Illinois Superconductor Corporation, Inc.

James D Hodge

Lori J Klemptner

Stephen K Remillard

Justin Whitney

David S Applegate

Donald E Richied

Qiang Huang

Peter M Winandy

Nikolay Ortenberg

Edward A Freeman

An electromagnetic resonator has a resonant element made of a high-temperature superconducting material such as YBa,Cu,O,. The resonant element has a substrate coated with a thermally conductive layer such as silver, over which the high-temperature superconductor material is placed. The thermally conductive layer distributes heat along the length of the resonant element to minimize the effects of localized heating at, for instance, the center of the resonator. The resonant element is held to a housing by a mounting mechanism including a post made of polycrystalline alumina. The polycrystalline alumina transfers heat away from the center of the resonant element and may be used to suppress spurious response due to second harmonic resonance.

Electromagnetic resonator

A stripline resonator has a center conductor between layers of dielectric which are, in turn, between ground planes. The center conductor is made of a high-temperature superconducting material, preferably having a total superconductor thickness from at least about one micron to at least about one-hundred microns. The superconducting material has an electromagnetic penetration depth and the ratio of the thickness of the superconductor to the penetration depth is from at least about 4:1 to at least about 100:1. The center conductor may be formed of a substrate coated with the high-temperature superconducting material so that the center conductor is discrete from the dielectric element. The center conductor may have a length which is greater than the length of the dielectric element.

Stripline resonator using high-temperature superconductor components

An electromagnetic device, such as a resonator for a filter, incorporates a high-purity polycrystalline alumina. The device may include a superconducting component, which must be cooled significantly below room temperature. The high-purity polycrystalline alumina may be a dielectric slab in a stripline resonator, or may be used as a stand for holding other components. The high-purity polycrystalline alumina exhibits a very low loss tangent at cryogenic temperatures, and therefore will result in an electromagnetic device with superior performance characteristics.

High-purity polycrystalline alumina cryogenic dielectric

A magnetically-activated switch including a high temperature superconductor. The magnetic switch includes a high temperature superconductor coupled at both ends to a rigid beam, a thermal shield structure is disposed adjacent to the superconductor and a magnetic field source is positioned near the superconductor to allow transitioning of the superconductor in and out of the superconducting state.

Magnetically activated switch using a high temperature superconductor

A high temperature superconductor fault current limiter and a method of using same. The fault current limiter comprises a high temperature superconductor material structure at least partially encapsulated in an epoxy having thermal conductivity properties that enable the superconductor to heat rapidly during a fault condition while preventing thermal runaway. The epoxy encapsulation decreases the critical current density of the superconductor material structure and increases the rate at which resistance increases with increasing current once the critical current density is exceeded. Preferably, the epoxy has thermal expansion properties approximately equal to the thermal expansion properties of the superconductor material structure.

High temperature superconductor element for a fault current limiter

A method of measuring a cryogenic fluid level utilizing a high temperature ceramic superconductor material driven above its level of critical current density. A high temperature ceramic superconductor is placed in cryogenic fluid and a voltage is applied between two points on the superconductor. The voltage drop is then measured at a third point on the superconductor. This voltage drop corresponds to the change in cryogenic fluid level, and thus can be used to measure the fluid level. Sensitivity of the measurement is increased by driving the high temperature ceramic superconductor above its level of critical current density.

Cryogenic fluid-level sensor

A high temperature superconductor and composite structure. A superconductor is disposed on a silver substrate without interdiffusion. The superconductor is formed by heating to a temperature not exceeding the peritectic point of the superconductor material, providing an oxidizing atmosphere while not exceeding the melting point of silver and disposing the superconductor on the silver substrate.

Superconducting YBa.sub.2 Cu.sub.3 O.sub.7-x produced at low temperatures

A fault current limiter incorporating a high temperature superconductor material. During a fault condition, the superconductor material is allowed to operate above its critical temperature, providing sharply increased resistance. The fault current limiter can be sized and selectively cooled to provide a desired range of fault current limiting capability.

Self-restoring fault current limiter utilizing high temperature

A cryogenic fluid level sensor utilizing a high temperature ceramic superconductor material driven above its level of critical current density, an exterior housing for holding the length of ceramic superconductor material, a support material disposed between the ceramic superconductor material and the exterior housing, and a resilient retention material disposed opposite the ceramic superconductor material for holding the superconductor material while allowing expansion and contraction thereof during thermal cycling. A method of producing a superconductor material having a low level of critical current density and favorable structural properties is also disclosed.

Cryogenic fluid level sensor

A method of preparing a superconductor. The method includes preparing a mixture of superconductor material constituents, disposing the constituents on a silver containing substrate, heating the mixture of constituents on a silver containing substrate, heating the mixture in a first atmosphere having a partial pressure of CO.sub.2 to control decomposition of at least one of the superconductor material constituents and changing the first atmosphere to a second atmosphere consisting essentially of an oxidizing gas capable of allowing decomposition of at least one of the superconductor material constituents.

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Lincolnwood, IL, United States of America

James D Hodge