US3593210A - Waveguide junction circulator wherein all modes in each branch arm are evanescent - Google Patents

Waveguide junction circulator wherein all modes in each branch arm are evanescent Download PDF

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Publication number
US3593210A
US3593210A US886639A US3593210DA US3593210A US 3593210 A US3593210 A US 3593210A US 886639 A US886639 A US 886639A US 3593210D A US3593210D A US 3593210DA US 3593210 A US3593210 A US 3593210A
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waveguide
section
junction circulator
port
circulator
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US886639A
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English (en)
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Richard Finnle Skedd
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STC PLC
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International Standard Electric Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/32—Non-reciprocal transmission devices
    • H01P1/38—Circulators
    • H01P1/383—Junction circulators, e.g. Y-circulators
    • H01P1/39—Hollow waveguide circulators

Definitions

  • ELEC- ABSTRACT A waveguide junction circulator of the type having a resonant cavity loaded with ferrimagnetic material wherein the coupling ports consist of a length of waveguide having a cutoff frequency which is higher than the operating frequency and wherein said waveguide is tuned to the operating frequency by inserting therein, along the broad wall at predetermined lengths, screws whose capacitive reactance is equal to the conjugate of the imaginary characteristic impedance of the waveguide.
  • the cutolf frequency of the rectangular waveguide is made tunable and the resulting passband variable by inserting in said waveguide, along the sidewalls, ferrimagnetic strips and subjecting said strips to a variable magnetic field.
  • a waveguide junction circulator of the type having a resonant cavity loaded with a ferrimagnetic material, a source of a magnetic field, and a plurality of ports coupled to said cavity wherein at least one of said ports comprises at least one section of waveguide having a cutoff frequency above the resonant frequency of said cavity and means for terminating said section length of waveguide with a reactance whose value is equal to the conjugate of the imaginary characteristic impedance of each section length of waveguide.
  • FIG. I shows a three-port waveguide junction circulator with ports of rectangular cross section
  • FIG. 2 is a transmission line equivalent circuit of a section of one port of the circulator of FIG. I in respect of evanescent H waves,
  • FIG. 3 is a lumped circuit equivalent of the section
  • FIG. 4 shows the performance of a junction circulator as shown in FIG. 1,
  • FIG. 5 shows a three-port waveguide junction circulator with ports of rectangular cross section loaded with ferrimagnetic material
  • FIG. 6 shows effective permeability vs. angular frequency for transversely magnetized ferrite
  • FIG. 7 shows a section of waveguide loaded with ferrimagnetic sidewall strips
  • FIG. 8 shows insertion loss vs. frequency for a ferrite loaded section of waveguide in cutoff condition with DC magnetic field as a parameter.
  • FIG. I shows a three-port junction circulator with a central resonant cavity I containing ferrimagnetic material 2.
  • the ferrimagnetic material 2 is subjected to a DC magnetic field H m in. the direction indicated to obtain circulation in an anticloclrwise direction.
  • Each port 4 consists of a length 5 of rectangular cross section waveguide of length 21 with two adjustable capacitive screws 6 and 7 on the longitudinal centerline of the upper broad wall of the waveguide.
  • the Iongitu' dinal spacing between the screws 6 and 7 being I (each screw being at a distance of [/2 from the center point of the length) with each screw extending into its respective waveguide.
  • each length 5 has typically a height of 0.4 ins. and a width of 0.9 ins.
  • a waveguide at frequencies below cutoff exhibits characteristics common to all nondissipative filter networks in their stopband region.
  • the characteristic impedance which is real In the passband becomes imaginary in the stopband.
  • the propagation constant which is imaginary in the passband becomes real in the stopband.
  • the transmission line analog of a section of length I of the input port 4 is shown in FIG. 2 as a line of length I having a positive imaginary characteristic impedance jZ and a real propagation constant y To evanescent H waves therefore the length 1 looks like a pure inductance.
  • the lumped circuit equivalent of FIG. 2 is shown in FIG. 3 as a rr equivalent circuit giving the inductance reactance values as functions of 2 y, and I.
  • the section of waveguide is terminated in a capacitance C such that the capacitive reactance X is the conjugate of the inductive reactance of the section, there will be full energy transfer through the section.
  • the energy transfer is frequency sensitive and the section behaves as a bandpass filter.
  • the passband frequency limits (I, andfz) are given by:
  • the center frequency, f occurs at the geometric mean Therefore
  • the bandwidth is a function of y, and (in the ideal lossless case) as 7,! approaches a due to 1 then tanh ,1 coth ,1, and the bandwidth (frf reduces towards zero.
  • the inlet port therefore behaves as a two section band-pass filter, in which the required value for each section capacitance to provide conjugate matching with the inductance of the respective section is provided by suitably adjusting the capacitive screws 6 and 7 of the inlet port.
  • FIG. 4 shows the performance of a waveguide junction circulator as shown in FIG. I, having ports of rectangular cross section with internal dimensions of 0.622 ins. X 0.40 ins., capacitive screws 8 B.A., and a ferrite cylinder 0.32 ins. diameter X 0.40ins.
  • the general functioning of the circulator is conventional, in permitting energy transfer from one port to an adjacent port only in the direction of rotation determined by the magnetic field applied to the ferrimagnetic material.
  • Application of the circulator is also conventional such as coupling one port to an aerial, one port to a microwave radio transmitter, and one port to a microwave radio receiver.
  • Energy propagation external to the circulator ports may be by propagating waveguide, in which case a further capacitive matching screw will be required at each junction between the evanescent waveguide and the larger dimensioned propagating waveguide.
  • the circulator may be coupled into a microwave system constructed entirely in evanescent waveguide.
  • FIG 5 shows another form of three-port junction circulator, with the same reference numerals as in FIG. I used to indicate like elements.
  • each port behaves as a two section evanescent waveguide band-pass filter tor full energy transmission therethrough at the operating frequency.
  • Each port 4 is constructed of waveguide having height and. width dimensions such as to be propagating at the operating frequency.
  • Each port contains loading strips 8 of ferrirnagnetic material, such as ferrite or garnet, symmetrically ar-- ranged one at each sidewall of the waveguide.
  • the ferrimagnetic material strips 8 are subjected to a DC magnetic field m,-
  • the cutoff frequency may be controlled by the DC magnetic field.
  • the cutoff frequency can be made higher or lower than the empty waveguide value.
  • m is the cutoff frequency and w, the gyromagnetic resonance for the infinite ferrite medium.
  • each port ofthe circulator of FIG. 5 the length of waveguide is in the evanescent condition brought about as explained above by the DC magnetic field.
  • This condition is illustrated in H6. 8 and also shows how the cutoff frequency of each port is dependent on the value of DC magnetic field.
  • the field may be made variable in value when applied by per manent magnet pole pieces by arranging for the pole pieces to be movable, and when applied by electromagnetic pole pieces by varying the current.
  • Each port is tunable in frequency by variation in the value of the DC magnetic field. An increase in field raises the frequency, and a reduction in field lowers the frequency.
  • the junction circulator is frequency variable.
  • the junction circulator may alternatively be constructed with ports of waveguide lengths having square or circular cross section.
  • each port may have one, three or more sections each containing a single capacitive screw.
  • the capacitive screw or screws in each section of the ports may be replaced by other forms of capacitive obstacle, such as adjustable capacitive diaphragms.
  • junction circulators olTer a fundamentally broader frequency band capability than conventional (dispen sive) waveguide junction circulators because of the lumped element nature of the evanescent mode ports.
  • a junction circulator having three ports, each port comprising two contiguous section lengths of waveguide having a cutoff frequency above the resonant frequency of said waveguide and wherein said means for terminating each section length includes one or more capacitive screws mounted on one broad wall of each section length of waveguide.
  • a junction circulator according to claim I, wherein said at least one section length of waveguide includes a waveguide loaded with ferrimagnetic material.
  • a junction circulator according to claim 3, wherein said waveguide is symmetrically loaded with ferrimagnetic material on each sidewall.
  • a junction circulator having three ports, each port comprising two contiguous section lengths of waveguide and wherein said means for terminating each section length includes one or more capacitive screws mounted on one broad wall of each section length of waveguide.

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US886639A 1969-03-05 1969-12-19 Waveguide junction circulator wherein all modes in each branch arm are evanescent Expired - Lifetime US3593210A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB01783/69A GB1190547A (en) 1969-03-05 1969-03-05 Improvements in Electrical Waveguide Arrangements

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US3593210A true US3593210A (en) 1971-07-13

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US (1) US3593210A (enrdf_load_stackoverflow)
CH (1) CH515625A (enrdf_load_stackoverflow)
DE (1) DE2008584A1 (enrdf_load_stackoverflow)
FR (1) FR2034666B1 (enrdf_load_stackoverflow)
GB (1) GB1190547A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5769302U (enrdf_load_stackoverflow) * 1980-10-16 1982-04-26
US5184097A (en) * 1990-02-23 1993-02-02 Alcatel Transmission Par Faisceaux Hertziens Agile microwave filter having at least one ferrite resonator
EP1425816B1 (en) * 2001-09-14 2011-07-27 Andrew Limited Electromagnetic control devices
CN105659315A (zh) * 2013-08-21 2016-06-08 德克萨斯大学系统董事会 基于线性或者角动量偏置的非互易式声学装置
US9520633B2 (en) 2014-03-24 2016-12-13 Apollo Microwaves Ltd. Waveguide circulator configuration and method of using same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4433064C1 (de) * 1994-09-16 1995-10-19 Ant Nachrichtentech Anordnung zur Impedanzanpassung für nichtreziproke Bauelemente

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3492601A (en) * 1967-12-21 1970-01-27 Bell Telephone Labor Inc Three port e-plane waveguide circulator

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH336876A (de) * 1954-11-19 1959-03-15 Philips Nv Einseitig durchlässiges Übertragungssystem für elektromagnetische Wellen
US2972122A (en) * 1958-04-25 1961-02-14 Bell Telephone Labor Inc Nonreciprocal wave transmission
FR1279788A (fr) * 1960-02-03 1961-12-22 Western Electric Co Dispositif non réciproque pour ondes ultra-courtes
US3165711A (en) * 1960-06-10 1965-01-12 Bendix Corp Anisotropic circulator with dielectric posts adjacent the strip line providing discontinuity for minimizing reflections
FR1299945A (fr) * 1960-09-10 1962-07-27 Philips Nv Isolateur directif à résonance
NL303018A (enrdf_load_stackoverflow) * 1963-12-31 1965-10-25
US3286201A (en) * 1966-04-29 1966-11-15 Melabs Ferrite circulator having three mutually coupled coils coupled to the ferrite material

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3492601A (en) * 1967-12-21 1970-01-27 Bell Telephone Labor Inc Three port e-plane waveguide circulator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Chait et al. New Microwave Circulators, ELECTRONICS, Dec. 18, 1959 333-1.1 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5769302U (enrdf_load_stackoverflow) * 1980-10-16 1982-04-26
US5184097A (en) * 1990-02-23 1993-02-02 Alcatel Transmission Par Faisceaux Hertziens Agile microwave filter having at least one ferrite resonator
EP1425816B1 (en) * 2001-09-14 2011-07-27 Andrew Limited Electromagnetic control devices
CN105659315A (zh) * 2013-08-21 2016-06-08 德克萨斯大学系统董事会 基于线性或者角动量偏置的非互易式声学装置
US9520633B2 (en) 2014-03-24 2016-12-13 Apollo Microwaves Ltd. Waveguide circulator configuration and method of using same

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Publication number Publication date
CH515625A (de) 1971-11-15
FR2034666A1 (enrdf_load_stackoverflow) 1970-12-11
DE2008584A1 (de) 1971-02-11
GB1190547A (en) 1970-05-06
FR2034666B1 (enrdf_load_stackoverflow) 1974-05-03

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Effective date: 19870423

Owner name: STC PLC, 10 MALTRAVERS STREET, LONDON, WC2R 3HA, E

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:INTERNATIONAL STANDARD ELECTRIC CORPORATION, A DE CORP.;REEL/FRAME:004761/0721

Effective date: 19870423