An electrical filter circuit is disclosed. The circuit includes a first input line and a second input line. A first transmission line is coupled electrically in series at a first node with a first output line, and an inductor is coupled electrically in series between the first input line and the first transmission line. The filter also includes a second transmission line having a first impedance coupled to the first node. The second input line is coupled electrically in series at a second node with a second output line. A third transmission line is coupled to the second node, and a capacitor is coupled electrically in series between the second transmission line and the third transmission line. The first output line has a second impedance that is greater than the first impedance.

An electrical filter circuit is disclosed. The circuit includes a first input line and a second input line. A first transmission line is coupled electrically in series at a first node with a first output line, and an inductor is coupled electrically in series between the first input line and the first transmission line. The filter also includes a second transmission line having a first impedance coupled to the first node. The second input line is coupled electrically in series at a second node with a second output line. A third transmission line is coupled to the second node, and a capacitor is coupled electrically in series between the second transmission line and the third transmission line. The first output line has a second impedance that is greater than the first impedance.

In many cases after degaussing the field distribution in a magnetic material there may be regions within the magnetic material that have ordered domains that contribute a remnant field. There is the need to reduce or eliminate non-uniform fields within a volume of interest left after degaussing a magnetic shield. Degaussing coils surrounding a metal shield can be used to favorably order magnetic domains within the material to counteract the remnant fields left behind following imperfect degaussing. The remnant field value can be measured and a small current may be applied through the degaussing coils. After removing the current, the field can be measured again and a higher current may be applied again through the coils. Repeated applications of currents and field measurement will progressively order domains in the direction of the applied field, resulting in a reduction of the net field and lower field gradient across the volume of interest.

In many cases after degaussing the field distribution in a magnetic material there may be regions within the magnetic material that have ordered domains that contribute a remnant field. There is the need to reduce or eliminate non-uniform fields within a volume of interest left after degaussing a magnetic shield. Degaussing coils surrounding a metal shield can be used to favorably order magnetic domains within the material to counteract the remnant fields left behind following imperfect degaussing. The remnant field value can be measured and a small current may be applied through the degaussing coils. After removing the current, the field can be measured again and a higher current may be applied again through the coils. Repeated applications of currents and field measurement will progressively order domains in the direction of the applied field, resulting in a reduction of the net field and lower field gradient across the volume of interest.

A coupling loop circuit is constructed in such a way that a sixth conductor is made to three-dimensionally cross a second conductor, an eighth conductor is made to three-dimensionally cross each of the second conductor and a fourth conductor, a first loop area and a second loop area spatially overlap each other, and an overlapping area between the first loop area and the second loop area is formed by the second conductor, the fourth conductor, the sixth conductor, and the eighth conductor.

A coupling loop circuit is constructed in such a way that a sixth conductor is made to three-dimensionally cross a second conductor, an eighth conductor is made to three-dimensionally cross each of the second conductor and a fourth conductor, a first loop area and a second loop area spatially overlap each other, and an overlapping area between the first loop area and the second loop area is formed by the second conductor, the fourth conductor, the sixth conductor, and the eighth conductor.

Fabrication of superconducting devices that combine or separate direct currents and microwave signals is provided. A method can comprise forming a direct current circuit that supports a direct current, a microwave circuit that supports a microwave signal, and a common circuit that supports the direct current and the microwave signal. The method can also comprise operatively coupling a first end of the direct current circuit and a first end of the microwave circuit to a first end of the common circuit. The direct current circuit can comprise a bandstop circuit and the microwave circuit can comprise a capacitor. Alternatively, the direct current circuit can comprise a bandstop circuit and the microwave circuit can comprise a bandpass circuit. Alternatively, the microwave circuit can comprise a capacitor and the direct current circuit can comprise one or more quarter-wavelength transmission lines.

Fabrication of superconducting devices that combine or separate direct currents and microwave signals is provided. A method can comprise forming a direct current circuit that supports a direct current, a microwave circuit that supports a microwave signal, and a common circuit that supports the direct current and the microwave signal. The method can also comprise operatively coupling a first end of the direct current circuit and a first end of the microwave circuit to a first end of the common circuit. The direct current circuit can comprise a bandstop circuit and the microwave circuit can comprise a capacitor. Alternatively, the direct current circuit can comprise a bandstop circuit and the microwave circuit can comprise a bandpass circuit. Alternatively, the microwave circuit can comprise a capacitor and the direct current circuit can comprise one or more quarter-wavelength transmission lines.

A balun and a method for manufacturing the same are disclosed. According to an embodiment, the balun comprises a substrate, and a first and a second coplanar waveguide (CPW) couplers which are disposed on the substrate and cascaded with each other. Each CPW coupler comprises two first ground planes disposed on a first side of the substrate, a first microstrip line and at least two second microstrip lines which are disposed on the first side of the substrate between the two first ground planes, and at least one third microstrip line that is disposed on an opposite side of the substrate. The first microstrip line and the at least two second microstrip lines can be coupled with each other by electromagnetic coupling. The at least one third microstrip line electrically connects the at least two second microstrip lines with each other by via-holes.

A balun and a method for manufacturing the same are disclosed. According to an embodiment, the balun comprises a substrate, and a first and a second coplanar waveguide (CPW) couplers which are disposed on the substrate and cascaded with each other. Each CPW coupler comprises two first ground planes disposed on a first side of the substrate, a first microstrip line and at least two second microstrip lines which are disposed on the first side of the substrate between the two first ground planes, and at least one third microstrip line that is disposed on an opposite side of the substrate. The first microstrip line and the at least two second microstrip lines can be coupled with each other by electromagnetic coupling. The at least one third microstrip line electrically connects the at least two second microstrip lines with each other by via-holes.