US3839688A - Directional filter - Google Patents

Directional filter Download PDF

Info

Publication number
US3839688A
US3839688A US00314518A US31451872A US3839688A US 3839688 A US3839688 A US 3839688A US 00314518 A US00314518 A US 00314518A US 31451872 A US31451872 A US 31451872A US 3839688 A US3839688 A US 3839688A
Authority
US
United States
Prior art keywords
coupling
resonator means
waveguide
resonator
primary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00314518A
Other languages
English (en)
Inventor
S Shimada
I Otomo
K Ohi
H Hirotani
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Telegraph and Telephone Corp
Kokusai Denki Electric Inc
Original Assignee
Nippon Telegraph and Telephone Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Application granted granted Critical
Publication of US3839688A publication Critical patent/US3839688A/en
Assigned to NIPPON TELEGRAPH & TELEPHONE CORPORATION reassignment NIPPON TELEGRAPH & TELEPHONE CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE ON 07/12/1985 Assignors: NIPPON TELEGRAPH AND TELEPHONE PUBLIC CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/213—Frequency-selective devices, e.g. filters combining or separating two or more different frequencies
    • H01P1/2138—Frequency-selective devices, e.g. filters combining or separating two or more different frequencies using hollow waveguide filters

Definitions

  • ABSTRACT A directional filter including a primary waveguide, a secondary waveguide, each of the waveguides having a rectangular cross-sectional area, resonator means having a circular cross-sectional area and opposite ends along which the primary and secondary waveguides are arranged respectively, the resonator means resonating at either transverse electric mode TE or transverse magnetic mode TM (N l, 2, a first directional coupler comprising at least two coupling elements distributed between the primary waveguide and one of the opposite ends of the resonator means for coupling the primary waveguide and the resonator means, and a second directional coupler comprising at least two coupling elements distributed between the secondary waveguide and the other of the opposite ends of the resonator means for coupling the secondary waveguide and the resonator means.
  • the present invention relates to a directional filter adapted to be used as a channel branching filter for microwave, quasi-millimeterwave and millimeterwave frequency bands.
  • FIG. 1 is a partially exploded perspective view of a conventional directional filter.
  • FIGS. 2A and 2B are diagrams showing partially exploded views of the resonator provided in the directional filter of FIG. 1.
  • FIG. 3 is a partially exploded perspective view showing an embodiment of the directional filter according to the present invention.
  • FIG. 4 is a perspective view showing another embodiment of the directional filter according to the present invention.
  • FIGS. 5A and 5B are partially exploded perspective views showing the resonator provided in the directional filter according to the present invention shown in FIGS. 3 and 4.
  • FIG. 6 is a diagram showing the frequency characteristics of the directional filter according to the present invention.
  • FIG. 7 is a partially exploded perspective view showing another embodiment of the directional filter according to the present invention.
  • a typical conventional directional filter for microwave, quasi-millimeterwave and millimeterwave frequency bands has a construction as shown in FIG. 1.
  • the directional filter includes a resonator 5' which, as shown in FIGS. 2A and 2B, comprises conductive cylinders' 1 and 2 arranged concentrically with each other and annular conductive end plates 3 and 4 extending from the one cylinder to the other cylinder.
  • the resonator 5 has an annular cross-sectional area and a main resonance frequency of f,,.
  • a primary waveguide 6' and a secondary waveguide 7' which have rectangular cross-sectional areas, are bent and folded in semicircular forms and extend in opposite directions are mounted on the end plates 3 and 4 of the resonator 5' in such a manner that the folded portions of face plates 8 and 9 of the primary and secondary waveguides are coupled with the end plates 3 and 4, respectively.
  • a plurality of coupling holes 10 acting as a directional coupler are bored through the end plate 3 of the resonator 5' and the adjoining face plate 8 of the primary waveguide 6' coupled with the end plate 3, while a plurality of coupling holes 11 acting as a directional coupler are formed through the end plate 4 of the resonator 5 and the adjoining face plate 9 of the secondary waveguide 7' coupled with the end plate 4.
  • That portions of the face plates 8 and 9 which are to be coupled with the end plates 3 and 4 may be doubled by' the end plates 3 and 4.
  • the length of the circumference of the circle having a radius equal to the average radius of the annular cross-sectional area of the resonator 5' is set at a value which is N times (N l, 2, as large as the wavelength in the resonator 5 corresponding to the frequency f
  • the resonator 5' has the resonance order of N but also has adjacent resonance frequenciesf andfou of the (N l)th and (N l)th orders respectively.
  • the diameter of the inner cylinder 2 must be made less than about 1 mm in the resonance fre quency of 50 Gl-lz and the resonance order of N 2 so that the integeral construction of the cylinder 2 and the end plates 3 and 4 becomes impossible. Also, even if individually prepared cylinder 2 and end plates 3 and 4 are constructed integrally it results in worse contact between the cylinder 2 and the end plates 3 and 4 and hence in increased thermal loss and lower Q of the resonator. Further, the small diameter of the cylinder 2 tends to contribute to the distortion thereof and hence to that generation of wave in the opposite direction which leads to worse directional action and lower VSWR (voltage standing-wave ratio).
  • the directional filter according to the present invention includes a primary waveguide, a secondary waveguide, each of said waveguides having arectangular cross-sectional area, resonator means having a circular cross-sectional area and opposite ends along which said primary and secondary waveguides are arranged respectively, said resonator means resonating at either transverse electric mode TE or transverse magnetic mode TM (N I, 2, a first directional coupler comprising at least two coupling elements distributed between said primary waveguide and one of the opposite ends of said resonator means for coupling said primary waveguide and said resonator means, and a second directional coupler comprising at least two coupling elements distributed between said secondary waveguide and the other of the opposite ends of said resonator means for coupling said secondary waveguide andsaid resonator means.
  • N I, 2 a first directional coupler comprising at least two coupling elements distributed between said primary waveguide and one of the opposite ends of said resonator means for coupling said primary waveguide and said resonator
  • the use of the resonator whose cross-sectional area is circular eliminates an inner conductive cylinder of the conventional directional filter comprising a resonator whose crosssectional area is annular, and enables the manufacturing of the resonator with higher accuracy, the higher mechanical stability of the resonator and the setting of the center frequency with higher accuracy.
  • a resonator 5 used in the directional filter according to the present invention comprises a conductive cylinder 17 having the ends thereof sealed with conductive end plates and 16 has a circular cross-sectional area.
  • a primary waveguide 6 and a secondary waveguide 7 which have rectangular cross-sectional areas, are bent and folded in semicircular forms and extend in opposite directions are arranged on the end plates 15 and 16 in such a manner that the folded portions of face plates 18 and 19 of the primary and secondary waveguides are coupled with the end plates 15 and 16, respectively.
  • the waveguide 6 has two ways which include a common face plate 20 and the waveguide 7 has two ways which include a common face plate 21, the common face plates 20 and 21 extending up to the central axis of the resonator 5 but in opposite directions to each other.
  • Face plates 32 and 33 of the waveguide 6 positioned opposite to the common face plate 20 and face plates 22 and 23 of the waveguide 7 positioned opposite to the common plate 21 are respectively bent in semicircular forms along the circumference of the cylinder 17 of the resonator 5.
  • a plurality of slits 24 which act as a directional coupler and extend radially about the center of the end plate 15 .of the resonator 5 are bored through both the end plate 15 and the face plate 18 of the primary waveguide 6 coupled therewith, while a plurality of slits 25 which act as a directional coupler and extend radially about the center of the end plate 16 of the resonator 5 are formed through both the end plate 16 and the face plate 19 of the secondary waveguide 7 coupled therewith.
  • the end plates 15 and 16 of the resonator 5 maydouble respectively as portions of the face plates 18 and 19 which are to be coupled with the end plates 15 and 16.
  • the same characteristics as those of the conventional directional filter are achieved by constructing the directional filter according to the present invention such that it comprises a'cylindrical resonator 5 which resonates under the transverse electric mode TE or transverse magnetic mode TM
  • the resonator according to the present invention has no restrictions as those to which the conventional resonator of FIGS. 1 and 2 are subjected, thus making it practicable to achieve the filter function without any reduction in unloaded O which otherwise might occur due to unsatisfactory contact of the inner cylinder.
  • curve 6 illustrates the transmission lossfrequency characteristics-of the directional filter employing the cylinder-shaped transverse magnetic resonance mode TM which characteristics were measured by the use of a sweep oscillator.
  • curve 38 shows transmission loss between the input end 26 and output end 27 of the waveguides
  • curve 36 shows transmission loss between the input 26 and output 28
  • curve 37 shows transmission loss between the output ends 27 and 28, the frequency band for transmission loss 3dB at the center frequency 51.05 GI-Iz .being 680 MHz and the transmission loss (or branch loss) between the input end 26 and output end 27 of the waveguides at the center frequency being 0.8dB which is almost identical with the characteristics of the conventional directional filter.
  • the directional filter according to the present invention may be constructed as illustrated in FIG. 4.
  • a primary waveguide 6a is coupled with the cylindrical resonator 5 with the transverse magnetic resonance mode TM through a directional coupler 24 comprising a plurality of slits
  • a secondary waveguide 7a is connected with the resonator 5 through a directional coupler comprising a plurality of slits distributed to the directional coupler 24 symmetrically with respect to the central axis of the resonator 5.
  • the waveguides 6a and 7a each has a straightline formation without any folded portion as in the preceding embodiment.
  • a tapered portion 35 curved in a circular arc form so as to pass through the central axis of the resonator 5 is provided for each waveguide at the central portion of the resonator 5, thus achieving the same filt'er function as the embodiment of FIG. 3.
  • the waveguides are coupled with the resonator having wider face plates to obtain transverse magnetic mode TM it is alternatively possible to obtain transverse electric mode TE by coupling the waveguides with the resonator having narrower face plates.
  • the single resonator used in the abovedescribed embodiments may be replaced by a plurality of resonators which are mounted on one another and are coupled with one another by means of directional couplers each comprising a plurality of coupling holes or slits.
  • Such a multi-stage arrangement of resonators may be made with higher mechanical stability because of the use of the resonators whose cross-sectional areas are not annular as in the conventional resonator but circular.
  • An example of a two-stage arrangement of resonators is shown in FIG. 7 in which resonators 5a and 5b are coupled with each other by a directional coupler comprising a plurality of coupling holes 39.
  • FIG. 7 similar reference numerals are used to designate components similar to those of FIG. 3.
  • a directional filter including a primary waveguide; a secondary waveguide, each of said waveguides having a rectangular cross-sectional area and a pair of wider faces plates and a pair of narrower face plates; resonator means having a circular cross-sectional area and opposite first and second circular end plates which have their radii substantially equal to the widths of said wider faces plates of said primary and secondary waveguides, a part of one of said wider faces plates of said primary waveguide and a part of one of said wider face plates of said secondary waveguide being coupled on and at least coextensive with at least a portion of said first end plate and at least a portion of said second end plate of said resonator means to form therein a first coupling area and a second coupling area, respectively, the direction of the center lines of said primary and secondary waveguides corresponding to the circumferential directions of said first and second end plates of said resonator means in said first andsecond coupling areas, respectively, said resonator means resonating at transverse magnetic mode TM (
  • a directional filter including a primary waveguide; a secondary waveguide, each of said waveguides having a rectangular cross-sectional area and a pair of wider face plates and a pair of narrower face plates; resonator means having a circular cross-sectional area and opposite first and second circular end plates which have their radii substantially equal to the widths of said narrower face plates of said primary and secondary waveguides, apart of one of said narrower face plate of said primary waveguide and a part of one of said narrower face plates of said secondary waveguide being coupled on and at least coextensive with at least a portion of said first end plate and at least a portion of said second end plate of said resonator means to form therein a first coupling area and a second coupling area, respectively,
  • a first directional coupler comprising a plurality of first coupling elements extending in said first coupling area radially about the center of said first end plate of said resonator means for coupling said primary waveguide and said resonator means; and a second directional coupler comprising a plurality of second coupling elements extending in said second coupling area radially about the center of said second end plate of said resonator means for coupling said secondary waveguide and said resonator means.

Landscapes

  • Control Of Motors That Do Not Use Commutators (AREA)
US00314518A 1971-12-15 1972-12-13 Directional filter Expired - Lifetime US3839688A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP46101012A JPS4866760A (enrdf_load_stackoverflow) 1971-12-15 1971-12-15

Publications (1)

Publication Number Publication Date
US3839688A true US3839688A (en) 1974-10-01

Family

ID=14289301

Family Applications (1)

Application Number Title Priority Date Filing Date
US00314518A Expired - Lifetime US3839688A (en) 1971-12-15 1972-12-13 Directional filter

Country Status (2)

Country Link
US (1) US3839688A (enrdf_load_stackoverflow)
JP (1) JPS4866760A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5930266A (en) * 1996-05-23 1999-07-27 Matra Marconi Space Uk Limited Multiplexing/demultiplexing an FDM of RF signal channels

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2936430A (en) * 1955-06-18 1960-05-10 Pierre G Marie Wide band resonant directional couplers
US2939093A (en) * 1955-06-30 1960-05-31 Pierre G Marie Directional channel separation filters
US3042883A (en) * 1953-07-24 1962-07-03 Philips Corp Frequency wave-filter

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3042883A (en) * 1953-07-24 1962-07-03 Philips Corp Frequency wave-filter
US2936430A (en) * 1955-06-18 1960-05-10 Pierre G Marie Wide band resonant directional couplers
US2939093A (en) * 1955-06-30 1960-05-31 Pierre G Marie Directional channel separation filters

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Matthaei et al., Microwave Filters, Impedance Matching Networks, and Coupling Structures, McGraw Hill, N.Y., 1964, TK3226M38, pp. 856 and 859 relied on. *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5930266A (en) * 1996-05-23 1999-07-27 Matra Marconi Space Uk Limited Multiplexing/demultiplexing an FDM of RF signal channels

Also Published As

Publication number Publication date
JPS4866760A (enrdf_load_stackoverflow) 1973-09-12

Similar Documents

Publication Publication Date Title
US4567401A (en) Wide-band distributed rf coupler
US6686815B1 (en) Microwave filter
US3899759A (en) Electric wave resonators
US5812036A (en) Dielectric filter having intrinsic inter-resonator coupling
CA1160700A (en) Strip-line resonator and a band pass filter having the same
US3995238A (en) Image waveguide transmission line and mode launchers utilizing same
US6556107B2 (en) Dielectric resonator, inductor, capacitor, dielectric filter, oscillator, and communication device
US4267537A (en) Right circular cylindrical sector cavity filter
JPH06326505A (ja) フレキシブル導波管
US4091343A (en) Insular waveguide directional coupler
US4138625A (en) Helix type travelling-wave tube amplifier
US4184130A (en) Filter devices incorporating dielectric resonators and leakage cable
US3668564A (en) Waveguide channel diplexer and mode transducer
US4185257A (en) Quasioptical band rejection filter
US4048589A (en) Receiver module and components thereof
US3144624A (en) Coaxial wave filter
US3611214A (en) Waveguide reflective harmonic filter
US6201456B1 (en) Dielectric filter, dielectric duplexer, and communication device, with non-electrode coupling parts
US3839688A (en) Directional filter
US4072902A (en) Receiver module and mixer thereof
CA2134386C (en) Biconical multimode resonator
US7274273B2 (en) Dielectric resonator device, dielectric filter, duplexer, and high-frequency communication apparatus
US3600711A (en) Coaxial filter having harmonic reflective and absorptive means
CA1222550A (en) Microwave push-pull frequency converter
US6249195B1 (en) Dielectric filter, dielectric duplexer, and transceiver having circular and polygonal electrode openings

Legal Events

Date Code Title Description
AS Assignment

Owner name: NIPPON TELEGRAPH & TELEPHONE CORPORATION

Free format text: CHANGE OF NAME;ASSIGNOR:NIPPON TELEGRAPH AND TELEPHONE PUBLIC CORPORATION;REEL/FRAME:004454/0001

Effective date: 19850718

STCF Information on status: patent grant

Free format text: PATENTED FILE - (OLD CASE ADDED FOR FILE TRACKING PURPOSES)