Superconductor technology: apparatus – material – process – High temperature devices – systems – apparatus – com- ponents,... – High frequency waveguides – resonators – electrical networks,...
Reexamination Certificate
2000-07-26
2002-12-17
Lee, Benny T. (Department: 2817)
Superconductor technology: apparatus, material, process
High temperature devices, systems, apparatus, com- ponents,...
High frequency waveguides, resonators, electrical networks,...
C333S09900R, C333S204000
Reexamination Certificate
active
06496710
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application relates to and incorporates herein by reference Japanese Patent Application No. 2000-122857 filed on Apr. 24, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a filter in which a plurality of resonators are formed circularly around the center of a substrate.
2. Related Art
In some conventional filters, resonators are formed in a hairpin pattern or forward-coupled pattern. The hairpin type is disclosed in, for instance, IEICE Transactions on Electronics, Vol. E82-C No. Jul. 7, 1999, “High-temperature Superconducting Receiving Filtering Subsystem for Mobile Telecommunication Base Station” of Appl. Phys. Lett. 71(26), Dec. 29, 1997, “Microwave intermodulation in thin film high-Tc superconducting microstrip hairpin resonators : Experiment and theory.” The forward-coupled type is disclosed in, for instance, Appl. Phys. Lett. 69(4), Jul. 22, 1996, “High power failure of superconducting microwave filters: Investigation by means of thermal imaging.”
The filters formed with the above resonator patterns require large substrates which extend in a lateral direction, when formed in multiple stages, or have only a limited number of stages in a fixed area. Further, it is difficult to regulate the coefficient or ratio of cross coupling which occurs between resonators other than the adjacent resonators in the above resonator patterns.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a filter in which a plurality of resonators can be formed in a limited area of a substrate.
It is another object of the present invention to provide a filter in which the coefficient of coupling between resonators can be regulated with ease.
It is a further object of the present invention to provide a filter in which notches are provided at both edges of a passband for a sharp filtering or cut-off response.
According to the present invention, a filter for filtering electrical signals comprises a substrate and a plurality of resonators formed circularly on the substrate to surround the center of the substrate.
Each resonator has an arcuate part at a radially outermost part and a pair of linear parts extending from ends of the arcuate part in a radially inward direction and the arcuate part is located at the same distance from the center of the substrate. Thus, the number of the resonators provided in a limited area may be increased. Further, the linear parts of each resonator have different lengths from each other thereby to provide a sharp decrease of gain at edges of the passband in a filtering response.
REFERENCES:
patent: 6130189 (2000-10-01), Matthaei
patent: 6130591 (2000-10-01), Tsuzuki
Yoshiki Ueno et al., “High-temperature Superconducting Receiving Filter Subsystem for Mobile Telecommunication Base Station”, IEICE Transactions on Electronics, vol. E82-C No. 7, Jul. 1999, pp. 1172-1176.
Balam Willemsen et al., “Microwave intermodulation in thin film high-Tc superconducting microstrip haripin resonators: Experiment and Theory.” Appl. Phys. Lett. 71 (26) Dec. 1997, pp. 3898-3900.
G. Hampel et al., “High power failure of superconducting microwave filters: Investigation by means of thermal imaging” Appl. Phys. Lett. 69 (4), Jul. 1996, pp. 571-573.
George L. Matthaei et al., Novel Staggered Resonator Array Superconducting 2.3-GHz Bandpass Filter, IEEE Transactions On Microwave Theory and Techniques, vol. 41., No. 12., Dec. 1993, pp. 2345-2352.
Cryodevice Inc.
Law Offices of David G. Posz
Lee Benny T.
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