Abstract: A filter is composed of plural resonators formed on one surface of a dielectric substrate and a ground plane formed on the other surface. A resonant frequency of each resonator is accurately measured individually and independently from other resonators. Other resonators not selected for measurement are all short-circuited or covered with a conductive member to shift their resonant frequency to a region that does not interfere with the resonant frequency of the resonator under measurement. Also, a coupling coefficient of an arbitrary pair of resonators is accurately measured under no interference from other resonators in the similar manner.

Abstract: A mounting structure for a high temperature superconductor device, such as a filter, housed in a closed vacuum chamber and operated at a low temperature. The filter has dielectric substrate having: first and second surfaces; a circuit portion made of a superconducting thin film formed on the first surface of the dielectric substrate; and a ground layer consisting of a superconducting thin film formed on second surface of the dielectric substrate and a metal film deposited on the superconducting thin film. The mounting structure comprises: a device holder for holding the filter thereon; a conductive layer intervening between the ground layer of the filter and the device holder; urging parts for resiliently urging the filter toward the device holder. The conductive layer is made of a metal selected from among the group consisting of gold, silver, copper, aluminum and an alloy made of at least one of gold, silver, copper, and aluminum.

Abstract: Plural resonators formed on a dielectric substrate constitute a filter. The resonant frequency of each resonator is adjusted to a target frequency by accumulating dielectric material on the resonator. The degree of such adjustment is substantially proportional to the amount of the dielectric material. The resonators are originally designed to have a resonant frequency that is a little higher than the target frequency. The resonant frequency of each resonator deviates from the designed target because of various factors in manufacturing processes. Each resonant frequency is measured, its deviation from the target is calculated, and the amount of the dielectric material required to eliminate such deviation is determined before the adjustment process. Accordingly, the adjustment is easily performed without measuring the resonant frequency during the adjustment process.

Abstract: The linear compressor for compressing and expanding working fluid contained in a regenerative refrigerator is composed of a compressor casing in which a pair of pistons are disposed and a plurality of electromagnets for driving the pair of pistons. A pair of rods for driving the pair of pistons are also disposed in the compressor casing, and permanent magnets are mounted on the driving rods. The plurality of electromagnets are disposed outside of the compressor casing along the axis of the driving rods so that the electromagnets face the permanent magnets. The pair of driving rods are driven by magnetic force between the permanent magnets and the electromagnets which are excited by alternating current. The linear compressor can be made small in size and heat generated in the electromagnets can be easily dissipated, because the electromagnets are disposed outside of the compressor casing.

Abstract: A heat exchanger comprises a gas casing formed with a gas chamber filled with a refrigerant gas, and a heat exchanging unit received in the gas chamber of the gas casing. The heat exchanging unit has a plurality of regenerative plates each made of a material having a thermal conductivity and a heat capacity. The regenerative plates are positioned in face-to-face and thermally insulated relationships to one another with the surfaces being in substantially perpendicular to the center axis of the heat exchanging unit to define spaces each between the neighboring two regenerative plates. Each of the regenerative plates may be shaped in the symmetrical outline form with respect to its central point and smaller in size than the cross-sections of the gas chamber of the gas casing. Each of the regenerative plates has a plurality of airy holes formed therein.

Abstract: Herein disclosed is a band-pass filter for a radio wave having a wavelength range of a high frequency, such as a microwave and a milliwave. The band-pass filter comprises: a dielectric substrate; input and output terminals; and a plurality of conductive strip line resonators being capable of resonating with a predetermined wavelength. Each of the strip line resonators has two ends and bent line extending from one end to the other end with a predetermined length corresponding to the wavelength. The one end and the other end are placed face to face with each other to provide a gap therebetween. In the band-pass filter, the plurality as arranged on the dielectric substrate in series and spaced apart from each other at predetermined intervals along a predetermined position line and coupled with each other through the inductive and capacitive coupling to transfer the signal between the resonators one after another.

Abstract: Plural units each composed of a metallic frame and a dielectric substrate mounted on the frame are stacked on one another, thereby forming a unitary case. A superconducting circuit such as a resonator is formed on an upper surface of the substrate, and a ground plane, made of a metallic material, preferably, a superconducting material, is formed on a lower surface of the substrate. The ground plane is exposed to a center opening of the frame, so that the ground plane of one substrate faces the superconducting circuit of another substrate which is stacked underneath the one substrate with a space therebetween. Thus, a plurality of the superconducting circuits are mounted in a compact unitary case.

Abstract: A coaxial connector is provided for a coaxial cable having an inner conductor, a dielectric member and an outer conductor which is made of a metal thin film. The coaxial connector comprises a connector pin electrically connected to the inner conductor, a cylindrical connector body formed with a through bore having part of said connector member and one end portion of the coaxial cable received therein, a cylindrical housing rotatably mounted around and in concentric and radially spaced relation with the cylindrical connector body so as to have the cylindrical connector body and the coaxial cable held at a standstill to each other, a tubular conductor having a cylindrical wall portion having a thickness larger than that of the outer conductor of the coaxial cable. The tubular conductor is interposed between the inner surface of the body and the outer surface of the coaxial cable in concentric and radially spaced relation therewith.

Abstract: Herein disclosed is a superconductive thin film formation method of forming a superconductive thin film having a high critical temperature and a low surface resistance. The method comprises a first step of depositing a superconductive thin film layer on a substrate under a first condition. The superconductive thin film layer has a thickness smaller than that of the superconductive thin film. The method further comprises a second step of introducing oxygen under a second condition. The method further comprises a third step of depositing a superconductive thin film layer on the previously deposited superconductive thin film layer under the first condition and fourth step of introducing oxygen under the second condition. The method further comprises a fifth step of repeating the third and fourth steps until the sum of the thicknesses of the superconductive thin film layers is substantially equal to the predetermined thickness of the superconductive thin film.

Abstract: Herein disclosed is a method for depositing a high Tc superconducting thin film. The superconducting thin film is deposited on one surface of a substrate. The substrate is exposed to an electromagnetic wave to heat the substrate during the process for depositing the superconducting thin film. Before the processes for depositing the superconducting thin film and exposing the substrate to the electromagnetic wave, a dummy film is formed on the other surface of the substrate. The dummy film has absorbency of the electromagnetic wave which is higher than that of the substrate. The dummy film together with the substrate is exposed to the electromagnetic wave while the superconducting thin film is deposited on the one surface of the substrate. The superconducting thin film thus deposited has superconductivity and high quality crystal structure.

Abstract: In a coaxial cable comprising a cylindrical conductor tube structure, a cylindrical core conductor arranged within the conductor tube structure, and a dielectric member provide between the conductor tube structure and the core conductor, the conductor tube structure is constituted by a cylindrical outer conductor and a cylindrical inner conductor provided within the outer conductor in coaxial and radially spaced relationship with the outer conductor to be capacitively coupled with the outer conductor. The inner conductor has a first axial end portion protruded axially outwardly from one end of the outer conductor and a second axial end portion received in the outer conductor retracted axially inwardly from the other end of the outer conductor. The outer and inner conductors of the conductor tube structure are thermally insulated from each other thereby reducing heat transmission between the outer and inner conductors without lessening conductivity for high frequency signals.

Abstract: Herein disclosed is a regenerative heat exchanger comprising a cylindrical core casing and a stack body core formed by a plurality of circular mesh plates each having fluid passage holes and stacked on one another to form fluid passageways. The stack body core is housed in the core casing to have a fluid cooling medium introduced into the fluid passageways to carry out heat exchange between the stack body core and the fluid cooling medium. Each of the mesh plates has on its outer periphery a reference mark portion positioned with respect to the fluid passage holes, and the mesh plates collectively form a row of reference mark portions indicative of the form of each of the fluid passageways. The row of reference mark portions enables to easily modify or adjust the shapes of the fluid passageways of the stack body core by relatively rotating the mesh plates with reference to the reference mark portions.

Abstract: To improve cooling efficiency of a pulse tube refrigerator, it is found that creating two conditions in the refrigerator, particularly in a regenerator is effective. In a first condition, working fluid in the regenerator should be compressed or expanded without having any displacement thereof, while it should be displaced without compression or expansion in a second condition. In order to realize this idea, a fluid displacement control valve assembly including two relief valves is disposed between a pulse tube and a buffer tank. Each of the relief valves is a normally closed one-way valve, and the valves open in opposite directions to one another when a pressure difference between the pulse tube and the buffer tank reaches a predetermined value, thus allowing the working fluid to be displaced after its compression from the pulse tube to the buffer tank and after its expansion from the buffer tank to the pulse tube.

Abstract: To improve refrigerating efficiency by preventing working fluid flowing into a pulse tube from a high-temperature end side thereof from reaching a cooling part in a cryogenic refrigerator, a ball-shaped travel member which has almost the same cross-section as the cross section of the pulse tube is inserted into the pulse tube and moves together with the working fluid therein. In this arrangement, when the working fluid begins to flow into the pulse tube from a flow rate regulation part on the high-temperature end side of the pulse tube, the travel member located within the pulse tube moves toward a cooling part together with the working fluid flowing in the pulse tube. Since the travel member has almost the same cross-section as the cross-section of the pulse tube, there is no possibility that the working fluid flows through between the inner wall of the pulse tube and the travel member.

Abstract: A superconducting oxide thin film device is composed of a LaAlO.sub.3 substrate and a YBCO thin film with a BaCeO.sub.3 buffer layer disposed between the two. The adhesion between the film and the substrate is increased by the presence of the buffer layer. The buffer layer also inhibits peeling of the film from the substrate and diffusion of Ba from the film into the substrate.