
US20090033802A1 (en) * 2004-09-10 2009-02-05 Comtech S.R.L. Hybrid Coupler and UHF Television Channel Mixer Comprising Such a Hybrid Coupler
US20110051292A1 (en) * 2009-08-31 2011-03-03 Western Digital Technologies, Inc. Disk drive comprising impedance discontinuity compensation for interconnect transmission lines
US8289656B1 (en) 2008-11-19 2012-10-16 Western Digital Technologies, Inc. Disk drive comprising stacked and stepped traces for improved transmission line performance
US8467151B1 (en) 2010-05-21 2013-06-18 Western Digital Technologies, Inc. Disk drive comprising an interconnect with transmission lines forming an approximated lattice network
US8749989B1 (en) 2009-12-28 2014-06-10 Scientific Components Corporation Carrier for LTCC components
US8879212B1 (en) 2013-08-23 2014-11-04 Western Digital Technologies, Inc. Disk drive suspension assembly with flexure having dual conductive layers with staggered traces
EP2697861A4 (en) * 2011-04-11 2014-11-12 Lockheed Corp BROADBAND MICROWAVE HYBRID COUPLER WITH ANY PHASE SHIFT AND SPLIT POWER
CN106165194A (zh) * 2014-03-20 2016-11-23 凯瑟雷恩工厂两合公司 多级的宽带定向耦合器
US20170237140A1 (en) * 2016-02-17 2017-08-17 Eagantu Ltd. Wide band directional coupler
US20190067785A1 (en) * 2017-08-29 2019-02-28 Analog Devices, Inc. Broadband radio frequency coupler
US12004289B2 (en) * 2018-11-14 2024-06-04 Murata Manufacturing Co., Ltd. Flexible substrate and electronic device

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4027254A (en) * 1975-02-11 1977-05-31 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Directional coupler having interdigital comb electrodes
FR2505558A1 (fr) * 1981-05-08 1982-11-12 Cables De Lyon Geoffroy Delore Boitier pour coupleur directif coaxial

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Tandem Couplers and Phase Shifters for Multi-Octave Bandwidth Shelton et al. in Microwaves April 1965 pages 14 19 *

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3777284A (en) * 1972-03-27 1973-12-04 Us Navy Directional phase-shifting coupler
US3768042A (en) * 1972-06-07 1973-10-23 Motorola Inc Dielectric cavity stripline coupler
US4647878A (en) * 1984-11-14 1987-03-03 Itt Corporation Coaxial shielded directional microwave coupler
US4729510A (en) * 1984-11-14 1988-03-08 Itt Corporation Coaxial shielded helical delay line and process
US5521563A (en) * 1995-06-05 1996-05-28 Emc Technology, Inc. Microwave hybrid coupler
US5939952A (en) * 1996-05-24 1999-08-17 Molex Incorporated Flat flexible cable with pseudo-twisted conductors
WO1998024141A1 (en) * 1996-11-26 1998-06-04 Raytheon Company Alignment tolerant overlay directional coupler
US5907266A (en) * 1996-11-26 1999-05-25 Raytheon Company Alignment tolerant overlay directional coupler
US6300846B1 (en) 1999-03-18 2001-10-09 Molex Incorporated Flat flexible cable with ground conductors
US20040160291A1 (en) * 2003-02-14 2004-08-19 Microlab/Fxr Microwave coupler
US20050146393A1 (en) * 2004-01-02 2005-07-07 Lu Chen High power directional coupler
US7049905B2 (en) * 2004-01-02 2006-05-23 Scientific Components Coporation High power directional coupler
US8044748B2 (en) * 2004-09-10 2011-10-25 Com-Tech S.R.L. Hybrid coupler and UHF television channel mixer comprising such a hybrid coupler
US20090033802A1 (en) * 2004-09-10 2009-02-05 Comtech S.R.L. Hybrid Coupler and UHF Television Channel Mixer Comprising Such a Hybrid Coupler
US8289656B1 (en) 2008-11-19 2012-10-16 Western Digital Technologies, Inc. Disk drive comprising stacked and stepped traces for improved transmission line performance
US20110051292A1 (en) * 2009-08-31 2011-03-03 Western Digital Technologies, Inc. Disk drive comprising impedance discontinuity compensation for interconnect transmission lines
US8462466B2 (en) 2009-08-31 2013-06-11 Western Digital Technologies, Inc. Disk drive comprising impedance discontinuity compensation for interconnect transmission lines
US8749989B1 (en) 2009-12-28 2014-06-10 Scientific Components Corporation Carrier for LTCC components
US8467151B1 (en) 2010-05-21 2013-06-18 Western Digital Technologies, Inc. Disk drive comprising an interconnect with transmission lines forming an approximated lattice network
US9240623B2 (en) 2011-04-11 2016-01-19 Lockheed Martin Corporation Wide-band microwave hybrid coupler with arbitrary phase shifts and power splits
EP2697861A4 (en) * 2011-04-11 2014-11-12 Lockheed Corp BROADBAND MICROWAVE HYBRID COUPLER WITH ANY PHASE SHIFT AND SPLIT POWER
US8879212B1 (en) 2013-08-23 2014-11-04 Western Digital Technologies, Inc. Disk drive suspension assembly with flexure having dual conductive layers with staggered traces
CN106165194A (zh) * 2014-03-20 2016-11-23 凯瑟雷恩工厂两合公司 多级的宽带定向耦合器
US20170141451A1 (en) * 2014-03-20 2017-05-18 Kathrein-Werke Kg Multi-stage broadband directional coupler
US10243249B2 (en) * 2014-03-20 2019-03-26 Kathrein Se Multi-stage broadband directional coupler
CN106165194B (zh) * 2014-03-20 2020-06-19 凯瑟雷恩欧洲股份公司 多级的宽带定向耦合器
US20170237140A1 (en) * 2016-02-17 2017-08-17 Eagantu Ltd. Wide band directional coupler
US10340577B2 (en) * 2016-02-17 2019-07-02 Eagantu Ltd. Wide band directional coupler
US20190067785A1 (en) * 2017-08-29 2019-02-28 Analog Devices, Inc. Broadband radio frequency coupler
US10826152B2 (en) * 2017-08-29 2020-11-03 Analog Devices, Inc. Broadband radio frequency coupler
US12004289B2 (en) * 2018-11-14 2024-06-04 Murata Manufacturing Co., Ltd. Flexible substrate and electronic device

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DE2041646C3 (de) 1980-08-28
FR2059694B1 (enrdf_load_stackoverflow) 1974-02-01
DE2041646A1 (de) 1971-03-11
GB1257906A (enrdf_load_stackoverflow) 1971-12-22
DE2041646B2 (de) 1979-12-20
FR2059694A1 (enrdf_load_stackoverflow) 1971-06-04

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