A low RF frequency electro-mechanical load pull impedance tuner uses four rotary, remotely controlled variable shunt capacitors and four fixed series transmission lines to create up to 10.sup.8 independently controllable impedance states at each frequency covering the entire Smith chart in the frequency range between below 1 and 5 MHz; the capacitors and control motors and gear are immersed in a mixture of dielectric fluids inside individual sealed containers including also adequate liquid stirring mechanisms. Appropriate, Error Function based optimization algorithms, allow fast impedance tuning at the fundamental frequency at the output of DUT's operated in high gain compression. Stepper motors, drivers and control software are used to remotely control the variable shunt capacitors of the tuner and allow it to be automated, pre-calibrated and used in an automated load pull measuring setup.

An MEMS structure-based adjustable capacitor is provided, comprising: a lower plate A, a movable plate B, an upper plate C, a fixed apparatus D and one or more connecting conductors E; a lower end of the fixed apparatus D is fixedly connected to the lower plate A, an upper end of the fixed apparatus D is fixedly connected to the upper plate C, a structure B4 is provided at a middle part of movable plate B, and the movable plate B is able to move up and down along the fixed apparatus D; the lower plate A is provided with a lower electrode A1, and the movable plate B is provided with a movable electrode B1 and adjustment electrodes B2; the lower electrode A1 and the movable electrode B1 constitute a unit capacitor; and the upper plate C is provided with an upper electrode C1 and adjustment electrodes C2.

An MEMS structure-based adjustable capacitor is provided, comprising: a lower plate A, a movable plate B, an upper plate C, a fixed apparatus D and one or more connecting conductors E; a lower end of the fixed apparatus D is fixedly connected to the lower plate A, an upper end of the fixed apparatus D is fixedly connected to the upper plate C, a structure B4 is provided at a middle part of movable plate B, and the movable plate B is able to move up and down along the fixed apparatus D; the lower plate A is provided with a lower electrode A1, and the movable plate B is provided with a movable electrode B1 and adjustment electrodes B2; the lower electrode A1 and the movable electrode B1 constitute a unit capacitor; and the upper plate C is provided with an upper electrode C1 and adjustment electrodes C2.

A variable capacitor device and a method of preparation thereof, wherein the variable capacitor device comprises a shape-memory polymer in its dielectric layer, wherein the shape-memory polymer determines the thickness of the dielectric layer, thereby causing the capacitance of the variable capacitor device to be tuned. Various embodiments of the variable capacitor device and the method of preparing said capacitor have also been provided.

A sound or thermal baffling device comprising an enclosure containing a variable density fluid and a force generating means for preserving and creating the structure and form of the enclosure, the shape and composition of the enclosure crafted to vary the baffling characteristics of the enclosure, and a further embodiment showing how a cellular material containing a variable density fluid may be created and used, and a still further embodiment showing improvements to ear protectors and head phone sets, including latching means for attaching these and other devices to the ears and head. Various applications involving previous as well as new uses are set out, including a description of how dynamic sound baffling may be implemented.

An anode body for a solid electrolytic capacitor element, which is an anode body for a solid electrolytic capacitor element having a dielectric layer on the surface of a sintered body, wherein at least a part of the surface of the valve-acting metal particles constituting the sintered body is covered with a dielectric layer, and a part of the dielectric layer on the particle surface has a larger thickness than the other part; and a method for producing the same, in which a sintered body of a valve-acting metal is immersed in an aqueous solution of an oxidizing agent after being subjected to chemical formation, the resulting sintered body is then immersed in water-soluble alcohol and dried, and the oxidizing agent is removed by water washing.

A vacuum variable capacitor includes a vacuum sealed enclosure to contain a vacuum dielectric medium, wherein the enclosure includes a first plate and a second plate, the first plate and the second plate being separated by an electrically insulating element, a fixed electrode attached inside the enclosure to the first plate and a movable electrode attached to a movable plate, wherein the movable plate is attached inside the enclosure to the second plate by at least one vacuum bellows, wherein the vacuum capacitor includes a mechanical drive system for displacing, in particular translating, the movable plate relative to the first plate so as to vary the capacitance of the vacuum capacitor, wherein the mechanical drive system includes a ball screw arranged to drive the movable plate and wherein the mechanical drive system includes outside of the vacuum sealed enclosure a limiting element limiting the maximum distance between the first plate and the movable plate and wherein the drive system includes a nut attached to the ball screw, wherein the nut includes a first shoulder configured to abut against the limiting element to limit the maximum distance between the first plate and the movable plate.

A vacuum variable capacitor includes a vacuum sealed enclosure to contain a vacuum dielectric medium, wherein the enclosure includes a first plate and a second plate, the first plate and the second plate being separated by an electrically insulating element, a fixed electrode attached inside the enclosure to the first plate and a movable electrode attached to a movable plate, wherein the movable plate is attached inside the enclosure to the second plate by at least one vacuum bellows, wherein the vacuum capacitor includes a mechanical drive system for displacing, in particular translating, the movable plate relative to the first plate so as to vary the capacitance of the vacuum capacitor, wherein the mechanical drive system includes a ball screw arranged to drive the movable plate and wherein the mechanical drive system includes outside of the vacuum sealed enclosure a limiting element limiting the maximum distance between the first plate and the movable plate and wherein the drive system includes a nut attached to the ball screw, wherein the nut includes a first shoulder configured to abut against the limiting element to limit the maximum distance between the first plate and the movable plate.

A vacuum variable capacitor includes a pre-vacuum enclosure for reducing a pressure differential across the bellows. The vacuum force load on the drive system can thereby be reduced, allowing faster movement of the movable electrode, faster capacitance adjustment of the vacuum variable capacitor and longer lifetimes of the device.

A vacuum variable capacitor includes a pre-vacuum enclosure for reducing a pressure differential across the bellows. The vacuum force load on the drive system can thereby be reduced, allowing faster movement of the movable electrode, faster capacitance adjustment of the vacuum variable capacitor and longer lifetimes of the device.