WO2011158619A1 - Variable capacitance device - Google Patents

Variable capacitance device Download PDF

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Publication number
WO2011158619A1
WO2011158619A1 PCT/JP2011/061924 JP2011061924W WO2011158619A1 WO 2011158619 A1 WO2011158619 A1 WO 2011158619A1 JP 2011061924 W JP2011061924 W JP 2011061924W WO 2011158619 A1 WO2011158619 A1 WO 2011158619A1
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Prior art keywords
movable beam
dielectric film
capacitance
drive
capacitor
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PCT/JP2011/061924
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French (fr)
Japanese (ja)
Inventor
梅田圭一
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株式会社村田製作所
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Publication of WO2011158619A1 publication Critical patent/WO2011158619A1/en

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    • 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
    • H01G5/18—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 due to change in inclination, e.g. by flexing, by spiral wrapping
    • 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
    • H01G5/01—Details

Definitions

  • the present invention relates to a variable capacity device capable of changing an RF (Radio Frequency) capacity using a MEMS driven by an electrostatic force.
  • RF Radio Frequency
  • FIG. 1 is a diagram illustrating a configuration example of a conventional variable capacitance device.
  • the variable capacity device 101 includes movable plates 102 and 103.
  • the movable plates 102 and 103 each have a doubly supported beam structure and are made of a conductive material.
  • the movable plate 102 and the movable plate 103 are spaced apart from each other.
  • the movable plate 103 has a convex surface facing the movable plate 102 and includes a dielectric layer 104 on the surface.
  • the distance between the movable plates 102 and 103 is narrowed by the driving capacity generated by applying the driving DC voltage between the movable plates 102 and 103, and the dielectric layer 104 is passed from the convex tip region of the movable plate 103 to the movable plate 102.
  • the RF capacity of the variable capacitance device 101 changes according to the contact area.
  • variable capacitance device since the driving DC voltage and the RF signal are applied to the common electrode, a resistor and a capacitor for separating the direct current component and the alternating current component are required for the driving circuit. Since insertion of a resistor or a capacitor causes a complicated circuit configuration and an increase in insertion loss, the applicant of the present application has developed a variable capacitance device that does not require such a resistor or capacitor.
  • 2A is a plan view showing a configuration example of the variable capacitance device 201
  • FIG. 2B is a side sectional view thereof.
  • the variable capacity device 201 includes a support plate 202 and a movable beam 203.
  • the movable beam 203 has a cantilever structure that is supported in parallel to the support plate 202.
  • the support plate 202 is provided with two linear line-shaped electrodes 204 in parallel along the main axis direction of the movable beam 203, and the U-shaped line-shaped electrodes 205 are disposed between both ends of the support plate 202.
  • dielectric films 208A and 208B are provided so as to cover the electrodes 204 and 205, respectively.
  • the movable beam 203 includes one rectangular electrode 206 (shown in FIG. 2B) facing the two electrodes 204 and a U-shaped electrode 207 facing the electrode 205 (see FIG. 2B). 2 (B).).
  • the electrode 204 and the electrode 206 are opposed to each other via the dielectric film 208A and function as an RF capacitor portion, and the electrode 205 and the electrode 207 are opposed to each other via the dielectric film 208B and function as a drive capacitor portion.
  • the drive capacity unit deforms the movable beam 203 by electrostatic attraction by a drive capacity generated by applying a drive DC voltage.
  • the RF capacitor unit is used as an RF capacitor whose capacitance can be changed by connecting the electrode 204 to a high frequency circuit.
  • the variable capacitance device 201 has a structure in which the electrodes 205 and 207 to which the driving DC voltage is applied and the electrodes 204 and 206 to which the RF signal is applied are structurally separated.
  • FIG. 2C is a diagram showing a typical example of driving DC voltage-RF capacitance characteristics in the variable capacitance device having the above-described configuration.
  • the driving DC voltage is in the range from zero to V O
  • the movable beam is in a state of being separated from the dielectric film, and the RF capacitance hardly changes even if the driving DC voltage changes.
  • the driving DC voltage V O ready to tip of the movable beam is brought into line contact with the dielectric film, RF capacity is C O.
  • the tilt angle of the movable beam with respect to the support plate changes while the tip is in line contact with the dielectric film. Almost no change.
  • the driving DC voltage is V MIN
  • the tip of the movable beam is in surface contact with the dielectric film
  • the RF capacitance is C MIN .
  • the drive DC voltage is in the range from V MIN to V MAX
  • the contact area between the movable beam and the dielectric film changes linearly according to the drive DC voltage, and the RF capacity increases as the drive DC voltage increases.
  • V MAX the contact area between the movable beam and the dielectric film is almost maximized, and the RF capacitance is C MAX .
  • the contact area between the movable beam and the dielectric film remains almost maximized, and the RF capacitance hardly changes.
  • variable capacitance device it is desirable that the variable ratio of the RF capacitance is large. Therefore, it is desired that the CMIN, which is the RF capacitance in a state where the tip of the movable beam is in surface contact with the dielectric film, is smaller. It is desirable that C MAX, which is the RF capacity in a state where the contact area with maximizes, is larger.
  • the RF capacitor C MAX can be set to a large one by extending the line length of the electrode serving as the RF capacitor portion.
  • the RF capacitor C MIN is set depending on the line length of the electrode serving as the RF capacitor portion. I could't.
  • an object of the present invention is to provide a variable capacitance device capable of making the minimum value of the RF capacitance in a state where the movable beam is in surface contact with the dielectric film smaller than that of the conventional one.
  • the variable capacitance device of the present invention includes a support plate, a movable beam, a drive capacitance portion, and an RF capacitance portion.
  • the movable beam is supported in parallel with the main surface of the support plate.
  • the drive capacitor unit includes a pair of drive capacitor electrodes provided to be opposed to each other on the movable beam and the support plate along the main axis direction of the movable beam, and a dielectric film laminated on at least one of the drive capacitor electrodes, Consists of.
  • the drive capacity unit deforms the movable beam based on the drive capacity generated between the pair of drive capacity electrodes.
  • the RF capacitor unit includes a pair of RF capacitor electrodes provided in a long manner along the main axis direction of the movable beam so as to face the movable beam and the support plate, and a dielectric film laminated on at least one of the RF capacitor electrodes; Consists of.
  • the RF capacitor unit propagates an RF signal through an RF capacitor generated between a pair of RF capacitor electrodes.
  • the RF capacitance section has an electrode facing area, which is an area where a pair of RF capacitance electrodes face each other via a dielectric film, locally around a position where the amount of deformation in the movable beam is maximized. The configuration is reduced.
  • the area where the pair of RF capacitive electrodes are opposed to each other through the dielectric film is locally reduced around the position where the amount of deformation in the movable beam is maximized, so that the movable beam becomes dielectric.
  • the minimum value of the RF capacity generated in contact with the body membrane can be reduced.
  • the drive capacitor section of the present invention has a configuration in which the electrode facing area, which is an area where the pair of drive capacitor electrodes face each other through a dielectric film, is locally reduced around the position where the amount of deformation in the movable beam is maximized. Is preferred.
  • the minimum value of the drive capacity generated when the movable beam is in contact with the dielectric film can be reduced as in the case of the RF capacity.
  • the correlation between the capacitance change of the drive capacitance and the capacitance change of the RF capacitance increases, and it becomes easy to precisely control the RF capacitance by the drive DC voltage.
  • variable capacitance device of the present invention it is preferable that the dimension in the width direction of the RF capacitance electrode on the support plate side constituting the RF capacitance portion is locally narrow around the position where the amount of deformation in the movable beam is maximized. Further, it is preferable that the density per unit area in the dielectric film is locally small around the position where the deformation amount in the movable beam is maximized. In addition, it is preferable that the dimension in the width direction of the RF capacitive electrode on the movable beam side constituting the RF capacitive portion is locally narrow around the position where the deformation amount in the movable beam is maximized.
  • the movable beam of the present invention may have a cantilever structure supported by a support plate at one end in the main axis direction, or a double-supported beam structure supported by a support plate at both ends in the main axis direction.
  • the electrode facing area at this position is locally reduced.
  • the minimum value of the RF capacitance generated when the movable beam is in contact with the dielectric film can be reduced. This makes it possible to increase the variable ratio of the RF capacitance in the variable capacitance device.
  • variable capacitance apparatus It is a figure explaining the structural example of the conventional variable capacitance apparatus. It is a figure explaining the structural example of another variable capacity apparatus. It is a figure explaining the example of composition of the variable capacity device concerning a 1st embodiment of the present invention. It is a figure explaining the operation
  • variable capacitance apparatus It is a figure explaining the other structural example of the variable capacitance apparatus which concerns on the 3rd Embodiment of this invention. It is a figure explaining the structural example of the variable capacitance apparatus which concerns on the 4th Embodiment of this invention. It is a figure explaining the structural example of the variable capacitance apparatus which concerns on the 5th Embodiment of this invention.
  • variable capacitance device A configuration example of a variable capacitance device according to an embodiment of the present invention will be described with reference to the drawings.
  • an orthogonal coordinate XYZ axis is attached, the thickness direction of the movable beam is the Z-axis direction, the principal axis direction is the X-axis direction, and the width direction is the Y-axis direction.
  • FIG. 3A is an XY plane plan view of the variable capacitance device 1 according to the first embodiment.
  • FIG. 3B is a cross-sectional view of the variable capacitance device 1 taken along the XZ plane.
  • FIG. 3C is a YZ plane cross-sectional view of the variable capacitance device 1.
  • the variable capacitance device 1 includes a support plate 2, a movable beam 3, an upper RF capacitive electrode 6, lower RF capacitive electrodes 4A and 4B, upper drive capacitive electrodes 7A and 7B, and lower drive capacitive electrodes 5A and 5B. And a dielectric film 8.
  • the support plate 2 is made of a rectangular glass substrate in plan view.
  • the movable beam 3 is made of a high-resistance silicon substrate (insulating material), and includes two connecting portions 3B, a movable portion 3C, a support portion 3A, and a ladder portion 3D, and is a substantially L-shaped piece as viewed from the XZ plane. It is a cantilever structure.
  • the support portion 3A is long in the Y-axis direction, has a columnar shape standing from the support plate 2 in the Z-axis direction, is provided at the X-axis negative direction end of the movable beam 3, and is connected to the connecting portion 3B.
  • the movable part 3 ⁇ / b> C is supported in a state of being separated from the support plate 2.
  • the movable portion 3C has a flat plate shape that is long in the X-axis direction when viewed from the XY plane, and is provided at the end portion of the movable beam 3 in the X-axis positive direction.
  • Each of the two connecting portions 3B has a meander line shape meandering with respect to the X-axis, and is erected in the X-axis direction from both ends of the Y-axis direction of the support portion 3A so as to extend between the support portion 3A and the movable portion 3C.
  • the support end of the movable beam 3 is supported as a rotation end instead of a fixed end.
  • the movable portion 3C is partitioned into three regions arranged in the Y-axis direction by two ladder portions 3D, and each region has a flat plate shape elongated in the X-axis direction.
  • the ladder portion 3D includes a plurality of openings arranged along the X axis.
  • the lower RF capacitive electrodes 4A and 4B and the lower drive capacitive electrodes 5A and 5B are line-shaped electrodes that are formed on the upper surface of the support plate 2 and are long in the X-axis direction.
  • Lower drive capacitance electrodes 5A and 5B are arranged on both sides of 4B in the Y-axis direction.
  • the upper RF capacitive electrode 6 and the upper drive capacitive electrodes 7A and 7B are line-shaped electrodes that are formed on the lower surface of the movable beam 3 and are long in the X-axis direction.
  • the upper RF capacitive electrode 6 is the lower RF capacitive electrode.
  • the upper drive capacitance electrodes 7A and 7B are provided so as to face the lower drive capacitance electrodes 5A and 5B.
  • the dielectric film 8 is made of tantalum pentoxide, and is laminated on the upper surface region of the support plate 2 so as to cover the lower RF capacitor electrodes 4A and 4B and the lower drive capacitor electrodes 5A and 5B.
  • the lower RF capacitive electrode 4A is connected to an RF signal input terminal (or output terminal), and the lower RF capacitive electrode 4B is connected to an RF signal output terminal (or input terminal).
  • the lower drive capacitance electrodes 5A and 5B are connected to a drive DC voltage terminal via a signal cut resistance element.
  • the upper drive capacitance electrodes 7A and 7B are connected to the ground GND through signal-cutting resistive elements.
  • the lower RF capacitive electrodes 4A and 4B constitute RF capacitive portions C1A and C1B together with the opposing regions of the upper RF capacitive electrode 6 and the dielectric film 8, respectively.
  • the lower drive capacitor electrodes 5A and 5B constitute drive capacitor portions C2A and C2B together with the opposing regions of the upper drive capacitor electrodes 7A and 7B and the dielectric film 8, respectively.
  • the drive capacitors C2A and C2B serve as drive capacitors that attract the movable beam 3 to the support plate 2 side by the electrostatic attractive force and bring the movable beam 3 into contact with the dielectric film 8 from the tip (end on the X axis positive direction side). Function.
  • the RF capacitors C1A and C1B are used in a high-frequency circuit of several hundred MHz to several GHz, and function as RF capacitors whose capacitance changes depending on the contact area between the movable beam 3 and the dielectric film 8. .
  • the variable capacitance device 1 of the present embodiment has a configuration in which the width dimension of the upper RF capacitance electrode 6 is locally reduced by making the end portion in the positive direction of the X axis into a step shape.
  • the electrode facing areas in the capacitor portions C1A and C1B are locally reduced at the end portion in the positive direction of the X axis, which is the movable end of the movable beam 3.
  • FIG. 4A is a diagram for explaining changes in the contact area of the movable beam 3 with the dielectric film 8 due to the driving DC voltage
  • FIG. 4B is a graph showing the RF capacitance-driving DC voltage characteristics of the variable capacitance device 1. It is a figure which shows an example.
  • the solid line in FIG. 4B shows the characteristics of the variable capacitance device 1, and the broken line in the figure shows the characteristics of the comparative configuration in which the width dimension of the upper RF capacitive electrode 6 is made uniform.
  • the movable beam is in a state of being separated from the dielectric film in the range of the driving DC voltage from zero to V O , and the RF capacitance hardly changes even when the driving DC voltage changes.
  • the driving DC voltage V O ready to tip of the movable beam is brought into line contact with the dielectric film, RF capacity is C O.
  • the tilt angle of the movable beam with respect to the support plate changes while the tip is in line contact with the dielectric film. Almost no change.
  • the driving DC is at the voltage V MIN
  • the tip of the movable beam is in surface contact with the dielectric film, and the RF capacitance is C MIN .
  • the contact area between the movable beam and the dielectric film changes linearly according to the drive DC voltage, and as shown in FIG. 4A, the drive DC voltage increases.
  • the contact area is increased, which increases the RF capacity.
  • the drive DC voltage is V MAX
  • the contact area between the movable beam and the dielectric film is almost maximized, and the RF capacitance is C MAX .
  • the contact area between the movable beam and the dielectric film remains almost maximized, and the RF capacitance hardly changes.
  • the width dimension of the upper RF capacitive electrode 6 is reduced as described above in the region where the movable beam and the dielectric film are in contact with each other when the drive DC voltage is V O or V MIN.
  • the RF capacitance C0 and the RF capacitance CMIN are smaller than in the comparative configuration. Therefore, the gradient of the change in the RF capacitance from the drive DC voltage from V MIN to V MAX is increased, and the variable ratio of the RF capacitance can be increased.
  • FIG. 5 is an XY plane plan view of another configuration example of the variable capacitance device 1.
  • the lower RF capacitive electrodes 4A and 4B and the lower drive capacitive electrodes 5A and 5B are not shown.
  • the variable capacitance devices 1A and 1B include upper RF capacitance electrodes 6A and 6B that are different in shape from the variable capacitance device 1 described above.
  • the upper RF capacitance electrode 6A is formed in a conical shape in the vicinity of the end in the positive direction of the X axis in plan view. As shown in FIG.
  • the upper RF capacitance electrode 6B is formed in a conical shape in plan view from the end in the positive direction of the X axis to the vicinity of the center. Even with these configurations, the RF capacitance C O and the RF capacitance C MIN can be reduced. In addition, the change in the RF capacitance C MIN from the surface contact state becomes continuous, and a smoother change in the RF capacitance can be realized.
  • FIG. 6 is an XY plane plan view of the variable capacitance devices 11A and 11B according to the second embodiment.
  • the variable capacitance devices 11A and 11B include an upper RF capacitance electrode 6 and upper drive capacitance electrodes 7A and 7B having the same shape or rectangular shape as those in the first embodiment.
  • Illustration of the drive capacity electrodes 7A and 7B is omitted.
  • the variable capacitance devices 11 ⁇ / b> A and 11 ⁇ / b> B include lower RF capacitance electrodes 14 ⁇ / b> A and 14 ⁇ / b> B that are different in shape from the variable capacitance device 1 described above. As shown in FIG.
  • the lower RF capacitance electrodes 14A and 14B are stepped in a region where the movable beam 3 faces the vicinity of the end in the positive direction of the X axis in plan view. Is formed.
  • the lower RF capacitance electrodes 14A and 14B have a conical shape when the area facing the end in the positive X-axis direction of the movable beam 3 is viewed in plan view. Is formed.
  • the minimum value of the RF capacitor when the movable beam is in contact with the dielectric film can be reduced. it can.
  • the shape of the lower RF capacitive electrode is conical, so that the capacitance change of the RF capacitance can be made continuous.
  • FIG. 7 is an XY plane plan view of the variable capacitance devices 21A and 21B according to the third embodiment of the present invention.
  • the variable capacitance devices 21A and 21B include an RF capacitance electrode and a drive capacitance electrode having the same shape or rectangular shape as those in the first or second embodiment. In the figure, the RF capacitance electrode and the drive capacitance electrode are illustrated. Is omitted.
  • the variable capacitance devices 21A and 21B include dielectric films 28A and 28B whose shapes are different from those of the above-described embodiment.
  • the dielectric films 28 ⁇ / b> A and 28 ⁇ / b> B have a configuration in which a plurality of grooves are provided in a region facing the X-axis positive direction end of the movable beam 3.
  • the dimension in the Y-axis direction of each groove may be longer for the groove on the tip side in the positive direction of the X axis and shorter for the groove on the negative side of the X axis.
  • FIG. 8 is a YZ plane sectional view showing another configuration example of the variable capacitance devices 21A and 21B according to the third embodiment of the present invention.
  • the depth in the Z-axis direction of the groove portion of the dielectric film described above may leave the dielectric film at the bottom of the groove portion as shown in FIG. 8A, as shown in FIG.
  • the lower RF capacitive electrodes 4A and 4B may be configured to be exposed at the bottom of the groove.
  • the minimum value of the RF capacity when the movable beam is in contact with the dielectric film can be reduced.
  • FIG. 9A is an XY plane plan view of the variable capacitance device 31 according to the fourth embodiment.
  • the variable capacitance device 31 includes a dielectric film 38 having a shape different from that of the above-described embodiment, and has a configuration in which a plurality of groove portions are provided in the dielectric film 38 not only in the RF capacitance portion but also in the drive capacitance portion.
  • FIG. 9B is a diagram showing the RF capacitance-drive DC voltage characteristics in the variable capacitance device 31. The broken line in the figure indicates the characteristic of the variable capacitance device 1 described above, and the solid line in the figure indicates the characteristic of the variable capacitance device 31.
  • the electrode facing area is reduced not only in the RF capacitor unit but also in the drive capacitor unit, and the minimum value of the RF capacitor when the movable beam is in contact with the dielectric film is reduced.
  • the correlation between the capacitance change of the drive capacitance and the capacitance change of the RF capacitance is increased, and the capacitance change in the vicinity of the RF capacitance CMIN when the movable beam comes into surface contact can be smoothed.
  • FIG. 10A is an XY plane plan view of the variable capacitance device 41 according to the fifth embodiment.
  • the variable capacitance device 41 is different from the above-described embodiment in that it includes a movable beam 43 having a doubly supported beam configuration.
  • the upper RF capacitance electrode 46 is arranged in the Y-axis direction. It has a step shape with reduced width. Even with such a configuration, it is possible to increase the variable ratio of the RF capacitance by reducing the RF capacitance in the region where the upper RF capacitive electrode first makes line contact or surface contact with the dielectric film. become.
  • the RF capacitance is reduced by changing the shape of the lower RF capacitive electrode and the dielectric film instead of the upper RF capacitive electrode as shown in the second to third embodiments. May be adopted.
  • FIG. 10B is an XY plane plan view of another configuration example of the variable capacitance device 41 according to the fifth embodiment.
  • This variable capacity device 41 has a configuration in which a meander-shaped connecting and fixing portion 43A is provided at the end of the movable beam in the X-axis positive direction, and the spring constant of the connecting and fixing portion 43A is the spring constant of the connecting portion 3B in the X-axis negative direction.
  • the movable beam 43 comes into contact with the dielectric film from the end in the positive direction of the X axis.
  • the movable beam comes into contact with the dielectric film not from the periphery of the central region of the movable beam but from the end in the positive direction of the X axis even in the double-supported beam structure.
  • FIG. 10C is an XY plane plan view of another configuration example of the variable capacitance device 41 according to the fifth embodiment.
  • the variable capacitance device 41 includes a connecting portion 43B having a high-rigidity beam-like portion extending along the X-axis and a low-rigidity meander-like portion, and the meander-like portion in the X-axis positive direction of the movable beam. It is the structure which connects to an edge part and connects a beam-shaped part to 3 A of support parts. Even in this configuration, the movable beam comes into contact with the dielectric film not from the central region of the movable beam but around the end in the positive direction of the X axis even in the case of the double-supported beam structure. By reducing the electrode facing area of the RF capacitor in the region around the end, it is possible to increase the variable ratio of the RF capacitor.

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Abstract

Provided is a variable capacitance device in which the minimum RF capacitance when the movable beam is in contact with the dielectric film can be made smaller than was previously possible. The variable capacitance device (1) includes a support plate (2), a movable beam (3), drive capacitor sections (C2A, C2B), and RF capacitor sections (C1A, C1B). The movable beam (3) is cantilevered in parallel with the principal surface of the support plate (2). Each drive capacitor section (C2A, C2B), as well as each RF capacitor section (C1A, C1B), is made up of: a pair of drive capacitor electrodes, or a pair of RF capacitor electrodes, that are provided so as to respectively face the movable beam (3) and the support plate (2) lengthwise along the direction of the principal axis of the movable beam (3); and a dielectric film (8) provided between the electrodes. Each RF capacitor section (C1A, C1B) has a structure in which the area defined by the pair of RF capacitor electrodes opposing one another across the dielectric film (8) is locally reduced in the periphery of the movable end of the movable beam (3).

Description

可変容量装置Variable capacity device
　この発明は、静電力により駆動するＭＥＭＳを用いてＲＦ（Ｒａｄｉｏ　Ｆｒｅｑｕｅｎｃｙ）容量を変えることができる可変容量装置に関するものである。 The present invention relates to a variable capacity device capable of changing an RF (Radio Frequency) capacity using a MEMS driven by an electrostatic force.
　近年、可変容量装置に静電力により駆動するＭＥＭＳが利用されることがある（特許文献１，２参照。）。 In recent years, MEMS driven by electrostatic force is sometimes used for variable capacitance devices (see Patent Documents 1 and 2).
　図１は、従来の可変容量装置の構成例を説明する図である。
　可変容量装置１０１は、可動板１０２，１０３を備える。可動板１０２，１０３はそれぞれ両持ち梁構造であり、導電性材料からなる。可動板１０２と可動板１０３とは、互いに間隔を隔てて配置されている。可動板１０３は、可動板１０２との対向面が凸形状であり、誘電体層１０４を表面に備える。可動板１０２，１０３間に駆動ＤＣ電圧を印加することで生じる駆動容量によって、可動板１０２，１０３間の間隔が狭まって可動板１０３の凸形状先端領域から可動板１０２に誘電体層１０４を介して接触し、接触面積に応じて可変容量装置１０１のＲＦ容量が変わる。 FIG. 1 is a diagram illustrating a configuration example of a conventional variable capacitance device.
The variable capacity device 101 includes movable plates 102 and 103. The movable plates 102 and 103 each have a doubly supported beam structure and are made of a conductive material. The movable plate 102 and the movable plate 103 are spaced apart from each other. The movable plate 103 has a convex surface facing the movable plate 102 and includes a dielectric layer 104 on the surface. The distance between the movable plates 102 and 103 is narrowed by the driving capacity generated by applying the driving DC voltage between the movable plates 102 and 103, and the dielectric layer 104 is passed from the convex tip region of the movable plate 103 to the movable plate 102. The RF capacity of the variable capacitance device 101 changes according to the contact area.
特開２００６－２１０８４３号公報Japanese Patent Laid-Open No. 2006-210843 特開２００８－１８２１３４号公報JP 2008-182134 A
　従来の可変容量装置では、駆動ＤＣ電圧とＲＦ信号とが共通する電極に印加されるため、直流成分と交流成分とを分離するための抵抗やコンデンサが駆動回路に必要であった。抵抗やコンデンサの挿入によって回路構成の複雑化と挿入損失の増大が引き起こされるため、本願出願人はそのような抵抗やコンデンサが不要な可変容量装置の開発を行っている。図２（Ａ）はその可変容量装置２０１の構成例を示す平面図であり、図２（Ｂ）はその側面断面図である。
　可変容量装置２０１は、支持板２０２と可動梁２０３とを備える。可動梁２０３は、支持板２０２に対して平行に支持される片持ち梁構造である。支持板２０２には、可動梁２０３の主軸方向に沿う直線線路状の電極２０４が平行に２つ設けられているとともに、コの字線路状の電極２０５が支持板２０２の両端部の間に電極２０４を挟むように設けられており、さらに、電極２０４および電極２０５それぞれを覆うように誘電体膜２０８Ａ，２０８Ｂが設けられている。また、可動梁２０３には、２つの電極２０４に対向する１つの矩形状の電極２０６（図２（Ｂ）に図示する。）と、電極２０５に対向するコの字線路状の電極２０７（図２（Ｂ）に図示する。）とが設けられている。電極２０４と電極２０６とは、誘電体膜２０８Ａを介して対向してＲＦ容量部として機能し、電極２０５と電極２０７とは、誘電体膜２０８Ｂを介して対向して駆動容量部として機能する。駆動容量部は駆動ＤＣ電圧が印加されることで生じる駆動容量によって、静電引力で可動梁２０３を変形させる。ＲＦ容量部は、電極２０４を高周波回路に接続することによって、容量を変えることができるＲＦ容量として利用される。このように可変容量装置２０１は、駆動ＤＣ電圧が印加される電極２０５，２０７と、ＲＦ信号が印加される電極２０４，２０６とを構造的に分離した構成である。 In the conventional variable capacitance device, since the driving DC voltage and the RF signal are applied to the common electrode, a resistor and a capacitor for separating the direct current component and the alternating current component are required for the driving circuit. Since insertion of a resistor or a capacitor causes a complicated circuit configuration and an increase in insertion loss, the applicant of the present application has developed a variable capacitance device that does not require such a resistor or capacitor. 2A is a plan view showing a configuration example of the variable capacitance device 201, and FIG. 2B is a side sectional view thereof.
The variable capacity device 201 includes a support plate 202 and a movable beam 203. The movable beam 203 has a cantilever structure that is supported in parallel to the support plate 202. The support plate 202 is provided with two linear line-shaped electrodes 204 in parallel along the main axis direction of the movable beam 203, and the U-shaped line-shaped electrodes 205 are disposed between both ends of the support plate 202. In addition, dielectric films 208A and 208B are provided so as to cover the electrodes 204 and 205, respectively. In addition, the movable beam 203 includes one rectangular electrode 206 (shown in FIG. 2B) facing the two electrodes 204 and a U-shaped electrode 207 facing the electrode 205 (see FIG. 2B). 2 (B).). The electrode 204 and the electrode 206 are opposed to each other via the dielectric film 208A and function as an RF capacitor portion, and the electrode 205 and the electrode 207 are opposed to each other via the dielectric film 208B and function as a drive capacitor portion. The drive capacity unit deforms the movable beam 203 by electrostatic attraction by a drive capacity generated by applying a drive DC voltage. The RF capacitor unit is used as an RF capacitor whose capacitance can be changed by connecting the electrode 204 to a high frequency circuit. As described above, the variable capacitance device 201 has a structure in which the electrodes 205 and 207 to which the driving DC voltage is applied and the electrodes 204 and 206 to which the RF signal is applied are structurally separated.
　図２（Ｃ）は、上述のような構成の可変容量装置における駆動ＤＣ電圧－ＲＦ容量特性の典型例を示す図である。
　駆動ＤＣ電圧がゼロからＶＯまでの範囲では、可動梁は誘電体膜から離間した状態であり駆動ＤＣ電圧が変化してもＲＦ容量は殆ど変化しない。駆動ＤＣ電圧がＶＯでは、可動梁の先端が誘電体膜に線接触する状態になり、ＲＦ容量がＣＯとなる。駆動ＤＣ電圧がＶＯからＶＭＩＮまでの範囲では、可動梁は先端が誘電体膜に線接触する状態で支持板に対する傾斜角が変化し、その間は駆動ＤＣ電圧が変化してもＲＦ容量は殆ど変化しない。駆動ＤＣ電圧がＶＭＩＮでは、可動梁の先端が誘電体膜に面接触する状態になり、ＲＦ容量がＣＭＩＮとなる。駆動ＤＣ電圧がＶＭＩＮからＶＭＡＸまでの範囲では、可動梁と誘電体膜との接触面積が駆動ＤＣ電圧に応じて線形変化し、駆動ＤＣ電圧の増加につれてＲＦ容量が増加する。駆動ＤＣ電圧ＶＭＡＸでは、可動梁と誘電体膜との接触面積がほぼ最大化した状態になり、ＲＦ容量がＣＭＡＸとなる。駆動ＤＣ電圧がＶＭＡＸを超えても、可動梁と誘電体膜との接触面積はほぼ最大化した状態のままであり、ＲＦ容量は殆ど変化しなくなる。 FIG. 2C is a diagram showing a typical example of driving DC voltage-RF capacitance characteristics in the variable capacitance device having the above-described configuration.
When the driving DC voltage is in the range from zero to V O , the movable beam is in a state of being separated from the dielectric film, and the RF capacitance hardly changes even if the driving DC voltage changes. The driving DC voltage V O, ready to tip of the movable beam is brought into line contact with the dielectric film, RF capacity is C O. In the range of the driving DC voltage from V O to V MIN , the tilt angle of the movable beam with respect to the support plate changes while the tip is in line contact with the dielectric film. Almost no change. When the driving DC voltage is V MIN , the tip of the movable beam is in surface contact with the dielectric film, and the RF capacitance is C MIN . When the drive DC voltage is in the range from V MIN to V MAX , the contact area between the movable beam and the dielectric film changes linearly according to the drive DC voltage, and the RF capacity increases as the drive DC voltage increases. At the drive DC voltage V MAX , the contact area between the movable beam and the dielectric film is almost maximized, and the RF capacitance is C MAX . Even when the drive DC voltage exceeds V MAX , the contact area between the movable beam and the dielectric film remains almost maximized, and the RF capacitance hardly changes.
　可変容量装置ではＲＦ容量の可変比が大きいほうが望ましいため、可動梁の先端が誘電体膜に面接触する状態でのＲＦ容量であるＣＭＩＮはより小さいことが望まれ、可動梁と誘電体膜との接触面積が最大化する状態でのＲＦ容量であるＣＭＡＸはより大きいことが望まれる。ＲＦ容量ＣＭＡＸについては、ＲＦ容量部となる電極の線路長を伸長することで大きなものに設定することができるが、ＲＦ容量ＣＭＩＮについては、ＲＦ容量部となる電極の線路長によっては設定することができなかった。 In the variable capacitance device, it is desirable that the variable ratio of the RF capacitance is large. Therefore, it is desired that the CMIN, which is the RF capacitance in a state where the tip of the movable beam is in surface contact with the dielectric film, is smaller. It is desirable that C MAX, which is the RF capacity in a state where the contact area with maximizes, is larger. The RF capacitor C MAX can be set to a large one by extending the line length of the electrode serving as the RF capacitor portion. The RF capacitor C MIN is set depending on the line length of the electrode serving as the RF capacitor portion. I couldn't.
　そこで本発明の目的は、可動梁が誘電体膜に面接触する状態でのＲＦ容量の最小値を従来よりも小さくすることができる可変容量装置を提供することにある。 Therefore, an object of the present invention is to provide a variable capacitance device capable of making the minimum value of the RF capacitance in a state where the movable beam is in surface contact with the dielectric film smaller than that of the conventional one.
　この発明の可変容量装置は、支持板と可動梁と駆動容量部とＲＦ容量部とを備える。可動梁は支持板の主面に平行に支持される。駆動容量部は、可動梁の主軸方向に沿って長尺に可動梁と支持板とに互いに対向して設けられる一対の駆動容量電極と、駆動容量電極の少なくとも一方に積層される誘電体膜とからなる。駆動容量部は、一対の駆動容量電極の間に生じる駆動容量に基づいて可動梁を変形させる。ＲＦ容量部は、可動梁の主軸方向に沿って長尺に可動梁と支持板とに互いに対向して設けられる一対のＲＦ容量電極と、ＲＦ容量電極の少なくとも一方に積層される誘電体膜とからなる。ＲＦ容量部は、一対のＲＦ容量電極の間に生じるＲＦ容量を介してＲＦ信号を伝搬させる。このような可変容量装置において、ＲＦ容量部は、誘電体膜を介して一対のＲＦ容量電極が対向する面積である電極対向面積を、可動梁における変形量が最大となる位置周辺で局所的に低減した構成である。
　この構成では、可動梁における変形量が最大となる位置周辺で、誘電体膜を介して一対のＲＦ容量電極が対向する面積である電極対向面積を局所的に低減することで、可動梁が誘電体膜に接触した状態で生じるＲＦ容量の最小値を小さくすることができる。 The variable capacitance device of the present invention includes a support plate, a movable beam, a drive capacitance portion, and an RF capacitance portion. The movable beam is supported in parallel with the main surface of the support plate. The drive capacitor unit includes a pair of drive capacitor electrodes provided to be opposed to each other on the movable beam and the support plate along the main axis direction of the movable beam, and a dielectric film laminated on at least one of the drive capacitor electrodes, Consists of. The drive capacity unit deforms the movable beam based on the drive capacity generated between the pair of drive capacity electrodes. The RF capacitor unit includes a pair of RF capacitor electrodes provided in a long manner along the main axis direction of the movable beam so as to face the movable beam and the support plate, and a dielectric film laminated on at least one of the RF capacitor electrodes; Consists of. The RF capacitor unit propagates an RF signal through an RF capacitor generated between a pair of RF capacitor electrodes. In such a variable capacitance device, the RF capacitance section has an electrode facing area, which is an area where a pair of RF capacitance electrodes face each other via a dielectric film, locally around a position where the amount of deformation in the movable beam is maximized. The configuration is reduced.
In this configuration, the area where the pair of RF capacitive electrodes are opposed to each other through the dielectric film is locally reduced around the position where the amount of deformation in the movable beam is maximized, so that the movable beam becomes dielectric. The minimum value of the RF capacity generated in contact with the body membrane can be reduced.
　この発明の駆動容量部は、可動梁における変形量が最大となる位置周辺で誘電体膜を介して一対の駆動容量電極が対向する面積である電極対向面積を局所的に低減した構成であると好適である。
　この構成では、ＲＦ容量と同様に、可動梁が誘電体膜に接触した状態で生じる駆動容量の最小値を小さくすることができる。これにより、駆動容量の容量変化とＲＦ容量の容量変化との相関性が高まり、駆動ＤＣ電圧によるＲＦ容量の制御を精緻に行うことが容易になる。 The drive capacitor section of the present invention has a configuration in which the electrode facing area, which is an area where the pair of drive capacitor electrodes face each other through a dielectric film, is locally reduced around the position where the amount of deformation in the movable beam is maximized. Is preferred.
In this configuration, the minimum value of the drive capacity generated when the movable beam is in contact with the dielectric film can be reduced as in the case of the RF capacity. As a result, the correlation between the capacitance change of the drive capacitance and the capacitance change of the RF capacitance increases, and it becomes easy to precisely control the RF capacitance by the drive DC voltage.
　この発明の可変容量装置は、ＲＦ容量部を構成する支持板側のＲＦ容量電極における幅方向の寸法が、可動梁における変形量が最大となる位置周辺で局所的に狭いと好適である。また、誘電体膜における単位面積当たり密度が、可動梁における変形量が最大となる位置周辺で局所的に小さいと好適である。また、ＲＦ容量部を構成する可動梁側のＲＦ容量電極における幅方向の寸法が、可動梁における変形量が最大となる位置周辺で局所的に狭いと好適である。 In the variable capacitance device of the present invention, it is preferable that the dimension in the width direction of the RF capacitance electrode on the support plate side constituting the RF capacitance portion is locally narrow around the position where the amount of deformation in the movable beam is maximized. Further, it is preferable that the density per unit area in the dielectric film is locally small around the position where the deformation amount in the movable beam is maximized. In addition, it is preferable that the dimension in the width direction of the RF capacitive electrode on the movable beam side constituting the RF capacitive portion is locally narrow around the position where the deformation amount in the movable beam is maximized.
　この発明の可動梁は、主軸方向の一端で支持板に支持される片持ち梁構造であってもよく、主軸方向の両端で支持板に支持される両持ち梁構造であってもよい。 The movable beam of the present invention may have a cantilever structure supported by a support plate at one end in the main axis direction, or a double-supported beam structure supported by a support plate at both ends in the main axis direction.
　この発明によれば、片持ち梁構造または両持ち梁構造の可動梁において変形量が最大となる位置が最初に誘電体膜に接触するので、この位置での電極対向面積を局所的に小さくすることにより、可動梁が誘電体膜に接触した状態で生じるＲＦ容量の最小値を小さくすることができる。これにより、可変容量装置におけるＲＦ容量の可変比を大きくすることが可能になる。 According to the present invention, since the position where the amount of deformation is maximum first contacts the dielectric film in the movable beam having the cantilever structure or the double-supported structure, the electrode facing area at this position is locally reduced. As a result, the minimum value of the RF capacitance generated when the movable beam is in contact with the dielectric film can be reduced. This makes it possible to increase the variable ratio of the RF capacitance in the variable capacitance device.
従来の可変容量装置の構成例を説明する図である。It is a figure explaining the structural example of the conventional variable capacitance apparatus. 他の可変容量装置の構成例を説明する図である。It is a figure explaining the structural example of another variable capacity apparatus. 本発明の第１の実施形態に係る可変容量装置の構成例を説明する図である。It is a figure explaining the example of composition of the variable capacity device concerning a 1st embodiment of the present invention. 本発明の第１の実施形態に係る可変容量装置の駆動時の動作を説明する図である。It is a figure explaining the operation | movement at the time of the drive of the variable capacitance apparatus which concerns on the 1st Embodiment of this invention. 本発明の第１の実施形態に係る可変容量装置の他の構成例を説明する図である。It is a figure explaining the other structural example of the variable capacitance apparatus which concerns on the 1st Embodiment of this invention. 本発明の第２の実施形態に係る可変容量装置の構成例を説明する図である。It is a figure explaining the structural example of the variable capacitance apparatus which concerns on the 2nd Embodiment of this invention. 本発明の第３の実施形態に係る可変容量装置の構成例を説明する図である。It is a figure explaining the structural example of the variable capacitance apparatus which concerns on the 3rd Embodiment of this invention. 本発明の第３の実施形態に係る可変容量装置の他の構成例を説明する図である。It is a figure explaining the other structural example of the variable capacitance apparatus which concerns on the 3rd Embodiment of this invention. 本発明の第４の実施形態に係る可変容量装置の構成例を説明する図である。It is a figure explaining the structural example of the variable capacitance apparatus which concerns on the 4th Embodiment of this invention. 本発明の第５の実施形態に係る可変容量装置の構成例を説明する図である。It is a figure explaining the structural example of the variable capacitance apparatus which concerns on the 5th Embodiment of this invention.
　本発明の実施形態に係る可変容量装置の構成例について、図を参照して説明する。なお、各図には直交座標形のＸ－Ｙ－Ｚ軸を付し、可動梁の厚み方向をＺ軸方向、主軸方向をＸ軸方向、幅方向をＹ軸方向とする。 A configuration example of a variable capacitance device according to an embodiment of the present invention will be described with reference to the drawings. In each figure, an orthogonal coordinate XYZ axis is attached, the thickness direction of the movable beam is the Z-axis direction, the principal axis direction is the X-axis direction, and the width direction is the Y-axis direction.
《第１の実施形態》
　図３（Ａ）は、第１の実施形態に係る可変容量装置１のＸ－Ｙ面平面図である。図３（Ｂ）は、可変容量装置１のＸ－Ｚ面断面図である。図３（Ｃ）は、可変容量装置１のＹ－Ｚ面断面図である。 << First Embodiment >>
FIG. 3A is an XY plane plan view of the variable capacitance device 1 according to the first embodiment. FIG. 3B is a cross-sectional view of the variable capacitance device 1 taken along the XZ plane. FIG. 3C is a YZ plane cross-sectional view of the variable capacitance device 1.
　可変容量装置１は、支持板２と、可動梁３と、上側ＲＦ容量電極６と、下側ＲＦ容量電極４Ａ，４Ｂと、上側駆動容量電極７Ａ，７Ｂと、下側駆動容量電極５Ａ，５Ｂと、誘電体膜８とを備える。
　支持板２は、平面視して矩形状のガラス基板からなる。
　可動梁３は高抵抗シリコン基板（絶縁材料）からなり、２本の連結部３Ｂと可動部３Ｃと支持部３Ａとラダー部３Ｄとを備え、Ｘ－Ｚ面を視て略Ｌ字状の片持ち梁構造である。支持部３Ａは、Ｙ軸方向に長尺であって、支持板２からＺ軸方向に立設する柱状であり、可動梁３のＸ軸負方向端部に設けられていて、連結部３Ｂと可動部３Ｃとを支持板２から離間した状態で支持する。可動部３Ｃは、Ｘ－Ｙ面を視てＸ軸方向に長尺な平板状であり、可動梁３のＸ軸正方向端部に設けられている。２本の連結部３Ｂは、それぞれＸ軸に対して蛇行するミアンダライン状であり、支持部３ＡのＹ軸方向両端からＸ軸方向に立設して支持部３Ａと可動部３Ｃとの間を接続し、可動梁３の支持端を固定端ではなく回転端として支持する。
　可動部３Ｃは、２本のラダー部３ＤによってＹ軸方向に並ぶ３つの領域に区画されていて、各領域はＸ軸方向に長尺な平板状となっている。ラダー部３Ｄは、Ｘ軸に沿って配列される複数の開口部を備える。 The variable capacitance device 1 includes a support plate 2, a movable beam 3, an upper RF capacitive electrode 6, lower RF capacitive electrodes 4A and 4B, upper drive capacitive electrodes 7A and 7B, and lower drive capacitive electrodes 5A and 5B. And a dielectric film 8.
The support plate 2 is made of a rectangular glass substrate in plan view.
The movable beam 3 is made of a high-resistance silicon substrate (insulating material), and includes two connecting portions 3B, a movable portion 3C, a support portion 3A, and a ladder portion 3D, and is a substantially L-shaped piece as viewed from the XZ plane. It is a cantilever structure. The support portion 3A is long in the Y-axis direction, has a columnar shape standing from the support plate 2 in the Z-axis direction, is provided at the X-axis negative direction end of the movable beam 3, and is connected to the connecting portion 3B. The movable part 3 </ b> C is supported in a state of being separated from the support plate 2. The movable portion 3C has a flat plate shape that is long in the X-axis direction when viewed from the XY plane, and is provided at the end portion of the movable beam 3 in the X-axis positive direction. Each of the two connecting portions 3B has a meander line shape meandering with respect to the X-axis, and is erected in the X-axis direction from both ends of the Y-axis direction of the support portion 3A so as to extend between the support portion 3A and the movable portion 3C. The support end of the movable beam 3 is supported as a rotation end instead of a fixed end.
The movable portion 3C is partitioned into three regions arranged in the Y-axis direction by two ladder portions 3D, and each region has a flat plate shape elongated in the X-axis direction. The ladder portion 3D includes a plurality of openings arranged along the X axis.
　下側ＲＦ容量電極４Ａ，４Ｂと下側駆動容量電極５Ａ，５Ｂとは、それぞれ支持板２の上面に形成されたＸ軸方向に長尺な線路状電極であり、下側ＲＦ容量電極４Ａ，４ＢのＹ軸方向の両脇に下側駆動容量電極５Ａ，５Ｂが配置されている。上側ＲＦ容量電極６と上側駆動容量電極７Ａ，７Ｂとは、それぞれ可動梁３の下面に形成されたＸ軸方向に長尺な線路状電極であり、上側ＲＦ容量電極６は下側ＲＦ容量電極４Ａ，４Ｂに対向するように設けられており、上側駆動容量電極７Ａ，７Ｂは下側駆動容量電極５Ａ，５Ｂに対向するように設けられている。誘電体膜８は、五酸化タンタルからなり、下側ＲＦ容量電極４Ａ，４Ｂと下側駆動容量電極５Ａ，５Ｂとを覆うように、支持板２の上面領域に積層されている。下側ＲＦ容量電極４ＡはＲＦ信号の入力端子（または出力端子）に接続され、下側ＲＦ容量電極４ＢはＲＦ信号の出力端子（または入力端子）に接続されている。下側駆動容量電極５Ａ，５Ｂは、信号カット用の抵抗素子を介して駆動ＤＣ電圧端子に接続されている。上側駆動容量電極７Ａ，７Ｂは、信号カット用の抵抗素子を介してグランドＧＮＤに接続されている。
　このため、下側ＲＦ容量電極４Ａ，４Ｂは、それぞれ上側ＲＦ容量電極６および誘電体膜８の対向する領域とともにＲＦ容量部Ｃ１Ａ，Ｃ１Ｂを構成している。下側駆動容量電極５Ａ，５Ｂは、それぞれ上側駆動容量電極７Ａ，７Ｂおよび誘電体膜８の対向する領域とともに駆動容量部Ｃ２Ａ，Ｃ２Ｂを構成している。 The lower RF capacitive electrodes 4A and 4B and the lower drive capacitive electrodes 5A and 5B are line-shaped electrodes that are formed on the upper surface of the support plate 2 and are long in the X-axis direction. Lower drive capacitance electrodes 5A and 5B are arranged on both sides of 4B in the Y-axis direction. The upper RF capacitive electrode 6 and the upper drive capacitive electrodes 7A and 7B are line-shaped electrodes that are formed on the lower surface of the movable beam 3 and are long in the X-axis direction. The upper RF capacitive electrode 6 is the lower RF capacitive electrode. The upper drive capacitance electrodes 7A and 7B are provided so as to face the lower drive capacitance electrodes 5A and 5B. The dielectric film 8 is made of tantalum pentoxide, and is laminated on the upper surface region of the support plate 2 so as to cover the lower RF capacitor electrodes 4A and 4B and the lower drive capacitor electrodes 5A and 5B. The lower RF capacitive electrode 4A is connected to an RF signal input terminal (or output terminal), and the lower RF capacitive electrode 4B is connected to an RF signal output terminal (or input terminal). The lower drive capacitance electrodes 5A and 5B are connected to a drive DC voltage terminal via a signal cut resistance element. The upper drive capacitance electrodes 7A and 7B are connected to the ground GND through signal-cutting resistive elements.
For this reason, the lower RF capacitive electrodes 4A and 4B constitute RF capacitive portions C1A and C1B together with the opposing regions of the upper RF capacitive electrode 6 and the dielectric film 8, respectively. The lower drive capacitor electrodes 5A and 5B constitute drive capacitor portions C2A and C2B together with the opposing regions of the upper drive capacitor electrodes 7A and 7B and the dielectric film 8, respectively.
　駆動容量部Ｃ２Ａ，Ｃ２Ｂは、その静電引力により可動梁３を支持板２側に引き付け、可動梁３を先端（Ｘ軸正方向側の端部）から誘電体膜８に接触させる駆動容量として機能する。駆動ＤＣ電圧が高電圧であるほど、可動梁３と誘電体膜８との接触面積は大きくなる。
　ＲＦ容量部Ｃ１Ａ，Ｃ１Ｂは、数百MHz～数GHzの高周波回路の中で使用され、可動梁３と誘電体膜８との接触面積に応じて容量の大きさが変化するＲＦ容量として機能する。 The drive capacitors C2A and C2B serve as drive capacitors that attract the movable beam 3 to the support plate 2 side by the electrostatic attractive force and bring the movable beam 3 into contact with the dielectric film 8 from the tip (end on the X axis positive direction side). Function. The higher the driving DC voltage is, the larger the contact area between the movable beam 3 and the dielectric film 8 is.
The RF capacitors C1A and C1B are used in a high-frequency circuit of several hundred MHz to several GHz, and function as RF capacitors whose capacitance changes depending on the contact area between the movable beam 3 and the dielectric film 8. .
　本実施形態の可変容量装置１においては、前述の上側ＲＦ容量電極６における幅寸法を、Ｘ軸正方向の端部を段形状にすることで局所的に低減した構成であり、これにより、ＲＦ容量部Ｃ１Ａ，Ｃ１Ｂにおける電極対向面積を、可動梁３の可動端であるＸ軸正方向の端部で局所的に低減している。このような構成とすることにより、上側ＲＦ容量電極６が誘電体膜８に線接触または面接触する際のＲＦ容量を低減できる。 The variable capacitance device 1 of the present embodiment has a configuration in which the width dimension of the upper RF capacitance electrode 6 is locally reduced by making the end portion in the positive direction of the X axis into a step shape. The electrode facing areas in the capacitor portions C1A and C1B are locally reduced at the end portion in the positive direction of the X axis, which is the movable end of the movable beam 3. With this configuration, it is possible to reduce the RF capacitance when the upper RF capacitive electrode 6 is in line contact or surface contact with the dielectric film 8.
　図４（Ａ）は可動梁３における誘電体膜８との接触面積の駆動ＤＣ電圧による変化を説明する図であり、図４（Ｂ）は可変容量装置１におけるＲＦ容量－駆動ＤＣ電圧特性の一例を示す図である。 FIG. 4A is a diagram for explaining changes in the contact area of the movable beam 3 with the dielectric film 8 due to the driving DC voltage, and FIG. 4B is a graph showing the RF capacitance-driving DC voltage characteristics of the variable capacitance device 1. It is a figure which shows an example.
図４（Ｂ）中の実線が可変容量装置１での特性を示し、図中の破線は上側ＲＦ容量電極６の幅寸法を一様にした比較構成での特性を示している。 The solid line in FIG. 4B shows the characteristics of the variable capacitance device 1, and the broken line in the figure shows the characteristics of the comparative configuration in which the width dimension of the upper RF capacitive electrode 6 is made uniform.
　本構成および比較構成はいずれも、駆動ＤＣ電圧がゼロからＶＯまでの範囲では、可動梁は誘電体膜から離間した状態であり、駆動ＤＣ電圧が変化してもＲＦ容量は殆ど変化しない。駆動ＤＣ電圧がＶＯでは、可動梁の先端が誘電体膜に線接触する状態になり、ＲＦ容量がＣＯとなる。駆動ＤＣ電圧がＶＯからＶＭＩＮまでの範囲では、可動梁は先端が誘電体膜に線接触する状態で支持板に対する傾斜角が変化し、その間は駆動ＤＣ電圧が変化してもＲＦ容量は殆ど変化しない。駆動ＤＣが電圧ＶＭＩＮでは、可動梁の先端が誘電体膜に面接触する状態になり、ＲＦ容量がＣＭＩＮとなる。駆動ＤＣ電圧がＶＭＩＮからＶＭＡＸまでの範囲では、可動梁と誘電体膜との接触面積が駆動ＤＣ電圧に応じて線形変化し、図４（Ａ）に示すように駆動ＤＣ電圧の増加につれて接触面積が増大し、これによりＲＦ容量が増加する。駆動ＤＣ電圧がＶＭＡＸでは、可動梁と誘電体膜との接触面積がほぼ最大化した状態になり、ＲＦ容量がＣＭＡＸとなる。駆動ＤＣ電圧がＶＭＡＸを超えても、可動梁と誘電体膜との接触面積はほぼ最大化した状態のままであり、ＲＦ容量は殆ど変化しなくなる。 In both this configuration and the comparison configuration, the movable beam is in a state of being separated from the dielectric film in the range of the driving DC voltage from zero to V O , and the RF capacitance hardly changes even when the driving DC voltage changes. The driving DC voltage V O, ready to tip of the movable beam is brought into line contact with the dielectric film, RF capacity is C O. In the range of the driving DC voltage from V O to V MIN , the tilt angle of the movable beam with respect to the support plate changes while the tip is in line contact with the dielectric film. Almost no change. When the driving DC is at the voltage V MIN , the tip of the movable beam is in surface contact with the dielectric film, and the RF capacitance is C MIN . When the drive DC voltage is in the range from V MIN to V MAX , the contact area between the movable beam and the dielectric film changes linearly according to the drive DC voltage, and as shown in FIG. 4A, the drive DC voltage increases. The contact area is increased, which increases the RF capacity. When the drive DC voltage is V MAX , the contact area between the movable beam and the dielectric film is almost maximized, and the RF capacitance is C MAX . Even when the drive DC voltage exceeds V MAX , the contact area between the movable beam and the dielectric film remains almost maximized, and the RF capacitance hardly changes.
　本構成では、駆動ＤＣ電圧がＶＯ又はＶＭＩＮの状態で可動梁と誘電体膜とが接触する領域において、前述のように上側ＲＦ容量電極６の幅寸法が低減されているため、本構成でのＲＦ容量ＣＯおよびＲＦ容量ＣＭＩＮは比較構成よりも小さくなる。そのため、駆動ＤＣ電圧がＶＭＩＮからＶＭＡＸまでのＲＦ容量の変化の傾きが大きくなり、ＲＦ容量の可変比を大きくすることが可能になる。 In this configuration, the width dimension of the upper RF capacitive electrode 6 is reduced as described above in the region where the movable beam and the dielectric film are in contact with each other when the drive DC voltage is V O or V MIN. The RF capacitance C0 and the RF capacitance CMIN are smaller than in the comparative configuration. Therefore, the gradient of the change in the RF capacitance from the drive DC voltage from V MIN to V MAX is increased, and the variable ratio of the RF capacitance can be increased.
　次に、第１の実施形態に係る可変容量装置の他の構成例を説明する。図５は、可変容量装置１の他の構成例のＸ－Ｙ面平面図である。なお、同図中では下側ＲＦ容量電極４Ａ，４Ｂと下側駆動容量電極５Ａ，５Ｂとの図示を省いている。
　この可変容量装置１Ａ，１Ｂは、前述の可変容量装置１とは形状が相違する上側ＲＦ容量電極６Ａ，６Ｂを備える。図５（Ａ）に示すように、可変容量装置１Ａでは、上側ＲＦ容量電極６Ａは、Ｘ軸正方向の端部近傍が平面視して錐状に形成されている。図５（Ｂ）に示すように、可変容量装置１Ｂでは、上側ＲＦ容量電極６Ｂは、Ｘ軸正方向の端部から中央部付近まで平面視して錐状に形成されている。これらの構成でもＲＦ容量ＣＯおよびＲＦ容量ＣＭＩＮを小さくすることができる。その上、面接触する状態からのＲＦ容量ＣＭＩＮの変化が連続的になり、より滑らかなＲＦ容量の変化を実現することが可能になる。 Next, another configuration example of the variable capacitance device according to the first embodiment will be described. FIG. 5 is an XY plane plan view of another configuration example of the variable capacitance device 1. In the figure, the lower RF capacitive electrodes 4A and 4B and the lower drive capacitive electrodes 5A and 5B are not shown.
The variable capacitance devices 1A and 1B include upper RF capacitance electrodes 6A and 6B that are different in shape from the variable capacitance device 1 described above. As shown in FIG. 5A, in the variable capacitance device 1A, the upper RF capacitance electrode 6A is formed in a conical shape in the vicinity of the end in the positive direction of the X axis in plan view. As shown in FIG. 5B, in the variable capacitance device 1B, the upper RF capacitance electrode 6B is formed in a conical shape in plan view from the end in the positive direction of the X axis to the vicinity of the center. Even with these configurations, the RF capacitance C O and the RF capacitance C MIN can be reduced. In addition, the change in the RF capacitance C MIN from the surface contact state becomes continuous, and a smoother change in the RF capacitance can be realized.
《第２の実施形態》
　図６は、第２の実施形態に係る可変容量装置１１Ａ，１１ＢのＸ－Ｙ面平面図である。なお、可変容量装置１１Ａ，１１Ｂは第１の実施形態と同形状または矩形状の上側ＲＦ容量電極６と上側駆動容量電極７Ａ，７Ｂとを備えるが、同図中では上側ＲＦ容量電極６と上側駆動容量電極７Ａ，７Ｂとの図示を省いている。
　可変容量装置１１Ａ，１１Ｂは、前述の可変容量装置１とは形状が相違する下側ＲＦ容量電極１４Ａ，１４Ｂを備える。図６（Ａ）に示すように、可変容量装置１１Ａでは、下側ＲＦ容量電極１４Ａ，１４Ｂは、可動梁３におけるＸ軸正方向の端部近傍と対面する領域が平面視して段状に形成されている。図６（Ｂ）に示すように、可変容量装置１１Ｂでは、下側ＲＦ容量電極１４Ａ，１４Ｂは、可動梁３におけるＸ軸正方向の端部近傍と対面する領域が平面視して錐状に形成されている。
　これらの構成のように、下側ＲＦ容量電極の形状によってＲＦ容量部の電極対向面積を低減しても、可動梁が誘電体膜に接触する状態でのＲＦ容量の最小値を小さくすることができる。そして、上側ＲＦ容量電極の場合と同様に下側ＲＦ容量電極の形状を錐状にすることで、ＲＦ容量の容量変化を連続的にすることができる。 << Second Embodiment >>
FIG. 6 is an XY plane plan view of the variable capacitance devices 11A and 11B according to the second embodiment. The variable capacitance devices 11A and 11B include an upper RF capacitance electrode 6 and upper drive capacitance electrodes 7A and 7B having the same shape or rectangular shape as those in the first embodiment. In FIG. Illustration of the drive capacity electrodes 7A and 7B is omitted.
The variable capacitance devices 11 </ b> A and 11 </ b> B include lower RF capacitance electrodes 14 </ b> A and 14 </ b> B that are different in shape from the variable capacitance device 1 described above. As shown in FIG. 6A, in the variable capacitance device 11A, the lower RF capacitance electrodes 14A and 14B are stepped in a region where the movable beam 3 faces the vicinity of the end in the positive direction of the X axis in plan view. Is formed. As shown in FIG. 6 (B), in the variable capacitance device 11B, the lower RF capacitance electrodes 14A and 14B have a conical shape when the area facing the end in the positive X-axis direction of the movable beam 3 is viewed in plan view. Is formed.
As in these configurations, even if the electrode facing area of the RF capacitor portion is reduced due to the shape of the lower RF capacitor electrode, the minimum value of the RF capacitor when the movable beam is in contact with the dielectric film can be reduced. it can. Then, similarly to the case of the upper RF capacitive electrode, the shape of the lower RF capacitive electrode is conical, so that the capacitance change of the RF capacitance can be made continuous.
《第３の実施形態》
　図７は、本発明の第３の実施形態に係る可変容量装置２１Ａ，２１ＢのＸ－Ｙ面平面図である。なお、可変容量装置２１Ａ，２１Ｂは第１または第２の実施形態と同形状または矩形状のＲＦ容量電極と駆動容量電極とを備えるが、同図中ではＲＦ容量電極と駆動容量電極との図示を省いている。
　可変容量装置２１Ａ，２１Ｂは、前述の実施形態とは形状が相違する誘電体膜２８Ａ，２８Ｂを備える。誘電体膜２８Ａ，２８Ｂは、可動梁３のＸ軸正方向端部と対向する領域に複数の溝部を設けた構成である。なお誘電体膜２８Ｂのように、各溝部のＹ軸方向の寸法を、Ｘ軸正方向先端側の溝部ほど長く、Ｘ軸負方向側の溝部ほど短く構成してもよい。 << Third Embodiment >>
FIG. 7 is an XY plane plan view of the variable capacitance devices 21A and 21B according to the third embodiment of the present invention. The variable capacitance devices 21A and 21B include an RF capacitance electrode and a drive capacitance electrode having the same shape or rectangular shape as those in the first or second embodiment. In the figure, the RF capacitance electrode and the drive capacitance electrode are illustrated. Is omitted.
The variable capacitance devices 21A and 21B include dielectric films 28A and 28B whose shapes are different from those of the above-described embodiment. The dielectric films 28 </ b> A and 28 </ b> B have a configuration in which a plurality of grooves are provided in a region facing the X-axis positive direction end of the movable beam 3. As in the dielectric film 28B, the dimension in the Y-axis direction of each groove may be longer for the groove on the tip side in the positive direction of the X axis and shorter for the groove on the negative side of the X axis.
　図８は、本発明の第３の実施形態に係る可変容量装置２１Ａ，２１Ｂの他の構成例を示すＹ－Ｚ面断面図である。前述の誘電体膜の溝部のＺ軸方向の深さは、図８（Ａ）に示すように、溝部の底部分に誘電体膜を残すようにしてもよく、図８（Ｂ）に示すように、溝部の底部分に下側ＲＦ容量電極４Ａ，４Ｂが露出するように構成してもよい。
　これらの構成のように、誘電体膜の形状によってＲＦ容量部の電極対向面積を低減しても、可動梁が誘電体膜に接触する状態でのＲＦ容量の最小値を低減することができる。いずれの構成であっても、可動梁の先端ほどＲＦ容量が小さくなるように勾配をつけることで、ＲＦ容量の容量変化を連続的にすることが可能になる。 FIG. 8 is a YZ plane sectional view showing another configuration example of the variable capacitance devices 21A and 21B according to the third embodiment of the present invention. The depth in the Z-axis direction of the groove portion of the dielectric film described above may leave the dielectric film at the bottom of the groove portion as shown in FIG. 8A, as shown in FIG. In addition, the lower RF capacitive electrodes 4A and 4B may be configured to be exposed at the bottom of the groove.
As in these configurations, even if the electrode facing area of the RF capacitor portion is reduced depending on the shape of the dielectric film, the minimum value of the RF capacity when the movable beam is in contact with the dielectric film can be reduced. In any configuration, it is possible to continuously change the capacitance of the RF capacitance by providing a gradient so that the RF capacitance becomes smaller at the tip of the movable beam.
《第４の実施形態》
　図９（Ａ）は、第４の実施形態に係る可変容量装置３１のＸ－Ｙ面平面図である。可変容量装置３１は、前述の実施形態とは形状が相違する誘電体膜３８を備え、ＲＦ容量部だけでなく、駆動容量部でも誘電体膜３８に複数の溝部を設けた構成である。
　図９（Ｂ）は、可変容量装置３１におけるＲＦ容量－駆動ＤＣ電圧特性を示す図である。図中の破線は前述の可変容量装置１の特性を示し、図中の実線は可変容量装置３１の特性を示している。
　本実施形態ではＲＦ容量部だけでなく駆動容量部でも電極対向面積を低減し、可動梁が誘電体膜に接触する状態でのＲＦ容量の最小値を低減する。この場合、駆動容量の容量変化とＲＦ容量の容量変化との相関性が高まり、可動梁が面接触する際のＲＦ容量ＣＭＩＮ近傍での容量変化を滑らかにすることができる。 << Fourth Embodiment >>
FIG. 9A is an XY plane plan view of the variable capacitance device 31 according to the fourth embodiment. The variable capacitance device 31 includes a dielectric film 38 having a shape different from that of the above-described embodiment, and has a configuration in which a plurality of groove portions are provided in the dielectric film 38 not only in the RF capacitance portion but also in the drive capacitance portion.
FIG. 9B is a diagram showing the RF capacitance-drive DC voltage characteristics in the variable capacitance device 31. The broken line in the figure indicates the characteristic of the variable capacitance device 1 described above, and the solid line in the figure indicates the characteristic of the variable capacitance device 31.
In the present embodiment, the electrode facing area is reduced not only in the RF capacitor unit but also in the drive capacitor unit, and the minimum value of the RF capacitor when the movable beam is in contact with the dielectric film is reduced. In this case, the correlation between the capacitance change of the drive capacitance and the capacitance change of the RF capacitance is increased, and the capacitance change in the vicinity of the RF capacitance CMIN when the movable beam comes into surface contact can be smoothed.
《第５の実施形態》
　図１０（Ａ）は、第５の実施形態に係る可変容量装置４１のＸ－Ｙ面平面図である。可変容量装置４１は両持ち梁構成の可動梁４３を備える点で上述の実施形態と相違し、ここでは可動梁４３における変位が最も大きい中央領域近傍において、上側ＲＦ容量電極４６のＹ軸方向の幅寸法を低減した段形状としている。このような構成であっても、やはり最初に上側ＲＦ容量電極が誘電体膜に線接触、または面接触する領域でのＲＦ容量を低減することで、ＲＦ容量の可変比を大きくすることが可能になる。
　なお、本実施形態の構成で、上述の第２乃至第３の実施形態に示したような上側ＲＦ容量電極ではなく下側ＲＦ容量電極や誘電体膜の形状変更により、ＲＦ容量を低減する構造を採用しても良い。 << Fifth Embodiment >>
FIG. 10A is an XY plane plan view of the variable capacitance device 41 according to the fifth embodiment. The variable capacitance device 41 is different from the above-described embodiment in that it includes a movable beam 43 having a doubly supported beam configuration. Here, in the vicinity of the central region where the displacement of the movable beam 43 is the largest, the upper RF capacitance electrode 46 is arranged in the Y-axis direction. It has a step shape with reduced width. Even with such a configuration, it is possible to increase the variable ratio of the RF capacitance by reducing the RF capacitance in the region where the upper RF capacitive electrode first makes line contact or surface contact with the dielectric film. become.
In the configuration of the present embodiment, the RF capacitance is reduced by changing the shape of the lower RF capacitive electrode and the dielectric film instead of the upper RF capacitive electrode as shown in the second to third embodiments. May be adopted.
　図１０（Ｂ）は、第５の実施形態に係る可変容量装置４１の他の構成例のＸ－Ｙ面平面図である。この可変容量装置４１は可動梁におけるＸ軸正方向の端部にミアンダ状の連結固定部４３Ａを設けた構成であり、連結固定部４３Ａのバネ定数をＸ軸負方向の連結部３Ｂのバネ定数よりも大幅に小さくし、これにより可動梁４３がＸ軸正方向の端部から誘電体膜に接触するようにした構成である。
　このような構成においては、両持ち梁構造ではあっても可動梁の中央領域周辺ではなくＸ軸正方向の端部周辺から可動梁が誘電体膜に接触するようになるので、このＸ軸正方向の端部周辺の領域でＲＦ容量部の電極対向面積を低減することで、やはりＲＦ容量の可変比を大きくすることが可能になる。 FIG. 10B is an XY plane plan view of another configuration example of the variable capacitance device 41 according to the fifth embodiment. This variable capacity device 41 has a configuration in which a meander-shaped connecting and fixing portion 43A is provided at the end of the movable beam in the X-axis positive direction, and the spring constant of the connecting and fixing portion 43A is the spring constant of the connecting portion 3B in the X-axis negative direction. In this configuration, the movable beam 43 comes into contact with the dielectric film from the end in the positive direction of the X axis.
In such a configuration, the movable beam comes into contact with the dielectric film not from the periphery of the central region of the movable beam but from the end in the positive direction of the X axis even in the double-supported beam structure. By reducing the electrode facing area of the RF capacitor portion in the region around the end portion in the direction, it is possible to increase the variable ratio of the RF capacitor.
　図１０（Ｃ）は、第５の実施形態に係る可変容量装置４１の他の構成例のＸ－Ｙ面平面図である。この可変容量装置４１は、Ｘ軸に沿って延設する高剛性の梁状部分と、低剛性のミアンダ状部分とを有する連結部４３Ｂを備え、ミアンダ状部分を可動梁におけるＸ軸正方向の端部に接続し、梁状部分を支持部３Ａに接続する構成である。この構成においても、両持ち梁構造ではあっても可動梁の中央領域周辺ではなくＸ軸正方向の端部周辺から可動梁が誘電体膜に接触するようになるので、このＸ軸正方向の端部周辺の領域でＲＦ容量部の電極対向面積を低減することで、やはりＲＦ容量の可変比を大きくすることが可能になる。 FIG. 10C is an XY plane plan view of another configuration example of the variable capacitance device 41 according to the fifth embodiment. The variable capacitance device 41 includes a connecting portion 43B having a high-rigidity beam-like portion extending along the X-axis and a low-rigidity meander-like portion, and the meander-like portion in the X-axis positive direction of the movable beam. It is the structure which connects to an edge part and connects a beam-shaped part to 3 A of support parts. Even in this configuration, the movable beam comes into contact with the dielectric film not from the central region of the movable beam but around the end in the positive direction of the X axis even in the case of the double-supported beam structure. By reducing the electrode facing area of the RF capacitor in the region around the end, it is possible to increase the variable ratio of the RF capacitor.
　以上の各実施形態で説明したように本発明は実施できるが、本発明の範囲は上述の実施形態の記載に制限されるものではなく、本発明の範囲は特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図されるものである。 As described in the above embodiments, the present invention can be implemented, but the scope of the present invention is not limited to the description of the above-described embodiments, and the scope of the present invention is indicated by the claims, and It is intended that all modifications within the meaning and scope equivalent to the terms of the claims are included.
Ｃ１Ａ，Ｃ１Ｂ…ＲＦ容量部
Ｃ２Ａ，Ｃ２Ｂ…駆動容量部
１，１１，２１，３１，４１…可変容量装置
２…支持板
３，４３…可動梁
３Ａ，４３Ａ…支持部
３Ｂ，４３Ｂ…連結部
３Ｃ…可動部
３Ｄ…ラダー部
４Ａ，４Ｂ，１４Ａ，１４Ｂ…下側ＲＦ容量電極
５Ａ，５Ｂ…下側駆動容量電極
６，６Ａ，６Ｂ，４６…上側ＲＦ容量電極
７Ａ，７Ｂ…上側駆動容量電極
８，２８，３８…誘電体膜 C1A, C1B... RF capacitor section C2A, C2B... Drive capacitor section 1, 11, 21, 31, 41... Variable capacity device 2... Support plate 3, 43. ... movable part 3D ... ladder parts 4A, 4B, 14A, 14B ... lower RF capacitive electrodes 5A, 5B ... lower drive capacitive electrodes 6, 6A, 6B, 46 ... upper RF capacitive electrodes 7A, 7B ... upper drive capacitive electrode 8 , 28, 38 ... Dielectric film

Claims (7)

  1. 　支持板と、
    　前記支持板の主面に平行に支持される可動梁と、
    　前記可動梁の主軸方向に沿って長尺に前記可動梁と前記支持板とに互いに対向して設けられる一対の駆動容量電極と、駆動容量電極の少なくとも一方に積層される誘電体膜とからなり、前記一対の駆動容量電極の間に生じる駆動容量に基づいて前記可動梁を変形させる駆動容量部と、
    　前記可動梁の主軸方向に沿って長尺に前記可動梁と前記支持板とに互いに対向して設けられる一対のＲＦ容量電極と、ＲＦ容量電極の少なくとも一方に積層される誘電体膜とからなり、前記一対のＲＦ容量電極の間に生じるＲＦ容量を介してＲＦ信号を伝搬させるＲＦ容量部と、
    　を備え、
    　前記ＲＦ容量部は、前記誘電体膜を介して前記一対のＲＦ容量電極が対向する面積である電極対向面積を、前記可動梁における変形量が最大となる位置周辺で局所的に低減した構成である、可変容量装置。     A support plate;
    A movable beam supported parallel to the main surface of the support plate;
    A pair of drive capacitor electrodes provided to be opposed to each other on the movable beam and the support plate along the main axis direction of the movable beam, and a dielectric film laminated on at least one of the drive capacitor electrodes. A drive capacity unit that deforms the movable beam based on a drive capacity generated between the pair of drive capacity electrodes;
    A pair of RF capacitive electrodes provided to be opposed to each other on the movable beam and the support plate along the main axis direction of the movable beam, and a dielectric film laminated on at least one of the RF capacitive electrodes. An RF capacitor unit for propagating an RF signal through an RF capacitor generated between the pair of RF capacitor electrodes;
    With
    The RF capacitor unit has a configuration in which an electrode facing area, which is an area where the pair of RF capacitor electrodes face each other through the dielectric film, is locally reduced around a position where the amount of deformation in the movable beam is maximized. There is a variable capacity device.
  2. 　前記駆動容量部は、可動梁における変形量が最大となる位置周辺で前記誘電体膜を介して前記一対の駆動容量電極が対向する面積である電極対向面積を局所的に低減した構成である、請求項１に記載の可変容量装置。 The drive capacitor section has a configuration in which an electrode facing area, which is an area where the pair of drive capacitor electrodes face each other via the dielectric film, is locally reduced around a position where the amount of deformation in the movable beam is maximized. The variable capacitance device according to claim 1.
  3. 　前記ＲＦ容量部を構成する支持板側のＲＦ容量電極における幅方向の寸法が、前記可動梁における変形量が最大となる位置周辺で局所的に狭い、請求項１または２に記載の可変容量装置。 3. The variable capacitance device according to claim 1, wherein a dimension in a width direction of an RF capacitance electrode on a support plate side constituting the RF capacitance portion is locally narrow around a position where a deformation amount in the movable beam is maximized. .
  4. 　前記誘電体膜における単位面積当たり密度が、前記可動梁における変形量が最大となる位置周辺で局所的に低減する、請求項１～３のいずれかに記載の可変容量装置。 4. The variable capacitance device according to claim 1, wherein the density per unit area in the dielectric film is locally reduced around a position where the amount of deformation in the movable beam is maximized.
  5. 　前記ＲＦ容量部を構成する可動梁側のＲＦ容量電極における幅方向の寸法が、前記可動梁における変形量が最大となる位置周辺で局所的に狭い、請求項１～４のいずれかに記載の可変容量装置。 The dimension in the width direction of the RF capacitive electrode on the movable beam side constituting the RF capacitive section is locally narrow around a position where the amount of deformation in the movable beam is maximized. Variable capacity device.
  6. 　前記可動梁は、主軸方向の一端で前記支持板に支持される片持ち梁構造である、請求項１～５のいずれかに記載の可変容量装置。 The variable capacity device according to any one of claims 1 to 5, wherein the movable beam has a cantilever structure supported by the support plate at one end in a main axis direction.
  7. 　前記可動梁は、主軸方向の両端で前記支持板に支持される両持ち梁構造である、請求項１～５のいずれかに記載の可変容量装置。 The variable capacity device according to any one of claims 1 to 5, wherein the movable beam has a double-supported beam structure supported by the support plate at both ends in a main axis direction.
PCT/JP2011/061924 2010-06-14 2011-05-25 Variable capacitance device WO2011158619A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10149950A (en) * 1996-11-15 1998-06-02 Murata Mfg Co Ltd Variable capacitance capacitor
JP2006165380A (en) * 2004-12-09 2006-06-22 Kyocera Corp Variable capacitor
JP2008005642A (en) * 2006-06-23 2008-01-10 Toshiba Corp Piezoelectric-driving mems actuator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10149950A (en) * 1996-11-15 1998-06-02 Murata Mfg Co Ltd Variable capacitance capacitor
JP2006165380A (en) * 2004-12-09 2006-06-22 Kyocera Corp Variable capacitor
JP2008005642A (en) * 2006-06-23 2008-01-10 Toshiba Corp Piezoelectric-driving mems actuator

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