Superconductor Technologies Inc.

George L Matthaei

Balam A Willemsen

Richard C Eden

Gregory Lynton Hey-Shipton

Genichi Tsuzuki

Roger J Forse

Eric M Prophet

Stephan M Rohlfing

A narrowband filter comprises an input terminal, an output terminal, and an array of basic resonator structures coupled between the terminals to form a single resonator having a resonant frequency. The resonator array may be arranged in a plurality of columns of basic resonator structures, with each column of basic resonator structures having at least two basic resonator structures. The basic resonator structures in each column may be coupled between the terminals in parallel or in cascade. Two or more resonator arrays may be coupled to generate multi-resonator filter functions.

Zig-zag array resonators for relatively high-power HTS applications

A tunable filter having a fixed substrate, a first and second plate comprising a high-temperature superconductor material on the fixed substrate, a movable substrate, a mechanical driver attached to the fixed substrate and the movable substrate, a floating plate comprising a high-temperature superconductor material on the fixed substrate wherein the floating plate, the first plate, and the second plate define a gap, and wherein the gap is varied by length changes in the mechanical driver is provided.

High temperature superconducting tunable filter with an adjustable capacitance gap

High temperature superconductor tunable filter

Microwave hairpin-comb filters utilize a plurality of hairpin (i.e., folded) half-wavelength microstrip or stripline resonators arranged side-by-side and all with the same orientation. The coupling regions between resonators extend parallel to the sides of the resonators for substantially 1/8 to 1/4 wavelength at the frequency of resonance of the resonators. This length of coupling region between resonators, along with all resonators being oriented in the same direction, result in resonance effects in the coupling regions between the resonators. These effects greatly reduce the couplings between the resonators so that the resonators can be very closely spaced so as to produce a compact filter structure yet still have a narrow passband. The structure can also be made to produce poles of attenuation adjacent to the passband in order to enhance the filter cutoff characteristic. The filter structure can be conveniently tuned using asymmetric dielectric pieces which rotate above an interdigital conductor pattern placed between the open ends of each resonator, the axis of rotation being normal to the substrate. This manner of tuning is particularly attractive for narrow-band, very low loss, high temperature superconductor (HTS) filters since these tuners can be made to give smooth tuning with no normal metal parts in the circuit and with no ground connections required. Such normal metal parts or ground connections would introduce considerable loss and degrade the HTS filter performance.

Microwave hairpin-comb filters for narrow-band applications

Microwave hairpin-comb filters utilize a plurality of hairpin (i.e., folded) half-wavelength microstrip or stripline resonators arranged side-by-side and all with the same orientation. The coupling regions between resonators extend parallel to the sides of the resonators for substantially 1/8 to 1/4 wavelength at the frequency of resonance of the resonators. This length of coupling region between resonators, along with all resonators being oriented in the same direction, result in resonance effects in the coupling regions between the resonators. These effects greatly reduce the couplings between the resonators so that the resonators can be very closely spaced so as to produce a compact filter structure yet still have a narrow passband. For example, a compact narrow band filter structure is possible using high-Q nominally half wavelength hairpin resonators. The structure can also be made to produce poles of attenuation adjacent to the passband in order to enhance the filter cutoff characteristic. The filter structure can be conveniently tuned using asymmetric dielectric pieces which rotate above an interdigital conductor or other two conductors pattern placed between the open ends of each resonator, the axis of rotation being normal to the substrate. This manner of tuning is particularly attractive for narrow-band, very low loss, high temperature superconductor (HTS) filters since these tuners can be made to give smooth tuning with no normal metal parts in the circuit and with no ground connections required. Such normal metal parts or ground connections would introduce considerable loss and degrade the HTS filter performance.

Tunable microwave hairpin-comb superconductive filters for narrow-band

Lumped element electrical components, such as inductors and capacitors, are formed to include high temperature superconducting materials. In the preferred embodiment, thin film epitaxial high temperature superconductors are patterned to form capacitors and inductors on low loss substrates. Preferably, a ground plane is formed on the back side of the substrate, most preferably being formed of high temperature superconducting material, or other highly conductive materials such as gold or copper. Various advantageous structures include a planar spiral structure, a zig-zag serpentine structure, a single coil structure and a double coil structure. Single layer and multilayer structures are included. Improved narrow bandpass filters, bandreject filters and high Q resonator structures are formed. Chebyshev bandpass filters are formed from multiple series connected zig-zag filter structures. Chebyshev, elliptic and quasi-elliptic bandreject filters are formed from a plurality of bandreject structures, each of which includes a zig-zag or serpentine inductor. A quasi-elliptic bandpass filter utilizes a plurality of series connected bandpass structures with planar cross-coupling of bandpass structures.

High temperature superconductor lumped element band-reject filters

A bandpass filter comprises multiple side-coupled strip line resonators wherein the resonators are staggered or offset with respect to their nearest neighbors by substantially 1/4 wavelength or less. In the preferred embodiment, the strip line bandpass filter structure has substantially parallel resonators arrayed with substantially constant spacing between the resonators with 1/4 wavelength overlap or less. Generally, the amount of stagger between nearest neighbors is reduced for resonators toward the center of the filter. Coupling between resonators is controlled by varying the relative amount of stagger between resonators. The resonators may be formed from normal metal or superconducting materials, such as YBCO or thallium containing superconductors. A strip line structure may be formed by utilizing two mirror structures each comprising a substrate having a ground plane and a patterned staggered resonator array formed on the substrate on a side opposite the ground plane. In another aspect of this invention, a ground plane tuning system utilizes a variable positioning member. The member is moveable towards and away from the resonator array, resulting in tuning. In the preferred embodiment, a threaded plug mates with a threaded housing opening, permitting tuning by rotation of the insert.

Growing community of inventors

Santa Barbara, CA, United States of America

George L Matthaei