EP0430136A1 - Bandsperrfilter für Mikrowellenhohlleiter - Google Patents

Bandsperrfilter für Mikrowellenhohlleiter Download PDF

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Publication number
EP0430136A1
EP0430136A1 EP90122545A EP90122545A EP0430136A1 EP 0430136 A1 EP0430136 A1 EP 0430136A1 EP 90122545 A EP90122545 A EP 90122545A EP 90122545 A EP90122545 A EP 90122545A EP 0430136 A1 EP0430136 A1 EP 0430136A1
Authority
EP
European Patent Office
Prior art keywords
short
waveguide
coaxial line
screw
conductor
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.)
Ceased
Application number
EP90122545A
Other languages
English (en)
French (fr)
Inventor
Jean-Claude Cruchon
Jean-Denis Schubert
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.)
Alcatel CIT SA
Original Assignee
Alcatel Telspace SA
Alcatel Transmission par Faisceaux Hertziens SA
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 Alcatel Telspace SA, Alcatel Transmission par Faisceaux Hertziens SA filed Critical Alcatel Telspace SA
Publication of EP0430136A1 publication Critical patent/EP0430136A1/de
Ceased legal-status Critical Current

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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
    • H01P1/207—Hollow waveguide filters
    • H01P1/209—Hollow waveguide filters comprising one or more branching arms or cavities wholly outside the main waveguide

Definitions

  • the invention relates to a band eliminator filter for microwave waveguides.
  • a microwave transmission system it is often necessary to weaken one frequency band without weakening another neighboring frequency band.
  • the separation of the transmitted and received waves is ensured by a frequency difference and by a crossover of the polarizations, but it is nevertheless necessary to attenuate the transmitted waves arriving on the receiver. , to avoid phenomena of saturation, undesirable beats, etc ...
  • a band eliminator filter consisting of at least one resonant cavity coupled to a waveguide by an iris. To sufficiently attenuate the frequency band to be eliminated, it is conventional to multiply the number of cavities coupled to the guide section. These cavities are separated by an odd number of quarters of the wavelength corresponding to the central frequency of the band to be passed without attenuation.
  • the guide has a rectangular section, the cavities are arranged on at least one of the long sides of the guide, and optionally on both sides, to multiply the number of cavities while minimizing the bulk.
  • this type of band eliminator filter is very bulky and expensive. It is therefore particularly ill-suited for producing stations with low capacity, which must have a low cost, and in which it is desirable to integrate in a single housing the transmission device and the microwave reception device.
  • the object of the invention is to propose a band eliminator filter for waveguides, the production of which is inexpensive and the space requirement of which is small enough to allow its integration into a transmitting / receiving head of a station. at low capacity.
  • the object of the invention is a band eliminator filter comprising at least one resonator consisting of an element with inductive susceptance and a capacitive susceptance element, compact and easy to produce, the first being consisting of a short-circuited coaxial line, and the second consisting of a short conductor plunging into the waveguide, and which extends the central conductor of the line.
  • the inner conductor comprises a metal screw, screwed into the threaded hole; this screw comprising a cylindrical extension having the same axis of symmetry of revolution as the screw but having a smaller diameter.
  • the part of the threaded hole which is not occupied by the screw constitutes an external conductor for the coaxial line, while the extension of the screw constitutes an internal conductor, and that the screw itself constitutes a short circuit to the end of the coaxial line.
  • This embodiment is very simple, since it suffices to modify a conventional brass screw, by removing metal by means of a lathe, to constitute an extension having a length equal to an odd multiple of a quarter of the wavelength corresponding to the center frequency of the band to be eliminated.
  • the short-circuited coaxial line comprises an externally threaded cylindrical sleeve, internally smooth, closed at one end by a conducting plane constituting a short-circuit and carrying a coaxial cylindrical conductor constituting the inner conductor.
  • the socket is screwed into the threaded hole.
  • This embodiment is slightly more complex since such a socket cannot be produced by modifying a screw. On the other hand, it has the advantage of allowing the use of a waveguide section having thinner walls.
  • the two embodiments have the advantage of being much less expensive and much less bulky than conventional filters, for a given number of resonators.
  • FIG. 1 schematically represents a known example of realization of an adjustable capacitive susceptance. It comprises a waveguide 1 in which a metal screw 2 is inserted which is screwed into a threaded hole 5 situated in the plane of symmetry of the section of the guide 1.
  • the screw 2 comprises a slot 3 allowing it to be screwed or the unscrew to adjust the recess, so that the end 6 of the screw slightly protrudes inside the waveguide 1.
  • the value of the susceptance is adjusted by screwing or unscrewing the screw 2, then this ci is immobilized by means of a nut 4 screwed on the screw 2 and tightened against the external surface of the waveguide.
  • a coaxial line short-circuited at one end has, at the other end, an inductive susceptance when the length l of the line is less than a quarter of the wavelength ⁇ or slightly less than an odd multiple of a quarter of the wavelength.
  • FIG. 2 schematically represents a short-circuited coaxial line comprising an inner conductor 7 and an outer conductor 8 each having a cylindrical shape with a circular section.
  • the short circuit is constituted by a metallic plane 9 connecting the conductors 7 and 8 to one end of the line.
  • the susceptance of this line is adjustable by varying the length of the line.
  • the invention consisted in combining these two known means to constitute a resonator eliminating a frequency band.
  • these means cannot be combined in any way, otherwise there is a significant disturbance in the propagation of the frequencies to be passed.
  • Figures 3 and 4 show a first embodiment of the filter according to the invention, comprising a single resonator and a waveguide with rectangular section.
  • a short-circuited coaxial line is constituted by a threaded hole 19 and by a screw 12 which is shown in section in FIG. 4.
  • the hole 19 is drilled in the longest side of the guide 11, in the plane of symmetry of the latter. this.
  • the screw 12 comprises: a slot 13 for screwing it in or out screw in using a screwdriver; a threaded part 14 provided with a thread 15 corresponding to the thread of the hole 19, and a smooth part 17 having a cylindrical shape with circular section having the same axis of symmetry YY 'as the part 14, and extending the latter.
  • Part 17 has a length equal to an odd multiple of a quarter of the wavelength corresponding to the center frequency of the frequency band to be eliminated. In this example, it is exactly one quarter wavelength.
  • Part 17 constitutes the inner conductor of a coaxial line with circular section, and constitutes a bar plunging into the guide 11.
  • the outer conductor of the coaxial line consists of the threaded hole 19, in the part not occupied by the screw 12
  • the length of the unoccupied part of the threaded hole 19 is slightly less than a quarter of a length and has an inductive susceptance.
  • a shoulder 16 constitutes a conducting plane short-circuiting the end of the coaxial line.
  • the length of the external conductor of this line is adjusted by screwing or unscrewing the screw 12. The adjustment is such that the length of the line is slightly less than a quarter of a wavelength, therefore a portion of part 17 exceeds inside the guide 11 and has a capacitive susceptance, the value of which also depends on the position of the screw 12.
  • a nut 18 is screwed onto the screw 12, and is tightened on the external surface of the wave guide, to immobilize screw 12 after it has been adjusted.
  • the guide 11 can be produced in a very conventional manner by extruding an aluminum alloy.
  • the thickness of the wall must be sufficient so that the unoccupied part of the threaded hole 19 can have a length close to a quarter of the wavelength corresponding to the central frequency of the strip to be eliminated.
  • the screw 12 can be produced by machining a conventional screw made of brass, to reduce its diameter over part of its length and form a shoulder 16. It may possibly be covered with a conventional electrolytic deposit, terminated by a layer of gold.
  • the production of the threaded hole 19 and of the screw 12 are therefore very simple compared to the production of the cavities coupled by an iris, which include the conventional filters.
  • the size of the screw 12 is much smaller than the size of a cavity coupled by an iris.
  • Such a filter may include a plurality of identical circulated coaxial lines aligned in a plane of symmetry of the guide, where the electric field is maximum. They are spaced by an odd number of quarters of the wavelength corresponding to the center frequency of the band to be passed.
  • FIG. 5 diagrammatically represents a second embodiment of the filter according to the invention, comprising 5 resonators similar to that described above.
  • Three resonators, comprising screws 21 to 23, are located on a first line and two resonators, comprising two screws 24 and 25, are located on a second line, these two lines being symmetrical with respect to the axis XX 'of symmetry of the waveguide 27.
  • These two lines are located in a plane of symmetry of the waveguide 27, where the electric field vector E is maximum.
  • two successive resonators are spaced by a half wavelength ⁇ 'from the center frequency of a frequency band to be passed.
  • the resonators located on the first line are offset by a quarter of a wavelength relative to the resonators located on the second line.
  • Screw 24 is located midway between screws 21 and 22.
  • Screw 25 is located midway between screws 22 and 23. This arrangement of the resonators provides a transfer function with very low attenuation for the frequencies to be left pass; and an attenuation transfer function proportional to the number of resonators, for the frequencies to be eliminated.
  • the screws 21 to 25 have a diameter of 3 millimeters which is reduced to 0.63 millimeters in the part 17 constituting the inner conductor of the coaxial line.
  • This part 17 has a length of 5.05 millimeters.
  • the coaxial line has a characteristic impedance of 96 ohms.
  • the value of the characteristic impedance of the coaxial line partly determines the value of the coupling between the coaxial line and the waveguide; and determines the overvoltage factor of the resonator, in other words determines the attenuation and the width of the attenuated band.
  • the characteristic impedance of the coaxial line can be between 60 and 100 ⁇
  • FIG. 6 represents the graph G of the attenuation and the graph R of the standing wave rate for the exemplary embodiment represented in FIG. 5, used to eliminate the frequency band BA, from 14 to 14.5 GHz, and to pass the BP frequency band from 10.7 to 12.75 GHz. It appears that the attenuation of the band from 14 to 14.5 GHz is more than 20 dB and that the standing wave rate in the band from 10.7 to 12.75 GHz, expressed in absolute value, is less than 1.15, while the insertion losses are less than 0.2 dB. These figures are to be compared with the performance of a conventional filter made up of five cavities coupled to a waveguide by irises.
  • a conventional filter provides attenuation, of the band to be eliminated, greater than 50 dB, and a standing wave rate, in the passband, of less than 1.05; with insertion losses of less than 0.05 dB.
  • the filter according to the invention therefore has more modest performance, but on the other hand the price of the realization tion is about 3 to 4 times smaller, and the size is much reduced.
  • the invention is not limited to the examples described above. Many variants are within the reach of those skilled in the art, as regards the production of the coaxial line constituting the resonator and as regards its integration into a waveguide of an emission device. microwave reception.
  • FIGs 7 and 8 show a third embodiment of a filter according to the invention.
  • This example comprises a single resonator essentially constituted by a socket 32 screwed into a threaded hole 39 which is drilled in the largest wall of a guide 31 with rectangular section.
  • Figure 8 shows the socket 32 seen in section.
  • the axis of symmetry ZZ 'of the sleeve 32 is located in the plane of symmetry of the guide 31.
  • the outer surface of the sleeve 32 has a thread 35 over its entire length.
  • a slot 34 makes it possible to screw or unscrew the socket 32 in the hole 39.
  • a nut 38 screwed onto the socket 32 makes it possible to immobilize the socket 32 after having adjusted its position to obtain agreement on the central frequency of the frequency band to be eliminated.
  • the socket 32 is hollow. Its interior has a smooth cylindrical surface 36 and it contains a rod 37 having a cylindrical shape whose axis of symmetry of revolution coincides with the axis of symmetry of revolution ZZ 'of the sleeve 32.
  • the diameter of the rod 37 is less than the inside diameter of the socket 32, and its length is equal to an odd number of quarters of the wavelength corresponding to the central frequency of the band to be eliminated. In this example, the length of the rod 37 is equal to a quarter of a wavelength.
  • the length of the rod 37 is greater than the depth of the sleeve 32 so that the rod 37 protrudes at the mouth of the sleeve.
  • the interior of the socket and a free part of the threaded hole 39 constitute the outer conductor of a coaxial line; while the rod 37 constitutes an inner conductor of this line and that the end of the rod 37 constitutes a plunger penetrating into the waveguide 31 to constitute a capacitive susceptance connected to the end of the coaxial line.
  • the bottom 33 of the socket 32 has a flat surface, orthogonal to the axis of symmetry ZZ ', and constitutes a short circuit at the other end of the coaxial line.
  • the length of the socket 32 is less than a quarter of a wavelength so that the socket does not protrude inside the guide 31, and that part of the threaded hole 39 is not occupied by the socket 32 and forms part of the coaxial line.
  • the third embodiment allows the use of a guide section 31 having a wall of thickness less than the length of the coaxial line to be produced, while the first embodiment requires a waveguide having a wall thickness greater than the length of the coaxial line to be produced.
  • FIG. 9 represents a fourth embodiment of a filter according to the invention, comprising a resonator 42 constituted by a socket, analogous to the socket 32 described above described, screwed into a threaded hole 43 which is drilled in the wall of a waveguide 41 with circular section.
  • the conductor 44 of the short-circuited coaxial line has its major axis which passes through the center of the guide and which is parallel to the electric field E of the waves to be eliminated.
  • FIG. 10 represents a fifth embodiment of a filter according to the invention, which is combined with a transition from coaxial cable to waveguide.
  • This transition comprises a waveguide 49, of rectangular section, closed by a metal plate 51; and comprises an antenna 50 immersed in the guide 49.
  • the antenna 50 is connected to the central conductor of a coaxial cable 52 by a coaxial connector 53.
  • the antenna 50 passes through a hole 54 drilled in the wall of the guide 49, on its largest side, and in its plane of symmetry.
  • This transition also constitutes a band eliminator filter thanks to a plurality of resonators constituted by sockets 55 to 57 screwed into threaded holes, 58 to 60. These sockets 55 to 57 are similar to the socket 32 described. previously.
  • the antenna 50 is placed at a distance equal to a quarter of the wavelength ⁇ 'corresponding to the central frequency of the frequency band to be passed, relative to the metal plate 51 closing the waveguide.
  • the nearest resonator, 55 is placed at a distance at least equal to the wavelength ⁇ 'corresponding to the central frequency of the band to be passed, relative to the antenna 50.
  • the other resonators are located at regular intervals, equal to odd multiples of a quarter of the wavelength ⁇ 'corresponding to the center frequency of the band to be passed. For example, the intervals are all equal to a quarter of a wavelength.

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EP90122545A 1989-11-30 1990-11-26 Bandsperrfilter für Mikrowellenhohlleiter Ceased EP0430136A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8915805A FR2655199B1 (fr) 1989-11-30 1989-11-30 Filtre eliminateur de bande pour guide d'ondes hyperfrequences.
FR8915805 1989-11-30

Publications (1)

Publication Number Publication Date
EP0430136A1 true EP0430136A1 (de) 1991-06-05

Family

ID=9387982

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90122545A Ceased EP0430136A1 (de) 1989-11-30 1990-11-26 Bandsperrfilter für Mikrowellenhohlleiter

Country Status (7)

Country Link
US (1) US5105174A (de)
EP (1) EP0430136A1 (de)
JP (1) JPH03195102A (de)
CA (1) CA2031076A1 (de)
FR (1) FR2655199B1 (de)
IL (1) IL96466A (de)
TR (1) TR24998A (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI94299C (fi) * 1993-05-13 1995-08-10 Nokia Telecommunications Oy Koaksiaaliresonaattori
US6118356A (en) * 1998-09-16 2000-09-12 Hughes Electronics Corporation Microwave cavity having a removable end wall
EP2654066B1 (de) * 2012-04-20 2019-10-23 NXP USA, Inc. Mikrowellenadapter und zugehörige Oszillatorensysteme
RU2649089C1 (ru) * 2017-01-19 2018-03-29 Алексей Валентинович Палицин Перестраиваемый полосно-запирающий волноводный фильтр
RU210173U1 (ru) * 2021-11-02 2022-03-30 Акционерное общество "Научно-производственное предприятие "Исток" имени А.И. Шокина" (АО "НПП "Исток" им. Шокина") Коаксиально-волноводный переход

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2645679A (en) * 1947-11-29 1953-07-14 Standard Telephones Cables Ltd Method of controlling susceptance of a post type obstacle
GB843341A (en) * 1956-12-20 1960-08-04 Gen Electric Co Ltd Improvements in or relating to electric filter circuits
US4752753A (en) * 1986-09-04 1988-06-21 Wavecom Coaxial waveguide band reject filter

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3876963A (en) * 1973-12-03 1975-04-08 Gerald Graham Frequency filter apparatus and method
FR2326077A1 (fr) * 1975-09-25 1977-04-22 Cit Alcatel Filtre hyperfrequence stabilise en temperature
US4035749A (en) * 1976-04-06 1977-07-12 Harvard Industries, Inc. Microwave tuning screw assembly having positive shorting
DE2808369A1 (de) * 1978-02-27 1979-09-06 Siemens Ag Mikrowellenfilter mit einem unterhalb seiner h tief 10 -grenzfrequenz betriebenen rechteckhohlleiter
FR2477783A1 (fr) * 1980-03-04 1981-09-11 Thomson Csf Dispositif d'accord a capacite variable et filtre hyperfrequences accordable comportant au moins un tel dispositif
FR2583597A1 (fr) * 1985-06-13 1986-12-19 Alcatel Thomson Faisceaux Filtre passe-bande hyperfrequences en mode evanescent
US4780693A (en) * 1986-11-12 1988-10-25 Hughes Aircraft Company Probe coupled waveguide multiplexer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2645679A (en) * 1947-11-29 1953-07-14 Standard Telephones Cables Ltd Method of controlling susceptance of a post type obstacle
GB843341A (en) * 1956-12-20 1960-08-04 Gen Electric Co Ltd Improvements in or relating to electric filter circuits
US4752753A (en) * 1986-09-04 1988-06-21 Wavecom Coaxial waveguide band reject filter

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
REVIEW OF THE ELECTRICAL COMMUNICATION LABORATORIES. vol. 18, no. 7/8, juillet 1970, TOKYO JP pages 493 - 511; H.SUGAHARA ET AL.: "Small-sized channel branching filter for microwave" *

Also Published As

Publication number Publication date
JPH03195102A (ja) 1991-08-26
US5105174A (en) 1992-04-14
TR24998A (tr) 1992-09-01
FR2655199A1 (fr) 1991-05-31
IL96466A (en) 1994-01-25
CA2031076A1 (fr) 1991-05-31
FR2655199B1 (fr) 1992-10-02

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