US3748601A - Coupling networks having broader bandwidth than included phase shifters - Google Patents

Coupling networks having broader bandwidth than included phase shifters Download PDF

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Publication number
US3748601A
US3748601A US00208305A US3748601DA US3748601A US 3748601 A US3748601 A US 3748601A US 00208305 A US00208305 A US 00208305A US 3748601D A US3748601D A US 3748601DA US 3748601 A US3748601 A US 3748601A
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band
interest
phase shift
over
coupler
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Expired - Lifetime
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US00208305A
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English (en)
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H Seidel
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AT&T Corp
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Bell Telephone Laboratories Inc
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/38—Impedance-matching networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/18—Networks for phase shifting
    • H03H7/21—Networks for phase shifting providing two or more phase shifted output signals, e.g. n-phase output

Definitions

  • the obtainable passband can be further extended by means of a boot-strapping arrangement wherein two such networks are used to obtain a broader band 180 phase shifter.
  • the desired 180 of phase shift for one of the two networks is obtained by means of a high frequency, 1:1 turns ratio transformer located in the interconnecting wavepath that carries the higher frequency signal components. While this transformer is essentially ineffectual at the lower frequencies of inter est, essentially no signals at these frequencies are coupled through this wavepath.
  • a broadband impedance transformer can be realized using two, band limited transformers interconnecting two identical hybrid couplers.
  • FIG. 3 shows an alternate embodiment of the invention
  • FIG. 6 shows a broadband transformer in accordance with the present invention.
  • each of the couplers has four branches 1, 2, 3 and 4, and 1', 2, 3' and 4', arranged in pairs 1-2 and 2-4, and l-2' and 3'4', where the branches of each pair are conjugate to each other and in coupling relationship with branches of the other of said pair.
  • a first coupling coefficient t defines the coupling between branches l-3, 2-4, l'-3' and 2'4'
  • a second coupling coefficient It defines the coupling between branches l-4, 2-3, 1'4 and 2'-3'. While these are generally complex quantities whose magnitudes and phases vary as a function of frequency, they are related, at all frequencies such that In addition, the coupled signals bear some fixed relative phase relationship, depending upon the nature of the coupler.
  • the t signal at branch 3 undergoes a 180 phase shift as it traverses wavepath 12, and appears as a t signal at branch 3 of coupler 11.
  • Signal ik experiences no relative phase shift along wavepath 13, appearing as a signal ik at coupler branch 4. Since the two couplers are identical, signal t produces a signal component -t at branch I and a signal component ikt at branch 2'. Simultaneously, signal ik, in turn, produces a signal component (ik) equal to ---k at branch I, and a signal component +ikt at branch 2'. Adding the signal components at the respective branches we obtain for branch I and for branch 2 ikt ikt 0.
  • the circuit illustrated in FIG. 1 is an all-pass network. However, it is an all-pass network only over the frequency band for which the phase shifter provides 180 of phase shift. For relatively narrowband applications, this is generally not a problem. The difficulty resides in extending the passband. The problem is that a transformer designed to operate well at the lower end of an extended band of frequencies, will generally not function well at the higher end because of parasitics which convert the simple transformer to a more complex network having a different phase shift. In addition, the core materials which are needed at the lower frequen cies are generally lossy at the higher frequencies. Conversely, a transformer designed to operate at the higher frequencies will, because of inadequate core reactance, not operate well at the lower frequencies.
  • a low frequency transformer was placed in the circuit of the network.
  • a high frequency transformer can be placed in the k circuit of the network.
  • FIG. 3 This embodiment is in all respects identical to the embodiment of FIG. I with the exception that a phase shifter 14' is located in wavepath 13 between coupler branches 4 and 4. If, as previously, a unit signal is applied to input branch I, it can readily be shown that a unit output signal +1 is obtained at output branch 1. Since branch 13 is the k signal branch, from FIG.
  • the k signal is negligibly small over the lower portion of the band of interest and, hence, all-pass operation between frequencies f, and f, can be realized using a high frequency transformer designed to operate over the band of frequencies from f to f,,.
  • a low frequency, band-limited 180 phase shifter in the t signal path, or a high frequency, band-limited 180 phase shifter in the k signal path results in networks having all-pass characteristics that are greater than the bandwidth of either phase shifter. Obviously, this greatly reduces the problems incidental to the design of very broadband all-pass networks of the type described.
  • FIG. 4 illustrates the use of two all-pass networks 30 and 31 to generate two out-of-phase signals.
  • Network 30, of the type illustrated in FIG. 1 comprises two cascaded hybrid couplers 40 and 41, including a low frequency 180 phase shifter 42 located in the t signal wavepath connecting couplers 40 and 41.
  • Network 31, of the type illustrated in FIG. 3 comprises two cascaded hybrid couplers 43 and 44, including a high frequency 180 phase shifter 45 located in the k signal wavepath connecting couplers 43 and 44.
  • all-pass networks 54 and 55 were such that the t signal underwent l80 of relative phase shift.
  • the circuit can, alternatively, be arranged so that the k signal is shifted 180, in which case an output signal of 1 LOis produced.
  • two such broadband all-pass networks can be used, as explained in connection with FIG. 4, to produce a broader band l80relative phase shifter.
  • a network having an all'pass transmission characteristic over a specified frequency band of interest AF comprising:
  • the coupling coefficient k is significant over the upper portion of said band of interest and is negligibly small at the lower end of said band of interest;
  • phase shift means introduces 180 of relative phase shift over a portion of said band of interest that is at least coextensive with the portion of said band for which the coupling between the wavepath wherein said means is located and said input and output ports is significant, but less than said band of interest.
  • phase shift means is a 1:1 turns ratio transformer located in said second wavepath
  • a phase shifter for introducing 180 of relative phase shift between signals in two transmission paths comprising:
  • phase shift means is a 1:1 turns ratio transformer located in said first wavepath for providing 180 of phase shift over the portion of said band for which coupling coefficient t is significant;
  • phase shift means is a 1:1 turns ratio transformer located in said second wavepath for providing 180 of phase shift over the portion of said band for which coupling coefficient k is significant.
  • a circuit having an all-pass transmission characteristic over a specified frequency band of interest AF comprising:
  • said coefficient t being significant over the lower portion of said band of interest AF, and negligibly small at the upper end of said band of interest AF;
  • said coefficient k being significant over the upper portion of said band of interest AF, and negligibly small at the lower end of said band of interest AF;
  • said second network has an all-pass characteristic over a frequency band of interest that is at least coextensive with the portion of said band of interest AF for which the coupling between the signal path wherein said second network is located and said input and output ports is significant, but less than said band of interest AF.
  • one branch of one pair of conjugate branches of one coupler being the input port of said transformer

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  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Coils Or Transformers For Communication (AREA)
US00208305A 1971-12-15 1971-12-15 Coupling networks having broader bandwidth than included phase shifters Expired - Lifetime US3748601A (en)

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US20830571A 1971-12-15 1971-12-15

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US (1) US3748601A (de)
JP (1) JPS4866955A (de)
AU (1) AU471293B2 (de)
BE (1) BE792560A (de)
CA (1) CA944445A (de)
DE (1) DE2261082A1 (de)
FR (1) FR2163631B1 (de)
GB (1) GB1388318A (de)
IT (1) IT974047B (de)
NL (1) NL7216909A (de)
SE (1) SE377247B (de)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3988705A (en) * 1975-11-20 1976-10-26 Rockwell International Corporation Balanced four-way power divider employing 3db, 90° couplers
US4394629A (en) * 1981-03-31 1983-07-19 Rca Corporation Hybrid power divider/combiner circuit
US4906954A (en) * 1987-05-29 1990-03-06 Atr Optical And Radio Communications Research Laboratories Directional coupler device
US5063365A (en) * 1988-08-25 1991-11-05 Merrimac Industries, Inc. Microwave stripline circuitry
US5376904A (en) * 1993-05-20 1994-12-27 Northern Telecom Limited Directional coupler for differentially driven twisted line
EP0678979A2 (de) * 1994-04-20 1995-10-25 AT&T Corp. Koppler für Übertragungssysteme mit mehreren Frequenzbändern
US20050122186A1 (en) * 2003-12-08 2005-06-09 Podell Allen F. Phase inverter and coupler assembly
US20060066418A1 (en) * 2003-06-25 2006-03-30 Werlatone, Inc. Multi-section coupler assembly
US20080143456A1 (en) * 2006-12-15 2008-06-19 Isotek Electronics Limited Band combining filter
US20100205233A1 (en) * 2009-02-09 2010-08-12 Matthew Alexander Morgan Reflectionless filters
US20130115897A1 (en) * 2011-11-08 2013-05-09 Filtronic Wireless Limited Filter block and a signal transceiver comprising such a filter block
US20150244441A1 (en) * 2011-03-01 2015-08-27 Silicon Image, Inc. Tracking system with orthogonal polarizations and a retro-directive array
US9705467B2 (en) 2014-06-25 2017-07-11 Assoicated Universties, Inc. Sub-network enhanced reflectionless filter topology
US9923540B2 (en) 2014-11-05 2018-03-20 Associated Universities, Inc. Transmission line reflectionless filters
US10263592B2 (en) 2015-10-30 2019-04-16 Associated Universities, Inc. Optimal response reflectionless filters
US10374577B2 (en) 2015-10-30 2019-08-06 Associated Universities, Inc. Optimal response reflectionless filters
US10530321B2 (en) 2015-10-30 2020-01-07 Associated Universities, Inc. Deep rejection reflectionless filters

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3037175A (en) * 1958-05-12 1962-05-29 Bell Telephone Labor Inc Broadband transformers
US3444475A (en) * 1967-04-19 1969-05-13 Bell Telephone Labor Inc Broadband hybrid-coupled circuit
US3514722A (en) * 1965-08-11 1970-05-26 Merrimac Research & Dev Inc Networks using cascaded quadrature couplers,each coupler having a different center operating frequency

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3231837A (en) * 1961-06-20 1966-01-25 Hughes Aircraft Co All-pass transformer coupling network utilizing high frequency and low frequency transformers in parallel connection
DE1947889C3 (de) * 1969-09-22 1975-04-17 Siemens Ag, 1000 Berlin Und 8000 Muenchen Weichennetzwerk, bestehend aus einem Weichenallpaß

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3037175A (en) * 1958-05-12 1962-05-29 Bell Telephone Labor Inc Broadband transformers
US3514722A (en) * 1965-08-11 1970-05-26 Merrimac Research & Dev Inc Networks using cascaded quadrature couplers,each coupler having a different center operating frequency
US3444475A (en) * 1967-04-19 1969-05-13 Bell Telephone Labor Inc Broadband hybrid-coupled circuit

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3988705A (en) * 1975-11-20 1976-10-26 Rockwell International Corporation Balanced four-way power divider employing 3db, 90° couplers
US4394629A (en) * 1981-03-31 1983-07-19 Rca Corporation Hybrid power divider/combiner circuit
US4906954A (en) * 1987-05-29 1990-03-06 Atr Optical And Radio Communications Research Laboratories Directional coupler device
US5063365A (en) * 1988-08-25 1991-11-05 Merrimac Industries, Inc. Microwave stripline circuitry
US5376904A (en) * 1993-05-20 1994-12-27 Northern Telecom Limited Directional coupler for differentially driven twisted line
EP0678979A3 (de) * 1994-04-20 1996-09-11 At & T Corp Koppler für Übertragungssysteme mit mehreren Frequenzbändern.
EP0678979A2 (de) * 1994-04-20 1995-10-25 AT&T Corp. Koppler für Übertragungssysteme mit mehreren Frequenzbändern
US20060066418A1 (en) * 2003-06-25 2006-03-30 Werlatone, Inc. Multi-section coupler assembly
US7190240B2 (en) 2003-06-25 2007-03-13 Werlatone, Inc. Multi-section coupler assembly
US20070159268A1 (en) * 2003-06-25 2007-07-12 Werlatone, Inc. Multi-section coupler assembly
US7345557B2 (en) 2003-06-25 2008-03-18 Werlatone, Inc. Multi-section coupler assembly
US20050122186A1 (en) * 2003-12-08 2005-06-09 Podell Allen F. Phase inverter and coupler assembly
US7042309B2 (en) 2003-12-08 2006-05-09 Werlatone, Inc. Phase inverter and coupler assembly
US20080143456A1 (en) * 2006-12-15 2008-06-19 Isotek Electronics Limited Band combining filter
US20100205233A1 (en) * 2009-02-09 2010-08-12 Matthew Alexander Morgan Reflectionless filters
US8392495B2 (en) * 2009-02-09 2013-03-05 Associated Universities, Inc. Reflectionless filters
US20150244441A1 (en) * 2011-03-01 2015-08-27 Silicon Image, Inc. Tracking system with orthogonal polarizations and a retro-directive array
US9306647B2 (en) * 2011-03-01 2016-04-05 Lattice Semiconductor Corporation Tracking system with orthogonal polarizations and a retro-directive array
US20130115897A1 (en) * 2011-11-08 2013-05-09 Filtronic Wireless Limited Filter block and a signal transceiver comprising such a filter block
US9130653B2 (en) * 2011-11-08 2015-09-08 Filtronic Wireless Limited Filter block and a signal transceiver comprising such a filter block
US10230348B2 (en) 2014-06-25 2019-03-12 Associated Universities, Inc. Sub-network enhanced reflectionless filter topology
US9705467B2 (en) 2014-06-25 2017-07-11 Assoicated Universties, Inc. Sub-network enhanced reflectionless filter topology
US9923540B2 (en) 2014-11-05 2018-03-20 Associated Universities, Inc. Transmission line reflectionless filters
US10277189B2 (en) 2014-11-05 2019-04-30 Associated Universities, Inc. Transmission line reflectionless filters
US10263592B2 (en) 2015-10-30 2019-04-16 Associated Universities, Inc. Optimal response reflectionless filters
US10374577B2 (en) 2015-10-30 2019-08-06 Associated Universities, Inc. Optimal response reflectionless filters
US10516378B2 (en) 2015-10-30 2019-12-24 Associated Universities, Inc. Optimal response reflectionless filter topologies
US10530321B2 (en) 2015-10-30 2020-01-07 Associated Universities, Inc. Deep rejection reflectionless filters

Also Published As

Publication number Publication date
AU471293B2 (en) 1976-04-15
GB1388318A (en) 1975-03-26
IT974047B (it) 1974-06-20
JPS4866955A (de) 1973-09-13
CA944445A (en) 1974-03-26
FR2163631B1 (de) 1975-09-12
DE2261082A1 (de) 1973-06-20
NL7216909A (de) 1973-06-19
SE377247B (de) 1975-06-23
FR2163631A1 (de) 1973-07-27
BE792560A (fr) 1973-03-30
AU4992672A (en) 1974-06-13

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