A variable capacitance device includes: (A) a first signal line that contains multiple first variable capacitance elements connected in series; (B) a second signal line that contains multiple second variable capacitance elements connected in series; (C) a first bias line used for applying a first direct-current voltage to each of the multiple first variable capacitance elements and multiple second variable capacitance elements; and (D) a second bias line used for applying a second direct-current voltage to each of the multiple first variable capacitance elements and multiple second variable capacitance elements. And, a part of at least one of the first bias line and second bias line is arranged so that it passes between two adjacent first variable capacitance elements among the multiple first variable capacitance elements.

A method of manufacturing a variable capacitor includes forming a capacitor conductor. The method also includes forming a phase change material adjacent the capacitor conductor. The method further includes forming a first contact on the capacitor conductor. The method additionally includes forming a second contact and a third contact on the phase change material.

A method of manufacturing a variable capacitor includes forming a capacitor conductor. The method also includes forming a phase change material adjacent the capacitor conductor. The method further includes forming a first contact on the capacitor conductor. The method additionally includes forming a second contact and a third contact on the phase change material.

A method for preparing a supercapacitor with good cycling stability uses NiO@CoMoO.sub.4/NF, an activated carbon plate, a KOH solution (6 mol/L), and polypropylene as raw materials, and is implemented through preparation of an NiO@CoMoO.sub.4/NF electrode and assembly of the supercapacitor, wherein the NiO@CoMoO.sub.4/NF is the anode of the supercapacitor, the activated carbon plate is the cathode of the supercapacitor, the KOH solution is the electrolyte, and the polypropylene is an isolation plate. The NiO@CoMoO.sub.4/NF electrode in the supercapacitor of the present disclosure treated with the ductile material can better adapt to volume changes during the charging and discharging process. After 10,000 cycles of charging and discharging, the capacity of the present disclosure has not faded and still maintains 100% of the maximum capacity, with a high specific capacitance of 79.4 F/g, an energy density of 35.7 Wh/kg, and a functional density of 899.5 W/kg.

Phase change materials such as correlated oxides (e.g., such as NbO.sub.2, V.sub.2O.sub.3 and VO.sub.2) enable wide tuning of dielectric properties via control of temperature, electric fields, optical fields or disorder. The distinct dielectric states can be volatile or non-volatile depending on how the phase is created. Possible fabrication techniques for oxide and insulating matrix composites may include sequential/co-deposition routes as well as local controlled disorder. By combining the distinct insulating and metallic states in these systems and by control of the ground state via induced defects, artificial electronic composites, whose properties can be tuned, could be manufactured. The composites can be integral components of coplanar waveguide devices and microwave switches. More broadly, tunable electronic composites using oxide systems that undergo insulator-metal transitions may have wide usage in frequency tunable devices, including microwave devices.

Phase change materials such as correlated oxides (e.g., such as NbO.sub.2, V.sub.2O.sub.3 and VO.sub.2) enable wide tuning of dielectric properties via control of temperature, electric fields, optical fields or disorder. The distinct dielectric states can be volatile or non-volatile depending on how the phase is created. Possible fabrication techniques for oxide and insulating matrix composites may include sequential/co-deposition routes as well as local controlled disorder. By combining the distinct insulating and metallic states in these systems and by control of the ground state via induced defects, artificial electronic composites, whose properties can be tuned, could be manufactured. The composites can be integral components of coplanar waveguide devices and microwave switches. More broadly, tunable electronic composites using oxide systems that undergo insulator-metal transitions may have wide usage in frequency tunable devices, including microwave devices.

A structural capacitor having a plurality of planar dielectric layers and a plurality of positive and negative electrodes with the positive and negative electrodes alternating between each dielectric layer and methods for making structural capacitors are provided. First and second spaced apart holes are provided through each dielectric layer as well as the electrodes so that the first holes in the electrodes register with the first holes in the dielectric layer and likewise for the second holes. The capacitor is formed by stacking the dielectric layers and electrodes on two spaced apart alignment pins with a positive alignment pin extending through the first holes and a negative alignment pin extending through the second holes in the dielectric layers and electrodes. These alignment pins maintain layer alignment during subsequent thermal and pressure processing to bond together the dielectric and electrode layers into an integral structural material. After processing, the alignment pins are removed and replaced with electrode pins, where the positive electrode pin is in electrical contact only with the positive electrodes and the negative electrode pin is in electrical contact only with the negative electrodes. The electrode pins are used for subsequent electrical and mechanical connectorization to the structural capacitor.

Capacitors, apparatus including a capacitor, and methods for forming a capacitor are provided. One such capacitor may include a first conductor a second conductor above the first conductor, and a dielectric between the first conductor and the second conductor. The dielectric does not cover a portion of the first conductor; and the second conductor does not cover the portion of the first conductor not covered by the dielectric.

Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.

Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.