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EP0165158A1 - Dielektrischer Filter mit veränderbarer Mittenfrequenz - Google Patents

Dielektrischer Filter mit veränderbarer Mittenfrequenz Download PDF

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Publication number
EP0165158A1
EP0165158A1 EP85401036A EP85401036A EP0165158A1 EP 0165158 A1 EP0165158 A1 EP 0165158A1 EP 85401036 A EP85401036 A EP 85401036A EP 85401036 A EP85401036 A EP 85401036A EP 0165158 A1 EP0165158 A1 EP 0165158A1
Authority
EP
European Patent Office
Prior art keywords
filter
faces
resonator
dielectric
small
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.)
Withdrawn
Application number
EP85401036A
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English (en)
French (fr)
Inventor
Bertrand D'albaret
Antoine Colombani
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.)
Compagnie Electronique et de Piezoelectricite CEPE
Original Assignee
Compagnie Electronique et de Piezoelectricite CEPE
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 Compagnie Electronique et de Piezoelectricite CEPE filed Critical Compagnie Electronique et de Piezoelectricite CEPE
Publication of EP0165158A1 publication Critical patent/EP0165158A1/de
Withdrawn legal-status Critical Current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
    • H01P7/00—Resonators of the waveguide type
    • H01P7/08—Strip line resonators

Definitions

  • the present invention relates to a dielectric filter with variable central frequency comprising at least one dielectric resonator constituted by a dielectric ceramic body coated with electrodes as well as means for electromagnetic coupling of signal input and output on the filter.
  • Ultra-high frequency (UHF) filters are widely used in the art, for example, in telecommunications to choose a specific frequency band. In frequencies up to about 700 MHz, filters with piezoelectric resonators can be used. However, for the entire UHF band, extending up to 3 GHz, these are no longer suitable and use is made of dielectric filters which have performances similar to cavity filters but which are much less expensive and bulky. In addition, in certain applications, the bandwidth of the piezoelectric filters proves to be too narrow.
  • Dielectric filters of this type have been described in French application 82.18236 filed on October 23, 1982 in the name of THOMSON-CSF.
  • Such filters of the parallelepiped type use compositions of the (Zr, Sn) TI0 4 type .
  • bandpass filters can be produced by placing a plurality of resonators next to each other. Generally, it is preferred to use quarter-wave type resonators because of their shorter length.
  • the electrode metallizations of these resonators are respectively mutually parallel and perpendicular to the insulating substrate on which said substrates are fixed.
  • the coupling between these resonators is made by mutual inductance.
  • the connection to the input and the output of the filter can be done either by welding directly on the electrode of the first and last resonator respectively, or by means of a loop placed above the first and last resonator as an exciter and collector.
  • resonators having a specific and determined frequency are used and by coupling said resonators according to the coupling coefficients required by the calculation of the filter, and this by carefully adjusting the distance between the resonators.
  • a plurality of resonators generally placed close to each other is used.
  • the natural frequency of each resonator is then tuned to the different frequencies of the channels and it is sufficient to switch the input and the output of the filter to the desired resonator to select the corresponding channel.
  • such a solution requires the use of as many resonators as channels, and per filter pole. This results in a significant bulk of the filter, which becomes prohibitive when the number of channels desired is greater than two.
  • the invention makes it possible to solve the problem posed and to use only a single resonator, or a single set of resonators coupled together according to the quality of the desired filter, while allowing the selection of a large number of channels.
  • the dielectric filter with variable central frequency is characterized in that it comprises a variable capacitance connected between the electrodes of the dielectric resonator, in a capacitive zone of said resonator, making it possible to continuously vary the central frequency of said filter. It is noted that such filters allow a displacement of the central frequency, with a substantially constant passband, of several times the value of this passband, with a very low level loss.
  • the filter according to the invention is characterized in that it comprises a plurality of dielectric resonators arranged close to one another and cut off from each other electromagnetically by air.
  • each resonator is of the quarter-wave type, and consists of a parallelepiped bar having four large faces and two small faces metallized on its large opposite faces. one from the other and on a small face located in the extension of said large faces.
  • the resonators are preferably secured to a support having a low loss factor, by one of their large non-metallized faces.
  • the small metallized faces will preferably be located on the same side of the large faces.
  • variable capacity will be a diode with variable capacity, controlled by a DC voltage generally disposed outside the filter.
  • a ceramic resonator is shown parallelepiped dielectric as mentioned above and described in the French patent application cited above. It comprises a parallelepipedic body 4 of dielectric ceramic coated on two of its large opposite faces with a metal layer 1 and 2 having an electrode function, and on one of its small faces, and in the extension of the electrodes of the large faces 1 and 2 opposite each other, an electrode metallization 3 ensuring operation in a quarter-wave circuit.
  • Figure 2 shows the arrangement of two resonators as described in Figure 1 to achieve a bandpass filter with two poles. It comprises a parallelepipedic housing 15 comprising a rectangular central cavity 16 made of a material having little electromagnetic loss.
  • Two resonators 17 and 18 are made integral with the bottom of the housing 15 in the manner illustrated in this FIG. 2: the electrodes of the large faces respectively 1 and 2, 11 and 12 are arranged parallel to each other, 2 and 11 being distant from a distance d, while the electrodes of the small faces 3 and 13 are placed in the extension of one another. All these electrodes are located in the planes perpendicular to the plane of the cavity 16.
  • the distance d between the resonators 17 and 18 determines the coupling coefficient between these two resonators, this in a manner known per se.
  • the signal is input by Il substantially at the intersection of electrodes 1 and 3, while the signal output is by SI substantially at the intersection of electrodes 12 and 13.
  • FIG. 3 represents an embodiment diagram of a dielectric filter with variable central frequency, with two poles. It consists of two resonators RESI and RES2 arranged as shown in Figure 2. The input of the signal on the filter is done in 1 with an electromagnetic connection or coupling in It arranged as explained in Figure 2. The output of the filter is carried out in S with a connection or a coupling SI carried out at the place indicated in figure 2.
  • Electrodes 1 and 2 on the side of the small non-metallized parallelepiped face 4, are connected, to the electrode 1, the first end of a capacitor C1, the other end of which is connected on the one hand to a resistor RI and on the other hand, to the cathode of a varicap diode Dl whose anode is connected to the end of electrode 2, on the side of the small non-metallized face.
  • the second end of the resistor R1 is connected to a variable DC voltage source V.
  • the electrode 12 of the resonator RES2 is connected to a first end of the capacitor C2, the second end of which is connected on the one hand to the cathode of the varicap diode, the other end of which is connected to the electrode 11 near its end on the side of the small non-metallized face of the resonator, and on the other hand to the resistor R2, the other end of which is also connected to the variable DC voltage source V.
  • a shock inductor L1 In parallel between the input I and the ground C is placed a shock inductor L1, while at the output is also placed a shock inductor L2.
  • these chokes can have variable values depending on the application envisaged and are not properly part of the filter according to the invention. They make it possible to guarantee the polarization of the diode with variable capacity, by their resistance having an adapted value.
  • FIG. 4 shows the passbands of the filter as a function of the voltage V applied to the varicap diodes for a filter having the parameters mentioned in the example below.
  • the OdB level corresponds to the level of the input signal.
  • the bandwidths of the - 3dB filter are mentioned numerically in the figure, making it possible to note the excellent results obtained using the filter according to the invention.
  • each resonator is placed at a distance d from the neighboring resonator (see FIG. 2) according to the desired coupling coefficient in a manner well known to those skilled in the art.
  • Each circuit, such as CI, Dl and RI of each resonator such as RESI is connected in the same way to said resonator, the end of each resistor, such as RI, being connected directly to the voltage source V.
  • the connections Il and SI are respectively made on the first filter of the plurality and on the last filter of the latter. In all cases, it will however be necessary to provide polarization means suitable for each diode with variable capacitance.
  • the electrode metallizations are made of silver, have a thickness of approximately 50 ⁇ , and are deposited using a lacquer by screen printing.
  • the entire resonator is placed in an aluminum housing, the distance between the faces of the resonators and the upper and lower walls of the housing being of the order of 3 mm.
  • electrode has been used to define the conductive walls of the resonant cavity.

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  • Control Of Motors That Do Not Use Commutators (AREA)
EP85401036A 1984-05-30 1985-05-28 Dielektrischer Filter mit veränderbarer Mittenfrequenz Withdrawn EP0165158A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8408498 1984-05-30
FR8408498A FR2565438B1 (fr) 1984-05-30 1984-05-30 Filtre dielectrique a frequence centrale variable.

Publications (1)

Publication Number Publication Date
EP0165158A1 true EP0165158A1 (de) 1985-12-18

Family

ID=9304549

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85401036A Withdrawn EP0165158A1 (de) 1984-05-30 1985-05-28 Dielektrischer Filter mit veränderbarer Mittenfrequenz

Country Status (3)

Country Link
US (1) US4714906A (de)
EP (1) EP0165158A1 (de)
FR (1) FR2565438B1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0406962A3 (en) * 1989-07-07 1991-04-17 N.V. Philips' Gloeilampenfabrieken A filter

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2616594B1 (fr) * 1987-06-09 1989-07-07 Thomson Csf Dispositif filtrant hyperfrequence accordable a resonateur dielectrique, et applications
US4835499A (en) * 1988-03-09 1989-05-30 Motorola, Inc. Voltage tunable bandpass filter
AU638461B2 (en) * 1989-07-07 1993-07-01 Philips Electronics Australia Limited A filter
GB2247125B (en) * 1990-08-16 1995-01-11 Technophone Ltd Tunable bandpass filter
US5065120A (en) * 1990-09-21 1991-11-12 Motorola, Inc. Frequency agile, dielectrically loaded resonator filter
FI94298C (fi) * 1993-03-03 1995-08-10 Lk Products Oy Menetelmä ja kytkentä suodatintyypin vaihtamiseksi
FI95851C (fi) * 1993-09-10 1996-03-25 Lk Products Oy Siirtojohtoresonaattorin sähköinen taajuudensäätökytkentä sekä säädettävä suodatin
FI110148B (fi) * 1993-09-10 2002-11-29 Filtronic Lk Oy Useita resonaattoreita käsittävä radiotaajuussuodatin
US6453157B1 (en) 1998-03-23 2002-09-17 Ericsson Inc. Radio frequency tracking filter
EP1312132A1 (de) 2000-08-22 2003-05-21 Paratek Microwave, Inc. Kammfilter mit abstimmbaren dielektrischen kondensatoren
WO2007000578A2 (en) 2005-06-25 2007-01-04 Omni-Id Limited Electromagnetic radiation decoupler
GB0611983D0 (en) 2006-06-16 2006-07-26 Qinetiq Ltd Electromagnetic radiation decoupler
GB0624915D0 (en) * 2006-12-14 2007-01-24 Qinetiq Ltd Switchable radiation decoupling
GB0625342D0 (en) * 2006-12-20 2007-01-24 Qinetiq Ltd Radiation decoupling
US8794533B2 (en) 2008-08-20 2014-08-05 Omni-Id Cayman Limited One and two-part printable EM tags
US8385867B2 (en) * 2009-06-29 2013-02-26 Silicon Laboratories Inc. Tracking filter for a television tuner
US8230564B1 (en) 2010-01-29 2012-07-31 The United States Of America As Represented By The Secretary Of The Air Force Method of making a millimeter wave transmission line filter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3766494A (en) * 1970-05-21 1973-10-16 Matsushita Electric Industrial Co Ltd Resonance-frequency variable resonator
US4121182A (en) * 1976-02-26 1978-10-17 Matsushita Electric Industrial Co., Limited Electrical tuning circuit
GB2017440A (en) * 1978-02-28 1979-10-03 Matsushita Electric Industrial Co Ltd Tuning device
EP0071508A1 (de) * 1981-07-24 1983-02-09 Thomson-Csf Kleindimensionierter Mikrowellenfilter mit linearen Resonatoren
EP0108003A1 (de) * 1982-10-29 1984-05-09 Thomson-Csf Doppelstreifen-Resonator und nach dieser Art gestaltetes Filter

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3747032A (en) * 1971-10-29 1973-07-17 Gen Electric Arrangement for providing improved linearization of the voltage-frequency characteristic of a resonant circuit having a voltage-variable capacity diode
FR2230121B1 (de) * 1973-05-18 1978-02-10 Materiel Telephonique
US4179673A (en) * 1977-02-14 1979-12-18 Murata Manufacturing Co., Ltd. Interdigital filter
JPS57124902A (en) * 1981-01-26 1982-08-04 Toyo Commun Equip Co Ltd Filter for semicoaxial cavity resonator
US4568895A (en) * 1983-02-17 1986-02-04 International Telephone And Telegraph Corporation Capacitor arrangements, especially for an electronically tunable band pass filter
GB2141880B (en) * 1983-06-18 1986-08-20 Marconi Electronic Devices Electrical resonators

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3766494A (en) * 1970-05-21 1973-10-16 Matsushita Electric Industrial Co Ltd Resonance-frequency variable resonator
US4121182A (en) * 1976-02-26 1978-10-17 Matsushita Electric Industrial Co., Limited Electrical tuning circuit
GB2017440A (en) * 1978-02-28 1979-10-03 Matsushita Electric Industrial Co Ltd Tuning device
EP0071508A1 (de) * 1981-07-24 1983-02-09 Thomson-Csf Kleindimensionierter Mikrowellenfilter mit linearen Resonatoren
EP0108003A1 (de) * 1982-10-29 1984-05-09 Thomson-Csf Doppelstreifen-Resonator und nach dieser Art gestaltetes Filter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0406962A3 (en) * 1989-07-07 1991-04-17 N.V. Philips' Gloeilampenfabrieken A filter

Also Published As

Publication number Publication date
FR2565438A1 (fr) 1985-12-06
FR2565438B1 (fr) 1989-09-22
US4714906A (en) 1987-12-22

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19881021

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Inventor name: COLOMBANI ANTOINE

Inventor name: D'ALBARET, BERTRAND