Abstract: A MEMS tunable capacitor and method of fabricating the same, includes a plurality of fixed charge plates on a substrate, the plurality of fixed charge plates having a same height, being arranged in a shape of comb-teeth and being electrically connected to one another, a capacitor dielectric layer covering the plurality of fixed charge plates, a movable charge plate structure spaced apart from the capacitor dielectric layer, and arranged on the plurality of fixed charge plates, wherein the movable charge plate structure includes a plurality of movable charge plates arranged corresponding the plurality of fixed charge plates, and an actuator connected to the movable charge plate structure allowing the movable charge plate structure to move in a horizontal direction.

Abstract: A variable-capacitance element includes: a first electrode and a second electrode which are fixed on a substrate with a spacing; a movable electrode; an actuator which is supported on a supporting portion provided on the substrate to drive the movable electrode. The movable electrode is put in an electrically connecting state with the second electrode, when the movable electrode is driven to a first position by the actuator, and the movable electrode is put in an electrically non-connected state with the second electrode, when the movable electrode is driven to a second position by the actuator. The movable electrode is constituted to be always put in an electrically non-connected state with the first electrode.

Abstract: A device for varying the capacitance of an electronic circuit is disclosed. The device comprises a flexible membrane located above the electronic circuit, a metal layer connected to the flexible membrane, and bias circuitry located above the membrane. Variation of the capacitance of the electronic circuit is obtained by pulling the membrane upwards by means of the bias circuitry. The disclosed device provides a sizeable capacitance variation and high Q factor, resulting in overall low filter insertion loss. A nearly constant group delay over a wide operating bandwidth is also obtained.

Abstract: A varactor includes a container forming a liquid chamber, a first electrode mounted adjacent the chamber, and a second electrode mounted adjacent the chamber. The chamber may be sized and configured, and a spacing between the electrodes and the chamber may be selected, so that a contact angle of a quantity of liquid metal in the chamber relative to at least one of the electrodes can be changed by applying a bias voltage.

Abstract: A piezoelectric spatial light modulator including a substrate having an array of cavities and piezoelectric cantilevers is arranged on the substrate. Each of the piezoelectric cantilevers includes a base portion on the substrate and a beam portion extending over a respective one of the cavities. Each of the piezoelectric cantilevers further includes a first electrode, a second electrode and a piezoelectric element between the electrodes. A flexible layer covers the cavities and the piezoelectric cantilevers and reflective elements are each located on the flexible layer over a respective one of the beam portions.

Abstract: A variable capacitance capacitor has a plurality of variable capacitance elements, using a thin-film dielectric layer whose dielectric constant varies with voltage application, connected in series with one another between the high-frequency signal input and output terminals. The first bias lines belonging to a high-potential side and the second bias lines belonging to a low-potential side, in terms of voltage application, are connected, alternately, to electrodes of the variable capacitance elements connected one another and electrodes in the array of the series-connected variable capacitance elements connected respectively to the input terminal and the output terminal.

Abstract: A charge control circuit for controlling a micro-electromechanical system (MEMS) device having variable capacitor formed by first conductive plate and a second conductive plate separated by a variable gap distance. The charge control circuit comprises a switch circuit configured to receive a reference voltage having a selected voltage level and configured to respond to an enable signal having a duration at least as long as an electrical time constant constant of the MEMS device, but shorter than a mechanical time constant of the MEMS device, to apply the selected voltage level across the first and second plates for the duration to thereby cause a stored charge having a desired magnitude to accumulate on the variable capacitor, wherein the variable gap distance is a function of the magnitude of the stored charge.

Abstract: A MEMS tunable capacitor with angular vertical comb-drive (AVC) actuators is described where high capacitances and a wide continuous tuning range is achieved in a compact space. The comb fingers rotate through a small vertical angle which allows a wider tuning range than in conventional lateral comb drive devices. Fabrication of the device is straightforward, and involves a single deep reactive ion etching step followed by release and out-of-plane assembly of the angular combs.

Abstract: A device for varying the capacitance of an electronic circuit is disclosed. The device comprises a flexible membrane located above the electronic circuit, a metal layer connected to the flexible membrane, and bias circuitry located above the membrane. Variation of the capacitance of the electronic circuit is obtained by pulling the membrane upwards by means of the bias circuitry. The disclosed device provides a sizeable capacitance variation and high Q factor, resulting in overall low filter insertion loss. A nearly constant group delay over a wide operating bandwidth is also obtained.

Abstract: A variable capacitor having a groove portion formed in an insulating substrate, two upper portions of the substrate located on either side of the groove portion forming two lateral edges, a conductive layer covering the inside of the groove portion, a flexible conductive membrane, placed above the groove portion by bearing on the edges, a dielectric layer covering the conductive layer or the membrane to insulate the conductive layer and the membrane, and terminals of application of a voltage between the conductive layer and the membrane, and such that the depth of the groove portion continuously increases from one of the edges to the bottom of the groove portion, and that the conductive layer covers the inside of the groove portion at least to reach one of the two edges, that it may cover.

Abstract: The disclosure describes a variable capacitor device, which is formed by a linear motor and a variable capacitor having at least one stator electrode and a movable electrode. A piezoelectric transducer of the linear motor is frictionally coupled to the movable electrode. Application of electrical signals to the piezoelectric transducer of the linear motor produces a motion of the surface of the piezoelectric transducer. The frictional coupling between the piezoelectric transducer surface and the movable electrode transmits a fraction of piezoelectric transducer motion to the movable piston electrode thereby changing the capacity of the variable capacitor. The amount and sign of the capacitance change is selectable by the operator through control of the electrical signals applied to the piezoelectric transducer.

Abstract: A capacitive light/dimmer switch which uses soft or fuzzy fabrics made with electronic textiles instead of, or as an extension of, metal or plastic plates. The soft fabric material, which may be in the form of a pompom, tassel, fur, or other electronic trim element, provides an attractive and compelling user interface that is soft to the touch. The user simply touches the pompom, as he would the dimmer plate, to cause the amount of light to increase or decrease. The electronic textiles of the light controller comprise electrodes integrated into their yarns or fibers, resulting in a conductive material (electronic textile) that may be used as the user interface. This conductive material is electrically connected to a sensing circuit by either AC coupling or DC contact. When the user touches the conductive material, the sensing circuit measures the change in load of the electrodes, and the lighting is changed.

Abstract: A variable capacitance element includes a movable element provided above a substrate using supporting portions and support beams so as to be displaced from the substrate. An insulating film and a movable electrode are provided on a conductor facing surface of the movable element. A driving electrode is arranged to displace the movable element, between a signal cutoff position and a signal passage position, whereby a high frequency signal transmitted through a transmission line is cut off or allowed to pass. The insulating film uses compressive stress to warp the movable element and the movable electrode in a direction of warping in a convex form toward the transmission line, and maintains this warping direction.

Abstract: A vacuum variable capacitor is includes of a vacuum container which is formed by sealing both end of a cylindrical insulator with a fixed-side end plate and a movable-side end plate, a movable conductive member which is disposed opposite to the fixed-side end plate in the vacuum container, a fixed electrode which is provided on the fixed-side end plate, a movable electrode which is provided on the movable conductive member, a bellows provided in the vacuum container, a rotating portion which is rotatably disposed outside of the vacuum container, and a ball screw through which the movable conductive member is supported by the rotating member.

Abstract: Tunable capacitors (10, 20, 30, 40) have a dielectric material (16, 26, 36, 42) between electrodes, which dielectric material comprises an insulating material (17, 27, 37, 42) and electrically conductive material, (18, 28, 38, 48) e.g., conductive nanoparticulates, dispersed therein. In certain cases, enhanced tune-ability is achieved when the dielectric material comprises elongated nanoparticulates (38). Further enhanced tune-ability may be achieved by aligning elongated particulates in an electrode-to-electrode direction. Nanoparticulates may be produced by heating passivated nanoparticulates. Passivated nanoparticulates may be covalently bound within a polymeric matrix. High bias potential device structures can be formed with preferential mobilities.

Abstract: A variable capacitance element includes a coplanar line or signal conduction and a movable body, which are vertically displaced through a supporting bar and which are provided on a substrate. A movable electrode is provided between a first driving electrode and second and third driving electrodes which are movable electrodes. Voltage is applied between the movable electrodes, such that one of the movable electrodes is pressed against the coplanar line through a dielectric film. Thus, high frequency signals conducting through the coplanar line are shut off. When voltage is applied between the other electrodes, the movable electrode and the dielectric film are moved apart from the coplanar line. Thus, high frequency signals are conducted through the coplanar line.

Abstract: The present invention is directed to a capacitor apparatus of the capacity variable type. This capacitor apparatus is manufactured by Micro Electro-Mechanical System technology, and comprises an insulating substrate (2) in which at least two capacitor electrodes (3), (4) are formed on one surface (2a) in the state where they are insulated each other, an actuator (5) formed by insulating material and having an external shape to bridge over the respective capacitor electrodes (3), (4), the actuator (5) being such that a conductor which respectively constitutes capacitors between the conductor (6) and these capacitor electrodes (3), (4), and drive means (7) for allowing this actuator (5) to undergo an operation to come into contact with one principal surface (2a) of the insulating substrate (2) or to become away therefrom.

Abstract: A P type substrate is provided on a surface thereof with varactor elements. The varactor element has an N well formed on the surface of the P type substrate, and a gate insulating film is formed on the N well, with a polysilicon layer formed further thereon. On the other hand, the varactor element has an N well formed on the surface of the P type substrate, and a gate insulating film, greater than the gate insulating film in thickness, is formed on the N well. The polysilicon layer is then formed on the gate insulating film. Furthermore, the polysilicon layer is connected to a gate terminal, while the N well is connected to an S/D terminal via N+ diffusion layers.

Abstract: A tunable capacitor includes a substrate, a stationary electrode and a movable electrode supported by the substrate, piezoelectric actuators that are supported by the substrate and drive the movable electrode, and a dielectric layer interposed between the stationary electrode and the movable electrode.

Abstract: A sensor for determining the presence of an analyte is disclosed comprising a reactive layer disposed between a base plate and a movable plate. The reactive layer is configured to interact with an analyte effecting a change in capacitance between the base plate and movable plate. When the analyte has a polarity or overall Hildebrand solubility parameter that is similar to the reactive layer, the change in capacitance is caused by a swelling of the reactive layer as analyte is absorbed into the reactive layer. This results in a decrease in capacitance. When the analyte has a solubility parameter not near the reactive layer, the absorbed analyte causes the reactive layer's total polarity to increase, an effect that dominates swelling. This causes an increase in capacitance. A capacitive sensing circuit is included for measuring the change in capacitance which is indicative of the analyte exposed to the sensor.

Abstract: A vacuum variable capacitor includes an energization bellows arranged in a vacuum vessel and having ends mounted to a movable-electrode support plate and a movable side-end plate, respectively, a heat shielding bellows arranged inside the energization bellows and outside a slide-guide support and having ends mounted to the movable-electrode support plate and the movable side-end plate, respectively, and a cooling pipe interposed between the two bellows and for preventing transfer of heat generated in the energization bellows.

Abstract: A variable capacitor includes a stator and a rotor rotatably supported by a cover relative to the stator. The stator includes a first stator electrode of two or more layers and a second stator electrode of two or more layers in the interior of a dielectric substrate. The first stator electrode is connected to a first external electrode and the second stator electrode is connected to a second external electrode. The rotor includes a rotor electrode of two pieces opposing the stator electrodes, and capacitances are defined in the areas of overlap of the rotor electrode and stator electrodes. The capacitances are adjustable to extremely small levels.

Abstract: The present invention is directed to a capacitor apparatus of the capacity variable type. This capacitor apparatus is manufactured by Micro Electro-Mechanical System technology, and comprises an insulating substrate (2) in which at least two capacitor electrodes (3), (4) are formed on one surface (2a) in the state where they are insulated each other, an actuator (5) formed by insulating material and having an external shape to bridge over the respective capacitor electrodes (3), (4), the actuator (5) being such that a conductor which respectively constitutes capacitors between the conductor (6) and these capacitor electrodes (3), (4), and drive means (7) for allowing this actuator (5) to undergo an operation to come into contact with one principal surface (2a) of the insulating substrate (2) or to become away therefrom.

Abstract: The present invention is directed to a capacitor apparatus of the capacity variable type. This capacitor apparatus is manufactured by Micro Electro-Mechanical System technology, and comprises an insulating substrate (2) in which at least two capacitor electrodes (3), (4) are formed on one surface (2a) in the state where they are insulated each other, an actuator (5) formed by insulating material and having an external shape to bridge over the respective capacitor electrodes (3), (4), the actuator (5) being such that a conductor which respectively constitutes capacitors between the conductor (6) and these capacitor electrodes (3), (4), and drive means (7) for allowing this actuator (5) to undergo an operation to come into contact with one principal surface (2a) of the insulating substrate (2) or to become away therefrom.

Abstract: Various embodiments of tunable capacitors are disclosed. One embodiment is in the form of a tunable capacitor (368) having a pair of stationary capacitor electrodes (392) that are fixed to and disposed the same distance above a substrate (388) in the vertical dimension. A tuning element (416) is suspended above the substrate (388) by an elevation system (460) that accommodates movement of the tuning element (416) in the vertical dimension. Changing the capacitance of the tunable capacitor (368) is accomplished by moving the tuning element (416) in the vertical dimension.

Abstract: A variable capacitor is provided such that it is possible to make nonlinear distortion small and use at high power handling capability, and such that a variable rate of capacitance is not influenced by a high-frequency voltage substantially. A variable capacitor is used by changing capacitance through application across electrodes of direct current voltage and high-frequency voltage. When an effective voltage value of high-frequency voltage is within a range of voltage values of direct current voltage, there is substantially no fluctuation caused by application of high-frequency voltage with respect to a change of capacitance caused by application of direct current. Since it is possible to decrease susceptibility to the high-frequency voltage of the variable capacitor, it is possible to obtain a variable capacitor such that nonlinear distortion is small and power handling capability is high.

Abstract: A tunable element in the microwave frequency range is described that may include one or more tunable elements that are directly digitally controlled by a digital bus connecting a digital control circuit to each controlled element. In particular, each digital signal is filtered by a digital isolation technique so that the signal reaches the tunable elements with very low noise. The low noise digital signals are then converted to analog control voltages. The direct D/A conversion is accomplished by a special D/A converter which is manufactured as an integral part of a substrate. This D/A converter in accordance with the invention may consist of a resistor ladder or a directly digitally controlled capacitor. The direct digitally controlled capacitor may be a cantilevered type capacitor having multiple separate electrodes or sub-plates representing binary bits that may be used to control the capacitor.

Abstract: A new type of high-Q variable capacitor includes a substrate, a first electrically conductive layer fixed to the substrate, a dielectric layer fixed to a portion of the electrically conductive layer, and a second electrically conductive layer having an anchor portion and a free portion. The anchor portion is fixed to the dielectric layer and the free portion is initially fixed to the dielectric layer, but is released from the dielectric layer to become separated from the dielectric layer, and wherein an inherent stress profile in the second electrically conductive layer biases the free portion away from the dielectric layer. When a bias voltage is applied between the first electrically conductive layer and the second electrically conductive layer, electrostatic forces in the free portion bend the free portion towards the first electrically conductive layer, thereby increasing the capacitance of the capacitor.

Abstract: The invention relates to a variable capacitor which, due to its particular arrangement of electrodes, enables a significantly higher current flow than generally known constructions having the same or a similar structural shape, said capacitor also has an increased life expectancy and is compatible with existing capacitors in terms of connection. Such variable capacitors can be used in high frequency generators, in matchboxes and in interface networks for industrial high frequency applications, as regulatable filters in high frequency power electronics and in the power part of emission installations.

Abstract: A variable capacitor device using MEMS or micromachining techniques wherein thin-films of materials are deposited, patterned and etched to form movable micromechanical elements on the surface of a substrate composed of either semiconductor, glass, metal, or ceramic material. In one embodiment of the present invention to achieve higher frequency performance as well as other benefits, the substrate is comprised of Low-Temperature Co-Fired Ceramics (LTCC). The variable capacitor is an electrostatically actuated micromechanical device and if fabricated on a LTCC multi-layered substrate material has continuous electrical connections through the layers. The same LTCC substrate material can also be used to enclose the device by selectively removing a portion of the upper substrate so as to form a cavity. The two substrates are then bonded together to enclose and protect the variable capacitor.

Abstract: A three-dimensional micro electro-mechanical (MEMS) variable capacitor is described wherein movable comb electrodes of opposing polarity are fabricated simultaneously on the same substrate are independently actuated. These electrodes are formed in an interdigitated fashion to maximize the capacitance of the device. The electrodes are jointly or individually actuated. A separate actuation electrode and a ground plane electrode actuate the movable electrodes. The voltage potential between the two electrodes provides a primary mode of operation of the device. The variation of the sidewall overlap area between the interdigitated fingers provides the expected capacitance tuning of the device. The interdigitated electrodes can also be attached on both ends to form fixed-fixed beams. The stiffness of the electrodes is reduced by utilizing thin support structures at the ends of the electrodes. The three dimensional aspect of the device avails large surface area.

Abstract: An integrated, tunable capacitance is specified in which the quality factor is improved by virtue of the fact that, instead of source/drain regions, provision is made of highly doped well terminal regions having a deep depth, for example formed as collector deep implantation regions. This reduces the series resistance of the tunable capacitance. The integrated, tunable capacitance can be used for example in integrated voltage-controlled oscillator circuits in which a high quality factor is demanded.

Abstract: Variable capacitive device, such as a capacitor, controllable in voltage Vc including at least one first armature (L) and one second armature (R), the armatures being separated by an insulation layer (D) including several conducting aggregates separated from each other. The use of the capacitor according to the invention in a resonant circuit.

Abstract: A variable capacitor element including: a buried electrode layer of a conductivity type different from a semiconductor substrate; a wiring layer connected to the lead portion of the buried electrode layer; a pair of capacitive insulating films that are formed as regions having mutually opposing adjacent sides in a plane shape on a portion of the buried electrode layer excluding the lead portion; an insulator layer formed on the border region of each outside of the pair of capacitive insulating films in a direction perpendicular to the adjacent sides; a pair of conductor layers formed both on the respective capacitive insulating films and on the respective insulator layers; and wiring layers that are connected respectively to lead portions of the pair of conductor layers above the insulator layer. The capacitance value between the buried electrode layer and each of the conductor layers can be changed by changing the voltage between the buried electrode layer and the conductor layers.

Abstract: Micro-Electro-Mechanical System (MEMS) Variable Capacitor Apparatus and Related Methods. According to one embodiment, a MEMS variable capacitor is provided. The variable capacitor can include first and second electrodes being spaced apart, and at least one of the electrodes being movable when a voltage is applied across the first and second electrodes. The variable capacitor can also include a first conductive plate attached to and electrically isolated from the first electrode. Furthermore, the variable capacitor can include a second conductive plate attached to the second electrode and spaced from the first conductive plate for movement of at least one of the plates with respect to the other plate upon application of voltage across the first and second electrodes to change the capacitance between the first and second plates.

Abstract: The present invention is directed to a capacitor apparatus of the capacity variable type. This capacitor apparatus is manufactured by Micro Electro-Mechanical System technology, and comprises an insulating substrate (2) in which at least two capacitor electrodes (3), (4) are formed on one surface (2a) in the state where they are insulated each other, an actuator (5) formed by insulating material and having an external shape to bridge over the respective capacitor electrodes (3), (4), the actuator (5) being such that a conductor which respectively constitutes capacitors between the conductor (6) and these capacitor electrodes (3), (4), and drive means (7) for allowing this actuator (5) to undergo an operation to come into contact with one principal surface (2a) of the insulating substrate (2) or to become away therefrom.

Abstract: First and second varactors are disposed on a surface of a P-type substrate. The first varactor includes an N well disposed in the surface of the P-type substrate, a gate insulator disposed on the N well, and an N-type polysilicon layer disposed on the gate insulator. The second varactor includes an N well disposed in the surface of the P-type substrate, a gate insulator disposed on the N well, and a P-type polysilicon layer disposed on the gate insulator. The N-type polysilicon layer and P-type polysilicon layer are connected to a gate terminal. The N wells are connected to an SD terminal via P+ diffusion layers. The N-type polysilicon layer and P-type polysilicon layer have different work functions.

Abstract: A sensor for determining the presence of an analyte is disclosed comprising a reactive layer disposed between a base plate and a movable plate. The reactive layer is configured to interact with an analyte effecting a change in capacitance between the base plate and movable plate. When the analyte has a polarity or overall Hildebrand solubility parameter that is similar to the reactive layer, the change in capacitance is caused by a swelling of the reactive layer as analyte is absorbed into the reactive layer. This results in a decrease in capacitance. When the analyte has a solubility parameter not near the reactive layer, the absorbed analyte causes the reactive layer's total polarity to increase, an effect that dominates swelling. This causes an increase in capacitance. A capacitive sensing circuit is included for measuring the change in capacitance which is indicative of the analyte exposed to the sensor.

Abstract: A variable passive component is provided for fabrication on a microelectromechanical system (MEMS) device. A conductive portion is provided on a low-profile sliding dielectric sheet that cooperates with a conductive portion disposed on a substrate to provide a variable passive component. The passive component can be a variable inductor provided by moving a shorted spiral inductor formed on the dielectric sheet over a spiral inductor on the substrate with varying degrees of overlap causing varying inductance values. The passive component can be a variable capacitor that consists of a large conductive pad on a dielectric plate which slides over two adjacent pads on the substrate with varying overlap causing varying capacitance values.

Abstract: A tunable capacitor. The tunable capacitor has a first fixed capacitor electrode and a second fixed capacitor electrode opposite to one another. The tunable capacitor also has a movable element formed of a conductive material. The movable element is moveable between the first fixed capacitor electrode and the second fixed capacitor electrode to adjust the capacitance between the first fixed capacitor electrode and the second fixed capacitor electrode.

Abstract: A charge control circuit for controlling a micro-electromechanical device having a variable capacitance is disclosed. In one embodiment, a charge storage device is configured to store a charge amount. A switch circuit is configured to control the variable capacitance of the micro-electromechanical device by sharing the charge amount between the charge storage device and the micro-electromechanical device to equalize the charge storage device and the micro-electromechanical device to a same voltage.

Abstract: A variable capacitance element includes a coplanar line or signal conduction and a movable body, which are vertically displaced through a supporting bar and which are provided on a substrate. A movable electrode is provided between a first driving electrode and second and third driving electrodes which are movable electrodes. Voltage is applied between the movable electrodes, such that one of the movable electrodes is pressed against the coplanar line through a dielectric film. Thus, high frequency signals conducting through the coplanar line are shut off. When voltage is applied between the other electrodes, the movable electrode and the dielectric film are moved apart from the coplanar line. Thus, high frequency signals are conducted through the coplanar line.

Abstract: A variable capacitor. The variable capacitor has a movable capacitor electrode including a major surface and a fixed capacitor electrode including a major surface. The major surface of the fixed capacitor electrode is opposite the major surface of the movable capacitor electrode and is separated therefrom by a gap. The major surface of the movable capacitor electrode includes a rigidity-increasing feature. The rigidity-increasing feature further provides a capacitance-increasing topography and reduces snap-together of the capacitor electrodes.

Abstract: What are formed on an insulating substrate are gate electrodes and data electrodes provided in a grid pattern, a TFT provided in each grid and connected to the gate electrode and the data electrode, an interlayer insulating film formed on the TFT and including a contact hole penetrating the film itself, and a sense electrode provided on the interlayer insulating film and passing through the contact hole. On the interlayer insulating film, an upper layer insulating film is formed so as to cover the sense electrode. A surface of the interlayer insulating film in which surface the sense electrode is formed is flat. On this account, it is possible to provide an uneven pattern sensing device capable of smoothing out a surface thereof without any increase of the manufacturing process and limitation of a choice of materials for a protective film.

Abstract: A charge control circuit for controlling a micro-electromechanical system (MEMS) device having variable capacitor formed by first conductive plate and a second conductive plate separated by a variable gap distance. The charge control circuit comprises a switch circuit configured to receive a reference voltage having a selected voltage level and configured to respond to an enable signal having a duration at least as long as an electrical time constant constant of the MEMS device, but shorter than a mechanical time constant of the MEMS device, to apply the selected voltage level across the first and second plates for the duration to thereby cause a stored charge having a desired magnitude to accumulate on the variable capacitor, wherein the variable gap distance is a function of the magnitude of the stored charge.

Abstract: This invention relates to an apparatus and method of using a high frequency, high power, fluid dielectric variable capacitor for an impedance matching network. The apparatus consists of a bow-tie rotary vane, a set of two fixed vanes, and a set of rotating vanes adapted to rotate interdigitally between the fixed vanes. A dielectric fluid is circulated between the fixed vanes and the rotating vanes for cooling the device. This arrangement facilitates production of a device having a higher capacitance and a smaller size, thus making it suitable for use in a matching network.

Abstract: A charge control circuit for controlling a micro-electromechanical system (MEMS) device having variable capacitor formed by first conductive plate and a second conductive plate separated by a variable gap distance. The charge control circuit comprises a switch circuit configured to receive a reference voltage having a selected voltage level and configured to respond to an enable signal having a duration at least as long as an electrical time constant constant of the MEMS device, but shorter than a mechanical time constant of the MEMS device, to apply the selected voltage level across the first and second plates for the duration to thereby cause a stored charge having a desired magnitude to accumulate on the variable capacitor, wherein the variable gap distance is a function of the magnitude of the stored charge.

Abstract: A variable capacitor of the invention includes a beam having flexibility and an electrode provided close to the beam in order to form a capacitor with the beam. By applying a voltage to between the beam and the electrode to thereby deflect the beam by an electrostatic force, a capacitance between the both is changed. The deflected beam and the electrode are placed into contact through an insulation layer formed on a surface of at least one thereof, to change a contact area thereof, thereby changing the capacitance. Meanwhile, the electrode is divided in plurality. A recess is formed such that one electrode is lower than a height of another electrode surface. By applying a voltage to the beam and the electrode corresponding to the recess, the beam is pulled to an inside of the recess, thereby enabling to eliminate stiction.

Abstract: A tunable high-frequency capacitor includes first and second fixed electrodes, the first fixed electrode having a high-frequency input connection, and the second fixed electrode having a high-frequency output connection. A movable electrode is arranged facing and spaced apart from the fixed electrodes and is supported by means of a suspension which causes a displacement of the movable electrode in relation to the fixed electrode depending on a control signal that is applied.

Abstract: A trigger switch module suitable for use with various household appliances and instruments is capable of generating a signal needed by a microcontroller via a human-machine interface, so that the trigger switch module has stable signal level output pins for a microprocessor or a logic gate to make judgment easily. The trigger switch module can be triggered to output a signal through a non-direct contact of the switch at low voltage and low power consumption. All components of the trigger switch module are enclosed in a top casing that is completely watertight and dustproof to ensure stable capacity of the switch. The trigger switch module combines the functions of conventional switches but eliminates drawbacks thereof. A touch panel made of plastics, metal, glass, ceramic or other insulating material may be provided with the top casing to ensure safe and durable use of the trigger switch module.