WO2009095446A1 - Ensemble condensateur à capacité variable, procédé de fabrication et utilisation - Google Patents

Ensemble condensateur à capacité variable, procédé de fabrication et utilisation Download PDF

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Publication number
WO2009095446A1
WO2009095446A1 PCT/EP2009/051019 EP2009051019W WO2009095446A1 WO 2009095446 A1 WO2009095446 A1 WO 2009095446A1 EP 2009051019 W EP2009051019 W EP 2009051019W WO 2009095446 A1 WO2009095446 A1 WO 2009095446A1
Authority
WO
WIPO (PCT)
Prior art keywords
capacitor
actuator
electrode
capacitor arrangement
arrangement according
Prior art date
Application number
PCT/EP2009/051019
Other languages
German (de)
English (en)
Inventor
Richard Matz
Carsten Giebeler
Jörg ZAPF
Original Assignee
Siemens Aktiengesellschaft
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 Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO2009095446A1 publication Critical patent/WO2009095446A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G5/00—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture
    • H01G5/16—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture using variation of distance between electrodes

Definitions

  • Capacitor capacitance capacitor assembly Method of fabricating the capacitor assembly, and use of the capacitor assembly
  • the invention relates to a capacitor arrangement with at least one variable-capacitance capacitor (varactor), comprising at least one capacitor electrode, which is arranged on a capacitor carrier, and at least one capacitor counter-electrode, which is opposite to the capacitor electrode on an actuator is arranged in a changeable by means of the actuator capacitor-electrode spacing for adjusting the capacitance.
  • a method for producing and using the capacitor arrangement are specified.
  • a capacitor arrangement with a capacitor whose capacitance can be changed with high quality is required, for example, for a voltage-controlled oscillator circuit (voltage controlled oscillator, VCO).
  • VCO voltage controlled oscillator
  • Such a circuit is used as a generator of reference frequencies and for mixing channel frequencies and carrier frequencies in communications engineering.
  • tunable capacitances are also used for tunable filters in high-frequency and microwave technology.
  • a frequency filter is for example a bandpass filter.
  • the bandpass filter is transmissive to a high frequency signal (passband) within a certain frequency band. This means that an attenuation amount for a high frequency signal within this frequency band is low.
  • the capacitor carrier is for example a LTCC (Low Temperature Cofired Ceramics), Substrate. On the capacitor carrier, the capacitor electrode is applied.
  • LTCC Low Temperature Cofired Ceramics
  • the actuator of the capacitor assembly is a bending element in the form of a piezoceramic bending transducer, which on the
  • Capacitor carrier is electrically soldered or glued.
  • the bending transducer can be configured as a so-called bimorph.
  • a piezoelectric element consisting of a piezoelectrically active ceramic layer and electrode layers mounted on both sides is firmly connected to a piezoelectrically inactive layer.
  • the piezoelectrically active ceramic layer is deflected.
  • the piezoelectrically inactive layer is not deflected by the activation of the electrode layers of the piezoelectric element. Due to the firm connection between the layers, there is a bending of the bending transducer.
  • the bending transducer is designed and mounted on the capacitor carrier with the aid of solder or adhesive such that one of its electrode layers acts as a capacitor counter electrode. Due to the bending of the bending transducer, the capacitor-electrode distance between see see the capacitor electrode and the capacitor counter electrode. The capacitance of the capacitor changes.
  • the object of the present invention is to provide a variable capacitance capacitor arrangement which is more reliable in comparison with the prior art.
  • a capacitor arrangement is provided with at least one capacitor with variable capacitance, comprising at least one capacitor electrode, which is arranged on a capacitor carrier, and at least one capacitor counter-electrode, which is opposite to the capacitor electrode on an actuator is arranged in a changeable by means of the actuator capacitor-electrode spacing for adjusting the capacitance.
  • the capacitor arrangement is characterized in that at least one connecting means for generating a pressure contact between the capacitor carrier and the actuator is present. The actuator adjusts the capacitor electrode distance. Due to the pressure contact, the actuator is only fixed on the capacitor carrier.
  • a method for producing the capacitor arrangement is also specified with the following method steps: a) providing the capacitor carrier with the capacitor electrode and providing the actuator with the capacitor counterelectrode, b) bringing the capacitor carrier and the actuator together in such a way in that the capacitor electrode and the capacitor counterelectrode are arranged opposite one another, and c) attaching the connection means such that the capacitor carrier and the actuator are connected to one another by means of pressure contact.
  • the actuator for example, a strip-shaped bending transducer is placed on the capacitor carrier and fixed with the connecting means. Electric control of the bending transducer leads to a convex bending. The distance between the capacitor electrode and the capacitor counter electrode changes.
  • the film is laminated. It is also conceivable that the film is glued. The film can be applied completely via the actuator and the capacitor carrier. It is also conceivable that the film only partially covers the actuator and the capacitor carrier.
  • the potting compound can be applied in a structured or unstructured manner.
  • the actuator is an electrically controllable actuator.
  • the capacitor-electrode distance can be adjusted.
  • the electrically controllable actuator for electrical control by means of the connecting means is electrically contacted.
  • the actuator is a bimetal (bimetallic) - actuator.
  • Such an actuator consists for example of two firmly interconnected metal strips of metals with different thermal expansion coefficients.
  • the electrical activation of an actuator electrode causes the heating of an adjacent actuator functional layer that may be electrically isolated from the actuator electrode and, as a result of the heating, causes the actuator to bend.
  • the actuator is a magnetostrictive actuator.
  • By controlling the actuator electrode is in an actuator functional layer of the magnetostrictive actuator magnetic field coupled.
  • the Weiss domains of the magnetostrictive material align themselves.
  • this actuator-functional layer is firmly connected to an actuator functional layer of a non-magnetic material, there is a bending of the actuator.
  • the actuator can operate thermally or magnetostrictively.
  • the actuator is a piezoelectric actuator.
  • the piezoelectric actuator has at least one piezoelectric element.
  • the piezoelectric element has a piezoelectric layer and electrode layers arranged on both sides (actuator electrodes). By electrical actuation of the actuator electrodes, an electric field is coupled into the piezoelectric layer. It comes to the expansion change in the piezoelectric layer and due to the expansion change to the actuating action of the actuator.
  • the actuator is a piezoelectric bending element (piezoelectric actuator).
  • piezoelectric actuator The configuration of the piezoelectric actuator is arbitrary. It is crucial that the piezoelectrically induced deflection of the actuator is large enough so that a desired change in the distance between the capacitor electrodes can be achieved.
  • a piezoelectric actuator can be used which has a plurality of piezo elements stacked one above the other to form an actuator body. The piezoelectric elements can be glued together. This is suitable, for example, for piezo elements with piezoelectric layers of a piezoelectric polymer such as polyvinylidene difluoride (PVDF).
  • PVDF polyvinylidene difluoride
  • piezoelectric layers made of a piezoceramic material are conceivable.
  • the piezoceramic material is, for example, a lead zirconate titanate (PZT) or a zinc oxide (ZnO).
  • PZT lead zirconate titanate
  • ZnO zinc oxide
  • the piezoelectric elements with piezoelectric layers of piezoceramic material for example, not glued together, but connected in a common sintering process to a Aktorkorper in monolithic multilayer construction.
  • the piezoelectric actuator is a piezoelectric bending transducer. By a relatively low drive voltage, a relatively large deflection can be achieved in the bending transducer.
  • a drive voltage of less than 10 V is sufficient to cause a deflection of the bending transducer of more than 10 ⁇ m. Due to the large achievable deflection, the distance between the capacitor electrode and capacitor counter electrode can be varied within a wide range. This makes it possible to vary the capacitance of the capacitor in a wide range.
  • the bending transducer can, as described above, be designed as a bimorph.
  • a bending transducer in the form of a multimorph which has a plurality of piezoelectrically active layers which are firmly connected to one another.
  • the piezoelectrically active layers can be combined to form a single piezoelement.
  • the piezoelectrically active layers together form the piezoelectric overall layer of the piezoelectric element as stacked partial layers. It is also conceivable that a plurality of piezoelectric elements, each having a piezoelectrically active layer, are arranged to form a multilayer composite.
  • a shape of the bending transducer can also be arbitrary.
  • the bending transducer can be strip-shaped.
  • the bending element has a round base.
  • Such a bending element may be referred to as a circular disk bender.
  • the bending element is self-supporting. It does not have to be specially clamped or held.
  • the electrical actuation of the circular disc bender results in a peripheral peripheral bearing surface. che.
  • Typical dimensions of a circular bending transducer are a few 100 microns as the thickness of the layers and 10 to 20 mm in diameter, whereby a stroke of a few lO ⁇ m is achieved in the center of the bending transducer.
  • the layers of the circular disc bender may be dimensioned thinner in the middle than at the edge.
  • Capacitor can be varied within a wide range.
  • a dielectric with a relative dielectric constant of more than 10 can be arranged within the distance between the capacitor electrode and the capacitor counterelectrode.
  • a dielectric having a dielectric constant greater than 50 is used. This dielectric is referred to as a high dielectric material.
  • the dielectric is arranged in such a way that the electric field which is generated by the driving of the capacitor electrode and the capacitor counterelectrode builds up in the dielectric.
  • the dielectric layer is applied directly and directly to the capacitor electrode or the capacitor counterelectrode. It is also conceivable that in each case a dielectric layer is applied to both capacitor electrodes.
  • the actuator can simply be placed on a surface of the capacitor carrier.
  • the actuator is arranged in a recess (Kavitat) of the capacitor carrier.
  • the bearing surfaces of the Actuator on the capacitor carrier be coated friction, for example, with Teflon or hard nitrides.
  • the described capacitor arrangement with the variable capacitance is used in particular in tunable oscillators.
  • the capacitor arrangement is used to set a voltage-controlled oscillator circuit.
  • the tunable oscillators are used in radio frequency and microwave technology, among others.
  • the capacitor arrangement is also used for setting a frequency band of a frequency filter. Due to the possibility of being able to change a frequency band of a frequency filter by electrical activation of the capacitor arrangement in a wide range, the invention makes it possible to realize a concept of message or mobile radio technology, which is referred to as "software defined radio" (SDR) ,
  • SDR software defined radio
  • the aim of the SDR is to realize non-discrete frequency bands, but arbitrarily (continuously) changeable frequency bands for the message or mobile radio technology.
  • a basic building block for implementing the SDR is provided.
  • the capacitor arrangement is also used for adjusting the impedance of a matching circuit.
  • Impedance matching is required to avoid signal reflections between circuit elements, for example at the input and output of a power amplifier. It is usually realized by suitably combined passive components, in particular coils and capacitors. The function is thus limited to a finite frequency interval. When shifting the operating frequency of a circuit, such as by changing a filter setting, therefore, the impedance adjustments to the new frequency band are tuned.
  • self-modulation of an adjacent signal spectrum by the electrostatic forces acting across the air gap is avoided, and the generation of sub and harmonic waves is suppressed.
  • the capacitor arrangement is particularly suitable for applications with high linearity requirements (for example, base stations of a mobile radio network).
  • the capacitor counterelectrode of the signal circuit can be galvanically isolated from the control circuit.
  • the signal circuit can therefore be designed without functional losses for a high current carrying capacity.
  • a peripheral support of the actuator, especially the disc bender, ensures a stable and symmetrical movement.
  • FIGS. 1 to 7 each show an exemplary embodiment of a capacitor arrangement with capacitors having tunable capacitances, each in a lateral cross section.
  • the exemplary embodiments relate in each case to a capacitor arrangement 100 with variable capacitances, comprising two series-connected capacitors 101 and 102 each having a capacitor electrode 3a and 4a and a capacitor counter electrode 8 arranged opposite the capacitor electrodes in a variable capacitor electrode distance 15 to the capacitor electrodes.
  • the capacitor counter electrode projects beyond the capacitor electrodes.
  • the capacitor electrodes are applied to a capacitor carrier 1, which is preferably made of a dimensionally stable ceramic in solid material or multilayer structure (LTCC, HTCC (High Tempe- Cofired Ceramics).
  • the capacitor electrodes are electrically contacted via the through-contacts (vias) 3 and 4 integrated in the capacitor carrier.
  • a layer 100 of a thickness of a few 100 nm to a few ⁇ m of high-dielectric ceramic in thick-film or thin-film technology is applied.
  • the capacitor counter-electrode is applied to an actuator 103.
  • the actuator is a piezoceramic bending transducer with a circular base (disc bender).
  • the piezoceramic bending transducer is designed as a multimorph and consists of two piezoceramic layers 6 and 7, which are provided for coupling electric fields with electrode layers 9 and 10.
  • the layers are a few 100 ⁇ m thick.
  • the diameter of the bending transducer is 10 mm to 20 mm.
  • Both the capacitor electrodes and the circular disk bender are arranged in a recess (depression) 2 of the capacitor carrier.
  • the circular disc bender lies in the recess on a peripheral support 16 made of Teflon.
  • the pad is made of a hard nitride.
  • the bending transducer is pressed by two spring elements 11 and 12 against the capacitor carrier ( Figure 1).
  • the spring elements act as connection means for generating a pressure contact between the capacitor carrier and the actuator.
  • the spring elements are firmly connected to the capacitor carrier.
  • the spring elements serve for electrical contacting of the electrode layers of the bending transducer.
  • the spring elements are soldered to electrical through contacts 13 and 14 on the capacitor carrier.
  • a force-free bonding contact 17 is sufficient instead of the spring elements 11 and 12 (see Example 1).
  • the bending transducer is fixed to the spring element 18 via the metallic housing cover 19, which is connected to the Uber Dahlring 20 with the substrate screw in.
  • Spring element 18, housing cover 19 and Uber Dahlring 20 together form the connecting means for generating the pressure contact.
  • the electrode layer 10 of the bending transducer is electrically contacted, for example, set to ground potential. The electrical control of the bending transducer then takes place via the voltage applied to the feedthrough 13 electrical voltage.
  • the bending transducer is fixed laterally in the housing cover 19 by means of suitable recesses.
  • the housing cover here consists of a multi-layer board, for example of the usual material FR4 or FR5, with embedded metal surfaces 22 and 23.
  • the spring rings 24, 25 and 26 serve the vertical fixation of the bending element and the capacitor carrier. Housing cover and spring rings act as connecting means for generating the pressure contact.
  • the electrodes 9 and 10 are electrically contacted to supply the control voltage via the spring rings 24 and 25. 4:
  • the connecting means for generating the pressure contact between see the capacitor carrier and the actuator is an elastic film 18 made of silicone.
  • the contacting of the electrode layers of the bending transducer takes place subsequently through the laminated film.
  • contact windows 11 will be opened by laser ablation.
  • the electrical connection of the bending transducer is then achieved by a conductor plane 12 applied to the film.
  • the conductor plane 12 is realized by a metallic structure, which is applied by screen printing of a conductor paste or a conductive adhesive.
  • a less elastic film 18 is used, which is open to reduce the contact pressure over the bending transducer (Figure 6). This can be done, for example, by a stamping process before lamination or by laser ablation after lamination. 7:
  • an elastic potting compound 27 is applied, for example, by a screen-printing process, the depression 2 also being partially filled depending on the viscosity.
  • the structuring can already be achieved by the printing process or subtractive by photolithography or laser ablation.
  • contact windows 19 can also be introduced here, so that the potting compound also acts as a carrier of another conductor plane 12.
  • the conductor level can also be realized by means of an elastic conductive adhesive applied by means of screen printing.
  • control voltages for the bending transducer can be supplied via the plated-through holes 13 and 14.
  • the contacting of the electrode layers of the bending transducer takes place subsequently through the laminated film.
  • contact windows 11 will be opened by laser ablation.
  • the electrical connection of the bending transducer is then achieved by a conductor plane 12 applied to the film.
  • the conductor plane 12 is realized by a metallic structure, which is applied by screen printing.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Micromachines (AREA)

Abstract

L'invention concerne un ensemble condensateur doté d'au moins un condensateur à capacité variable (varacteur), présentant au moins une électrode de condensateur, qui est disposée sur un support de condensateur; et au moins une contre-électrode de condensateur, qui est disposée en vis-à-vis de l'électrode de condensateur sur un organe de réglage, la distance entre les électrodes de condensateur pouvant être modifée par l'organe de réglage pour régler la capacité. Le procédé de fabrication de l’ensemble condensateur comprend les étapes suivantes : a) utilisation du support de condensateur muni de l'électrode de condensateur, et utilisation de l'organe de réglage muni de la contre-électrode de condensateur; b) réunion du support de condensateur et de l'organe de réglage de manière à disposer l'électrode de condensateur en regard de la contre-électrode de condensateur; et c) mise en place du moyen de liaison de telle sorte que le support de condensateur et l'organe de réglage soient mutuellement reliés par contact à pression directe. L'organe de réglage est notamment un transducteur de flexion piézoélectrique sous la forme d'un élément de flexion en forme de disque. Le transducteur de flexion est posé sur le support de condensateur et simplement fixé en position par le moyen de liaison. La commande électrique du transducteur de flexion entraîne une déformation convexe. La distance entre l'électrode de condensateur et la contre-électrode de condensateur se modifie. L'ensemble condensateur est par exemple utilisé dans un oscillateur commandé en tension (VCO). L'ensemble condensateur est notamment utilisé dans le domaine des télécommunications et de la téléphonie mobile. Avec cet ensemble condensateur, on fournit un élément de base du système de radio logicielle (SDR).
PCT/EP2009/051019 2008-01-31 2009-01-29 Ensemble condensateur à capacité variable, procédé de fabrication et utilisation WO2009095446A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008007034.3 2008-01-31
DE200810007034 DE102008007034A1 (de) 2008-01-31 2008-01-31 Kondensatoranordnung mit veränderbarer Kapazität, Verfahren zum Herstellen der Kondensatoranordnung und Verwendung der Kondensatoranordnung

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WO2009095446A1 true WO2009095446A1 (fr) 2009-08-06

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Publication number Priority date Publication date Assignee Title
US10241223B2 (en) 2015-11-19 2019-03-26 Halliburton Energy Services, Inc. Downhole piezoelectric acoustic transducer

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Publication number Priority date Publication date Assignee Title
US10241500B2 (en) 2015-08-10 2019-03-26 Buerkert Werke Gmbh Film transducer and actuator strip for a film transducer

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WO2005059932A1 (fr) * 2003-12-18 2005-06-30 Siemens Aktiengesellschaft Condensateur a capacite modulable, procede de production dudit condensateur et utilisation dudit condensateur
EP1562207A1 (fr) * 2004-02-04 2005-08-10 Stmicroelectronics SA Microsystème électromécanique pouvant basculer entre deux positions stables

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WO2005059932A1 (fr) * 2003-12-18 2005-06-30 Siemens Aktiengesellschaft Condensateur a capacite modulable, procede de production dudit condensateur et utilisation dudit condensateur
EP1562207A1 (fr) * 2004-02-04 2005-08-10 Stmicroelectronics SA Microsystème électromécanique pouvant basculer entre deux positions stables

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Publication number Priority date Publication date Assignee Title
US10241223B2 (en) 2015-11-19 2019-03-26 Halliburton Energy Services, Inc. Downhole piezoelectric acoustic transducer

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