An active metamaterial array of the present disclosure includes: a substrate; a plurality of metamaterial structures disposed on the substrate and spaced apart from each other; a conductivity variable material layer formed between each of the plurality of the metamaterial structures so as to selectively connect the metamaterial structures; an electrolyte material layer formed on the metamaterial structures and the conductivity variable material layer; and a gate electrode disposed at one end of the substrate so as to be in contact with one region of the electrolyte material layer, and when an external voltage is applied to the gate electrode, the gate electrode changes the conductivity of the conductivity variable material layer by controlling the migration of ions contained in the electrolyte material layer.

A capacitor provides a plurality of selectable capacitance values, by selective connection of six capacitor sections of a capacitive element each having a capacitance value. The capacitor sections are provided in a plurality of wound cylindrical capacitive elements. Two vertically stacked wound cylindrical capacitance elements may each provide three capacitor sections. There may be six separately wound cylindrical capacitive elements each providing a capacitor section. The capacitor sections have a common element terminal.

A capacitor provides a plurality of selectable capacitance values, by selective connection of six capacitor sections of a capacitive element each having a capacitance value. The capacitor sections are provided in a plurality of wound cylindrical capacitive elements. Two vertically stacked wound cylindrical capacitance elements may each provide three capacitor sections. There may be six separately wound cylindrical capacitive elements each providing a capacitor section. The capacitor sections have a common element terminal.

A capacitor provides a plurality of selectable capacitance values, by selective connection of six capacitor sections of a capacitive element each having a capacitance value. The capacitor sections are provided in a plurality of wound cylindrical capacitive elements. Two vertically stacked wound cylindrical capacitance elements may each provide three capacitor sections. There may be six separately wound cylindrical capacitive elements each providing a capacitor section. The capacitor sections have a common element terminal.

A capacitor provides a plurality of selectable capacitance values, by selective connection of six capacitor sections of a capacitive element each having a capacitance value. The capacitor sections are provided in a plurality of wound cylindrical capacitive elements. Two vertically stacked wound cylindrical capacitance elements may each provide three capacitor sections. There may be six separately wound cylindrical capacitive elements each providing a capacitor section. The capacitor sections have a common element terminal.

Devices, systems, and methods for limiting a slew rate of a driven device. In some embodiments, the device for limiting a slew rate of the driven device includes one or more slew rate limiting field-effect transistors (FETS) connected between a first circuit node and a node of the driven device, and a first control circuit. In some embodiments, the one or more first slew rate limiting FETs and the first control circuit are configured to set a rate at which the driven device is charged or discharged. In some embodiments, the first control circuit is within a voltage divider and the current flowing through the voltage divider is proportionally mirrored to the one or more first slew rate limiting FETs wherein the current mirror ratio is selected to ensure that a rate at which a capacitance of the driven device changes over time is below a specified limit.

Devices, systems, and methods for limiting a slew rate of a driven device. In some embodiments, the device for limiting a slew rate of the driven device includes one or more slew rate limiting field-effect transistors (FETS) connected between a first circuit node and a node of the driven device, and a first control circuit. In some embodiments, the one or more first slew rate limiting FETs and the first control circuit are configured to set a rate at which the driven device is charged or discharged. In some embodiments, the first control circuit is within a voltage divider and the current flowing through the voltage divider is proportionally mirrored to the one or more first slew rate limiting FETs wherein the current mirror ratio is selected to ensure that a rate at which a capacitance of the driven device changes over time is below a specified limit.

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.

Energy storage devices are disclosed that store both electrical and mechanical energies, making the total energy stored larger than either an electrical or mechanical means alone. The energy storage device is charged by the application of a voltage, which charges a capacitor to store electrical energy while simultaneously exerting a force on the mechanical system that deforms the mechanical system, resulting in mechanical energy storage. When the charged device is discharged, both the electrical and mechanical energy are extracted in electrical form. Its unique features include, but are not limited to, the potential for long lifetime, improved safety, better portability, a wide operating temperature range, and environment friendliness. Arrays of energy storage devices can be assembled in various configurations to build high capacity energy storage units.