Abstract: A microwave filter is disclosed, which filters only a signal of a desired band in a radio communication system. The microwave filter includes a plurality of feed lines and resonators on an upper portion of a substrate, and a ground surface below the substrate. Each of the resonators includes coupled meander lines, the meander lines having three or more sections. The resonators are arranged in such a manner that the adjacent resonators are symmetrical to each other. The feed lines are formed at one side of the resonators at both edges, and are coupled spaced apart from the resonators in parallel to the resonators. Thus, the microwave filter can be fabricated at a small size because the meander-lined resonators have a small size. The microwave filter also has excellent transmission characteristics such as pseudo-elliptic characteristics.

Abstract: An electromagnetic resonator has a resonant element made of a high-temperature superconducting material such as YBa2Cu3O7-x. 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.

Abstract: A method and apparatus for the localized electrical fine tuning of passive multiple element microwave or RF devices in which a nonlinear dielectric material is deposited onto predetermined areas of a substrate containing the device. An appropriate electrically conductive material is deposited over predetermined areas of the nonlinear dielectric and the signal line of the device for providing electrical contact with the nonlinear dielectric. Individual, adjustable bias voltages are applied to the electrically conductive material allowing localized electrical fine tuning of the devices. The method of the present invention can be applied to manufactured devices, or can be incorporated into the design of the devices so that it is applied at the time the devices are manufactured. The invention can be configured to provide localized fine tuning for devices including but not limited to coplanar waveguides, slotline devices, stripline devices, and microstrip devices.

Abstract: An electromagnetic resonator has a resonant element made of a high-temperature superconducting material such as YBa2Cu3O7−x. 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.

Abstract: A tunable microwave monolithic integrated circuit includes a dielectric material with a variable dielectric constant. A superconducting material with a negative dielectric constant is provided which is arranged in relation to the dielectric material in such a way that at least one interface is formed between the superconducting material and the dielectric material. The dielectric material is a low loss non-linear bulk material. Phase velocity tuning of microwaves is provided through controlling the propagation of surface plasma waves of the microwaves along the interface(s).

Abstract: An arrangement for coupling electro magnetic waves, particularly microwaves, into and/or out of a device which includes a dielectric resonator having a non-linear dielectric substrate with a high dielectric constant and a coupling loop. The dimensions of the resonator and the coupling loop are related to the resonant frequency of the resonator. The coupling loop is so arranged in relation to the resonator that the magnetic field lines around the coupling loop match the internal film distribution of at least one mode, which has been selected to be excited, so that only that mode is excited. Coupling is provided only for this mode. The length of the coupling loop is comparable to or larger that the dimensions of the resonator.

Abstract: A high power filter apparatus which is used in a mobile communication base station or the like is provided wherein the temperature stability and frequency selection are excellent, an insertion loss is small, the size is small, power consumption is low and costs are low. A shield case block comprises signal input and output portions, and a plurality of closed spaces which house a filter element connected between the signal input and output portions. A cooling plate is provide in a heat insulating container which houses the shield case block. The shield case block is fixed to the cooling plate in the thermal contact state. Each filter element is place almost in parallel. A cylindrical hole having an axis which is almost parallel with the face of the filter element penetrates the shield case block. A ground rod made of a conductor which changes the volume of the closed space is provided on the inner end portion of a movable member which moves in the axial direction of the cylindrical hole.

Abstract: In a high frequency transmission line having a dielectric substrate and a conductor line which is provided on the dielectric substrate for allowing electric current to flow therethrough, the conductor line has a non-grain-boundary oxide superconductor layer with twin walls but without grain boundaries. The high frequency transmission line is in the form of a plane circuit. It is preferable that an oriented oxide superconductor layer is provided between the dielectric substrate and the non-grain-boundary oxide superconductor layer.

Abstract: An electrical interconnect provides a path between cryogenic or cryocooled circuitry and ambient temperatures. As a system, a cryocable 10 is combined with a trough-line contact or transition 20. In the preferred embodiment, the cryocable 10 comprises a conductor 11 disposed adjacent an insulator 12 which is in turn disposed adjacent another conductor 13. The components are sized so as to balance heat load through the cryocable 10 with the insertion loss. In the most preferred embodiment, a coaxial cryocable 10 has a center conductor 11 surrounded by a dielectric 12 (e.g. Teflon.TM.) surrounded by an outer conductor 13 which has a thickness between about 6 and 20 microns. The heat load is preferably less than one Watt, and most preferably less than one tenth of a Watt, with an insertion loss less than one decibel. In another aspect of the invention, a trough-line contact or transition 20 is provided in which the center conductor 11 is partially enveloped by dielectric 12 to form a relatively flat portion 28.

Abstract: A plurality of TEM mode transmission lines (L2-L5) are structured by pairs of thin film conductors (21 and 22, 22 and 23, 23 and 24, and 24 and 25) which sandwich thin film dielectrics (31 to 34) by alternately stacking the thin film conductor (21 to 25) and the thin film dielectric (31 to 34). The phase velocities of TEM mode waves which are propagated at least by two of the transmission lines (L2 to L5) are substantially equal to each other. The thickness of each of the thin film conductors (21 to 25) is smaller than the skin depth of the frequency used so that the electromagnetic fields of at least two TEM mode transmission lines among the TEM mode transmission lines (L2 to L5) are coupled to each other. In this way, the skin depth can be increased effectively. The conductor loss and the surface resistance can be reduced significantly as compared to those of the conventional electrode. By use of this electrode, a transmission line, a resonator, a filter, and a high frequency device are structured.

Abstract: In a ferrite switchable microwave device, a magnetic structure is formed in a nearly continuous closed-loop configuration of a single crystal material, or of a material exhibiting the magnetic properties of single crystal materials (quasi-single crystal materials). A magnetization M is induced in the structure. The toroidal shape of the structure in combination with the properties of the magnetic material results in a device which exhibits virtually no hysteresis. The device is operable either in a fully magnetized state or in a partially magnetized state. In a fully magnetized state, the device operates in the region of magnetic saturation. The absence of hysteresis in the device enables switching between the positive and negative magnetic saturation points with very little energy. In a partially magnetized state, the device provides a variable magnetization M between the two saturation points.

Abstract: 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.

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: A planar filter for performing signal filtering at radio frequencies is provided. The planar filter can include asymmetrical resonators, wherein each resonator is asymmetrical about a longitudinal center axis through the resonator. In addition, the resonators can be grouped in coupled pairs such that the resonators in each coupled pair are asymmetrical about a longitudinal center axis between the paired resonators. In addition, a coupling structure is provided that includes both distributed coupling and tapped coupling to a resonator. Further, a bandstop filter device is provided that includes coupling between resonators in the filter.

Abstract: A lanthanum aluminate (LaAlO.sub.3) substrate on which thin films of layered perovskite copper oxide superconductors are formed. Lanthanum aluminate, with a pseudo-cubic perovskite crystal structure, has a crystal structure and lattice constant that closely match the crystal structures and lattice constants of the layered perovskite superconductors. Therefore, it promotes epitaxial film growth of the superconductors, with the crystals being oriented in the proper direction for good superconductive electrical properties, such as a high critical current density. In addition, LaAlO.sub.3 has good high frequency properties, such as a low loss tangent and low dielectric constant at superconductive temperatures. Finally, lanthanum aluminate does not significantly interact with the superconductors. Lanthanum aluminate can also used to form thin insulating films between the superconductor layers, which allows for the fabrication of a wide variety of superconductor circuit elements.

Abstract: A method of producing ceramic superconducting materials such as YBa.sub.2 Cu.sub.3 O.sub.x includes blending together starting materials for the superconducting material. The blend of starting materials are formed into a layer and sintered at a temperature above the peritectic temperature for the superconducting material. Prior to sintering, the starting materials for the superconducting material may be unreacted. The starting materials may also be partially reacted prior to sintering by calcining for a period of time at a temperature which does not result in full reaction of the starting materials to the chemical composition of the desired superconducting material.

Abstract: Superconducting multiplexing/demultiplexing arrangements include a number of signal input devices and a number of signal output devices. A number of resonators provides a number of filters. Each filter represents a channel. The resonator(s) operate(s) devices at lest in dual mode, and tuning devices are provided so that at least some of the resonators is/are tuneable. A method is provided of multiplexing signals incoming to a multiplexing arrangement with a number of resonators, each of the resonators having a number of input ports which are so arranged that a number of mulitpole filters are created. Input signals having different frequencies are supplied to the different input ports of the resonators, each of which is operated in three modes. Coupling devices are arranged which at least comprise the angle between the input ports and a symmetry plane. The angles are non-perpendicularly azimuth.

Abstract: A superconducting notch or band reject filter arrangement includes a superconducting dielectric resonator and a waveguide arrangement including a microstrip line to which the resonator is connected. The resonator is a parallel-plate resonator with a chip of a non-linear dielectric material device on which superconductors are arranged and the waveguide arrangement includes a contact device or a coupling device, the resonator being connected to the contact device of the waveguide arrangement in such a way that electric contact is provided, and the filter arrangement is frequency tuneable. Through the arrangement, the insertion losses are low.

Abstract: High temperature superconductor mini-filters and mini-multiplexers utilize self-resonant spiral resonators and have very small size and very low cross-talk between adjacent channels.

Abstract: The present invention provides an electronically tunable resonating apparatus which uses a tunable dielectric material which is biased by an electric field to alter the resonant frequency in a resonating cavity. The electrodes which apply the electric field are connected to a variable voltage source. The electrodes can therefore apply a plurality of electric field strengths and provide a range of resonant frequencies in the resonating apparatus. The resonating apparatus is particularly useful for microwave and millimeterwave electromagnetic energy.

Abstract: A narrow bandwidth (1 to >100 MHz) HTS microwave filter (30 or 50) is described which is tunable over a moderate frequency range (100 to >1000 MHz at X-band). The low loss (<1 dB) and GHz/microsecond tuning rates enable the filter to operate as a radar preselector filter. The filter consists of a multi-pole microstrip or stripline HTS coupled one-half resonator pattern deposited onto a ferrite substrate (32 or 52, 54). The ferrite substrate is operated in a latching mode like that in the operation of digital phase shifters. The filter tunability arises from the variation of the effective permeability with the remanent magnetization.

Abstract: A resonant structure has a center conductor, a dielectric element, and an outer conductor. The center conductor is a substrate with a coating of a superconductor on its outer surface, and the outer conductor is a substrate with a coating of a superconductor on its inner surface. The dielectric element has a passageway which is sized for receiving the inner conductor so that there is substantially complete contact between the layers of superconductor coating and the dielectric. Similarly, the outer surface of the dielectric element is sized to match the inner superconductor coated surface of the outer conductor.

Abstract: A ferroelectric phase shifter in the form of a coplanar waveguide and a method of fabrication thereof in which a ferroelectric film and a high temperature superconductor film are deposited onto a substrate in of a number of configurations. The high temperature superconductor material is biased in order to vary the dielectric constant of the ferroelectric material. Changing the dielectric constant enables varying the amount of phase shift of a wave applied to the phase shifter.

Abstract: A symmetrical coplanar waveguide is formed by a spiral with three arms. One arm is 1, the second arm is 2 and the 3rd arm is 41. The arms 1 and 2, and spiral arms 1 and 41 are separated by equal distance. The spiral arms 1, 2 and 41 are formed by the deposition of films of a conductor, layer 3, on a film 14 of a single crystal ferroelectric material, layer 2, which is deposited on a single crystal dielectric material, layer 1. Input is 10 and the output is 11. The CPW spiral arms 1, 2 and 41 form a time delay device. When a bias voltage V is applied between the spiral arms 1 and 2, and between 1 and 41 through a bias filter made of L and C, the permittivity of the ferroelectric film between the spiral arms 1 and 2, and between 1 and 41 or across the CPW, changes producing a change in the time delay.

Abstract: A superconductor layer is formed on one side of a dielectric substrate, and with this superconductor layer as a conductor layer of the bottommost layer, superconductor layers and dielectric layers are alternately laminated with each other. Thus, a superconducting multilayer electrode is provided which is laminated with at least one TEM mode transmission line which is constituted of a pair of superconductor layers with a dielectric layer sandwiched in between, and the superconductor layer and the dielectric layer have film thicknesses which are set so that the maximum value of the current density flowing through each superconductor layer becomes the same. The resistance to electric power of the superconducting multilayer electrode is proportional to the number of laminated layers.

Abstract: A microwave filter has a plurality of resonators and at least one transmission line mounted on a substrate having a ground plane. The filter can have input and output couplings that are transmission lines formed on the substrate or it can have input and output probes. The resonators have one or more gaps extending entirely therethrough, the gaps splitting the resonators into two or more slices. The transmission lines extend into the gap to couple energy into or out of a resonator or between two adjacent resonators. The transmission lines can have tapered ends or can be located off center so that they are closer to one side of a gap than to another side.

Abstract: The pass band filter has planar ring resonators arranged in pairs partly side-by-side and partly one above the other and a housing cover for each resonator. Each resonator includes a respective substrate provided with upper and lower conductive layers of high temperature superconductor material on respective opposite sides of the corresponding substrate, so that each planar ring resonator is operable in an edge-current-free TM010-oscillator mode. A respective coupling hole of radius r.sub.i is provided in the lower conductive layer (3) of each resonator and the lower conductive layers of both resonators in each pair face each other so that both resonators are coupled. Each housing cover has a respective truncated cone-shaped step ring (20) having a corresponding inner housing cover radius (r.sub.G). The radius ratio r.sub.i /r.sub.a (r.sub.

Abstract: An electrically tunable planar filter has a filter element including a substrate having an upper side and a wave-guide arranged on the upper side of the substrate, at least one tuning element composed of at least one material selected from the group consisting of a ferroelectric material and an antiferroelectric material with adjustable voltage applied to the tuning element and thereby with an adjustable dielectric constant, the tuning element being arranged at the upper side of the substrate.

Abstract: A high power high temperature superconductive circuit for use in various microwave devices including filters, dielectric resonator filters, multiplexers, transmission lines, delay lines, hybrids and beam-forming networks has thin gold films deposited either on a substrate or on top of the high temperature superconductive film. Alternatively, other metal films can be used or a plurality of dielectric films can be used or a dielectric constant gradient substrate can be used. The use of these materials in a part or parts of a microwave circuit reduces the current density in those parts compared to the level of current density if only high temperature superconductive film is used. This increases the power handling capability of the circuit.

Abstract: A coplanar waveguide is formed by a spiral with two arms. One arm is labelled 1, and the second arm is labelled 2. The arms labelled 1 and 2 are separated by equal distance. The spiral arms labelled 1 and 2 are formed by the deposition of a film of a conductor, a third layer, on a film 14 of a single crystal ferroelectric material, a second layer, which is deposited on a single crystal dielectric material, a first layer 1. Input is 10 and the output is 11. The CPW spiral arms labelled 1 and 2 forms a time delay device. When a bias voltage V is applied between the two spiral arms labelled 1 and 2 through a bias filter made of an inductor L and a capacitor C, the permittivity of the ferroelectric film between the two spiral arms labelled 1 and 2, or across the CPW, producing a change in the time delay.

Abstract: Novel structures and methods for forming useful high temperature superconducting devices, most particularly resonators, are provided. Structures resulting in reduced peak current densities relative to known structures achieve numerous desirable benefits, especially including the reduced intermodulation effects of earlier resonators. In one aspect of this invention, a spiral in, spiral out resonator is provided, characterized in that it has an odd number of long runs, at least equal to five long runs, where the long runs are connected by turns, and wherein there are at least two sequential turns of the same handedness, followed by at least two turns of the opposite handedness. In yet another aspect of this invention, it has been discovered that reducing the size of the input and output pads of HTS resonators increases the relative inductance compared to the capacitance. Yet another resonator structure is a spiral snake resonator having a terminal end disposed within the resonator.

Abstract: 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.

Abstract: In a small transmission line type high-frequency circuit element that has small loss due to conductor resistance and has a high Q value, an error in the dimension of a pattern, etc. can be corrected to adjust element characteristics. An elliptical shape resonator (12) that is formed of an electric conductor is formed on a substrate (11a), while a pair of input-output terminals (13) are formed on a substrate (11b). Substrate (11a) on which resonator (12) is formed and substrate (11b) on which input-output terminal (13) is formed are located parallel to each other, with a surface on which resonator (12) is formed and a surface on which input-output terminal (13) is formed being opposed. Substrates (11a) and (11b) that are located parallel to each other are relatively moved by a mechanical mechanism that uses a screw and moves slightly. Also, substrate (11a) is rotated by the mechanical mechanism that uses a screw and moves slightly around the center axis of resonator (12) as a rotation axis (18).

Abstract: The present invention provides a superconducting transmission delay line phase shifter which has an essential structure as follows. The superconducting transmission delay line phase shifter has a layer made of a material showing a low dielectric loss the layer comprising first, second and third sections, wherein the second section being positioned between the first and third sections. The superconducting transmission delay line phase shifter also has a ferroelectric selectively provided in the second section. The ferroelectric extends between boundaries of the second section to the first and third sections. The superconducting transmission delay line phase shifter also has a thin film made of a conductor having a high conductivity. The conductive thin film extends across the bottoms of the first, second and third sections. The superconducting transmission delay line phase shifter also has a superconducting signal transmission line, on which signals are transmitted.

Abstract: An NRD waveguide band-pass filter apparatus is provided which is simple in construction, which can be easily manufactured as well as being small in size and light in weight, and which operates in a single operating mode. The NRD waveguide band-pass filter apparatus includes a plurality of NRD waveguide resonators arrayed in such a way that each two adjacent NRD waveguide resonators are electromagnetically coupled to each other. A plurality of arrayed rectangular dielectric waveguides are interposed between an upper surface portion and a lower surface portion of a rectangular dielectric housing, which are parallel to each other. The upper surface portion and the lower surface portion and the plurality of arrayed rectangular dielectric waveguides are formed integrally, thus forming the housing. A first superconducting electrode and a second superconducting electrode are formed on the outer surfaces of the upper surface portion and the lower surface portion, respectively.

Abstract: A planar dual mode filter has one or more resonators with L-shaped sections that are oriented back to back to one another. The filter can be constructed by adjusting the size of a gap between the back to back sections and adjusting the offset distance between adjacent sections. Further, coupling between adjacent resonators can be controlled by adjusting a distance between the adjacent resonators. The filters can be co-planar, stripline, suspended microstripline or microstripline. The filters have a film on a substrate with a ground plane. The film can be gold, silver or copper or it can be a ceramic material that becomes superconductive at cryogenic temperatures.

Abstract: 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.

Abstract: A high-temperature superconductive microwave delay line that operates in an essentially pure TEM field configuration in a compact assembly. The delay line is a planar signal delay line which includes first and second substrates made of first and second dielectric materials; each substrate can be LAO material. First and second patterned delay line segments having a configuration, are formed of first and second conductive materials on the obverse sides of the first and second substrates, respectively. On the reverse side of each of the first and second substrates, respective first and second ground planes are formed using respective first and second conductive materials, which are preferred to be high-temperature superconductive films, such as YBCO films. The delay line also includes coupling means for coupling the first patterned delay line segment to the second patterned delay line segment, thus bringing the two patterned delay line segments into substantial contact.

Abstract: A tuning mechanism for tuning a resonant circuit is provided. The tuning mechanism comprises a spring pin having a superconductive, dielectric or magnetic tuning tip attached thereto. The spring pin is slidably inserted into a filter package wall through a mating hole. A mechanism is provided for adjusting the position of the tip within the electromagnetic field above the filter element. The tip may be shaped, thus allowing adjustment of both the height of the tip above the filter element and the position of the tip in a plane parallel to the plane of the filter. Optionally, the spring pin may include an offset to allow close spacing of the tips along with wider spacing of the actuator end of the pin.

Abstract: A first electrically conductive layer whose thickness is equal to or smaller than the skin depth of the radio wave used for communication, a dielectric layer whose permittivity is changed by application of electric field, and a second electrically conductive layer whose thickness is equal to or smaller than the skin depth of the radio wave used for communication are sequentially stacked near a resonance element which is formed on the front surface of a dielectric substrate having a ground layer formed on the rear surface thereof. The effective permittivity of the dielectric layer is changed in a wide range by changing a voltage applied between the first and second electrically conductive layers to change the electric field applied to the dielectric layer. As a result, the impedance of the resonance element is changed, and when a plurality of resonance elements are arranged closely to each other to construct a filter, the coupling degree between the resonance elements is changed.

Abstract: A method for forming a superconducting device using a selective etching technique on superconducting thin films. The method utilizes rapid etching which combines ion implantation with chemical etching. The portions of the superconducting film to be retained are masked from the ion implantation process. The chemical etching process then removes the implanted portions of the superconducting film at a much faster rate than the portions not implanted so that only the un-implanted portions remain. The resulting superconducting devices can be used, e.g., as nanostructures and nano tips, bolometers, multilayer RF coils, microwave waveguides and filters.

Abstract: Disclosed is a planar dual mode microstrip filter with the coupling between similar modes on different patches governed by the spacing between the patches rather than by microstrip coupling lines between the patches. The patches are shaped to allow dual mode coupling. The materials used in building this filter were an alumina substrate with gold metalization. The filter is encased in a conducting box made from a conducting material. One advantage of the proximity coupled structure is that it reduces the number of parts, complexity and allows the filter to be realized in a smaller space than in previous dual mode designs. This filter is useful in satellite communications, radar, and cellular communications. High temperature superconductor materials can be used in a planar microstrip form.

Abstract: The high power band-pass filters are made of sections of circular waveguide resonators with sections of waveguide in between them. In the center of the waveguide resonator a ferroelectric disc, with a hole in the center, is placed. A bias is applied to the inner side of the ferroelectric disc. On the application of a bias voltage, the permittivity of the ferroelectric disc changes. As a result, the resonant frequency of the circular cavity changes. Application of different levels of bias voltages produces different resonant frequencies of the filter. The interior conducting surfaces of the waveguide(s) and the waveguide resonator(s) have high Tc superconducting material and the waveguide flanges have high Tc superconducting material on the conducting surfaces.The band-stop filters are made of a section of a main waveguide with branch waveguide resonator(s) connected on the broad-wall of the main waveguide with waveguide sections in between the resonators.

Abstract: A bandstop filter contains one or more resonant circuits connected by interconnecting transmission lines. The resonant circuits each have a transmission line connected between two capacitors. One capacitor is connected to the interconnecting transmission line and the other capacitor is connected to ground. The resonant circuits may have a helical coil of superconducting materials as the transmission line. The capacitors may be in the form of screws, which can be inserted into or removed from the center of the helix. The helix may be formed as a discrete structure and supported by a low-loss material within a housing.

Abstract: Microstrip/stripline transmission lines have a plurality of strips on a substrate where strips are separated by a gap. This arrangement results in a reduced maximum current density compared to previous transmission lines with the same power handling capability. The strips can have the same width or different widths. The gaps can have the same width or different widths. The transmission lines can be used in filters and resonators and can be made of high temperature superconductive materials.

Abstract: A filter for processing electromagnetic signals has a housing with resonators located inside the cavity of that housing. The resonators, which may be made in part from superconducting material, have rounded exterior surfaces without corners to provide a more desirable coating surface and uniform electric field around the resonators. The filter housing may be composed of a plurality of housing cells, each containing a resonator. These cells can be removably attached to other cells so that resonators may be added to or removed from the filter as may be required for a particular application.

Abstract: A material formed as a film comprised of monomolecular layers (2,3,4,5) stacked on a substrate (1), wherein said film includes at least one first set (R) of layers which form an electric charge reservoir, and a second set (S) of layers which form a conductive cell and which contain a number of conductive copper oxide layers (4), separated from each other by intermediate layers (5), the reservoir and the conductive cell being adjacent in the layer stack. There are at least four conductive copper oxide layers, and the intermediate layers have the chemical formula Ca.sub.1-x M.sub.x and are free of strontium, wherein x is a real number between 0 and 0.2, M is a component with an ionic radius close to that of the Ca.sup.2+ ion, and the intermediate layers may be complete or not.

Abstract: TM.sub.0i0 mode (i=1, 2, 3, . . . ) planar high temperature superconductor resonators useful in high temperature superconducting filters, filter banks and multiplexers comprise a shaped high temperature superconductor film and a high temperature superconductor ground plate deposited on opposite sides of a dielectric substrate, wherein the shaped high temperature superconductor film has an aperture in the center thereof and has a shape selected from the group consisting of circles and polygons.

Abstract: This invention pertains to monolithic filters of the band-pass or band-reject type which a single crystal ferroelectric material having an electric field dependent permittivity. The filters are comprised of: a first layer of a single crystal dielectric material; a second layer of a single crystal high T.sub.c superconductor material; a third layer of a single crystal ferroelectric material; and a fourth layer of high T.sub.c superconductive microstrip lines configured into the various filter circuits, including resonator circuits and transformer circuits. The filters are capable of operating at power levels up to 0.5 MW at a temperature slightly above the Curie temperature to avoid hysteresis.

Abstract: A coaxial cavity is loaded with a single crystal ferroelectric rod whose permittivity is dependent on the electric field in which it is immersed. Application of a bias voltage changes the permittivity of the ferroelectric rod of the cavity and thus changing the frequency of the coaxial cavity. A tunable coaxial filter is obtained. By placing the cavity in the main transmission line, a bandpass tunable filter is obtained. By placing the cavity in a branch line, a band reject tunable filter is obtained.