Abstract: Niobium or its alloy based Superconducting Radio Frequency (SCRF) Cavities involving atleast one laser beam welded components in the SCRF cavity welded from inside surface of the wall of cavity directed to achieving more than half the thickness to full depth penetration with minimum HAZ, minimizing distortion and shrinkage. The method ensures improved weld quality and surface finish substantially free of any weld defects. Also disclosed is the welding nozzle system and welding rigs adapted to facilitate such laser welding of the Niobium or its alloy based Superconducting Radio Frequency (SCRF) Cavities. The invention is thus directed to enhancing productivity, ensuring consistent quality and reliability, enhanced weld penetration with minimum HAZ, smooth finish of weld joints at possible reduced costs.

Abstract: Adaptations and improvements to tubular metal powder filters include employing a polyester binder or a binder formed of vacuum grease, employing metal powders of multiple different chemical compositions and/or spanning multiple different ranges of grain-size, replacing the outer conductive housing and metal powder components with a single structure formed of sintered metal powder, and texturing (such as rifling, threading, sanding, or scratching) an inner surface of the outer conductive housing. The various adaptations and improvements are designed to accommodate single-ended and differential signaling, as well as superconducting and non-superconducting applications.

Abstract: The present invention provides a resonator and a filter that reduce the resonator radiation loss so as to achieve a high Q value that is inherent to a low-loss material while maintaining high power handling capability. In this manner, both high power handling capability and a high Q value can be achieved at the same time. The resonator is a microstripline structure and includes a line structure formed with resonance lines in which current standing waves are generated in a resonant state in a line, and currents in each two adjacent lines flow in the opposite directions from each other, and a connection line that connects the resonance lines at the portions having in-phase voltages among the nodes of the current standing waves of the resonance lines in the resonant state. The filter includes resonators of the same type as the above resonator.

Abstract: A radio communication apparatus includes housings that are connected via a hinge unit in an openable/closeable manner, and circuit boards in the housings. The circuit boards are connected via circuit connecting lines functioning as an inductor. One end of the hinge unit is connected to an end portion of the housing and the other end thereof is connected to a portion located farther inside than an end portion of the housing. When the housings are unfolded, a region extending from the portion to the end portion of the housing overlaps a region near the end portion of the housing in a projection domain. A high dielectric member is provided in this overlapped region, and a capacitor is constituted by the high dielectric member and ground areas.

Abstract: Use, as a component with variable inductance which is a function of the current passing through it, of an inductive superconductive component having at least two terminals and comprising at least one line segment working with said terminals and integrating at least one of these terminals, this line segment constituting a conductive or superconductive layer within a stack of films alternately superconductive and insulating.

Abstract: The superconducting current-limiting device contains at least one coil (61), the conductive track of which is formed from at least one band-shaped superconductor (17), where a holding element (2, 41, 10, 51, 62) is located between adjacent coil windings. The holding element (2, 41, 51, 62) is constructed wider than the superconductor (17) in the axial direction of the coil (61). The holding element (2, 41, 51, 62) further includes a flat strip (11) and an undulating strip (12, 42, 52). The flat strip (11) extends essentially parallel to the band-shaped superconductor (17) at an essentially constant distance (22) therefrom. The undulating strip (12, 42, 52) extends essentially parallel to the flat strip (11), and in the longitudinal direction periodically has regions (15, 43, 53) distant from and regions (13) close to the flat strip (11). The regions (13) of the undulating strip (12, 42, 52) near to the flat strip have a mechanical connection (21) to the flat strip (11).

Abstract: This invention provides a thin superconducting oxide film, which can realize a high critical current, and a superconducting member having a high level of electric power resistance. The superconducting member comprises a sapphire R face substrate, a buffer layer formed of grain lumps of an oxide provided on the sapphire R face substrate, and a superconducting layer provided on the buffer layer. The nearest neighbor distance between oxygen atoms in the oxide and the grain diameter of grain lumps of the oxide have been specified. The superconducting member can be used as a member for superconducting filters.

Abstract: A method for production of hollow bodies, in particular for radio-frequency resonators is shown and described. The object to provide a hollow bodies and a resonator, respectively, having improved electrical properties is achieved by a method comprising the following steps: Providing a substrate having a monocrystalline region, defining a cut area through the substrate, fitting markings on both sides of the cut area, producing two wafers by cutting along the cut area, wherein the wafers are completely removed from the monocrystalline region, forming the wafers into half-cells, wherein the half-cells have a joining area, joining together the half-cells to form a hollow body, wherein the joining areas bear on one another, and wherein the markings on the half-cells are oriented with respect to one another on both sides of the joining area as on both sides of the cut areas.

Abstract: An electromechanical power converter that has a rotor assembly with a conductive shell, a first conductor made from superconducting material that is in series electrical contact with the conductive shell and a second conductor made from superconducting material and in series electrical contact with said conductive shell, thus providing an internal impedance converting electromechanical power converter.

Abstract: A narrowband filter tuned at a center frequency. The filter comprises an input terminal, an output terminal, and a plurality of resonators coupled in cascade between the input terminal and the output terminal. Each of the resonators is tuned at a resonant frequency substantially equal to the center frequency. The resonant frequencies of a primary set of the resonators and a secondary set of the resonators are of different orders.

Abstract: Adaptations and improvements to tubular metal powder filters include employing non-circular cross sectional geometries, aligning the inner conductor off-axis, replacing the inner conductive wire with a conductive trace carried on a printed circuit board, combining multiple filters within a single common outer conductive housing, and employing meandering and other non-parallel signal paths. The various adaptations and improvements are designed to accommodate single-ended and differential signaling, as well as superconducting and non-superconducting applications.

Abstract: According to an aspect of the present invention, there is provided a resonator including: a transmission line including a conductor line with a bent portion, wherein the conductor line has a plurality of slits formed therein, the slits being formed in an extending direction of the conductor line to pass through the bent portion, and wherein the slits are formed to have intervals that become narrower from an outer-side toward an inner-side of the bent portion.

Abstract: In a wall of a package base made of aluminum or aluminum alloy, there is formed a through-hole, through which a semi-rigid coaxial cable passes. A central conductor of the semi-rigid coaxial cable is joined to an electrode with a solder material. The semi-rigid coaxial cable has an insulating material through which the central conductor passes and an outer conductor provided therearound. The central conductor and outer conductor are made of stainless steel, for example, and the insulating material is made of fluororesin, for example. Inside the through-hole, the wall of the package base and the outer conductor are electrically connected to each other via a stainless material within the hole formed in a cylindrical fluororesin material. The semi-rigid coaxial cable and the like are fixed to the wall with a conductive screw.

Abstract: A resonance pattern (21) made of conductive material and having a circular plan shape is formed over the principal surface of a dielectric substrate. First and second virtual straight lines mutually crossing at a right angle are defined. A first input port (22) and a first output port (23) are electromagnetically coupled to the resonance pattern at two cross points between the first virtual straight line and an outer circumference line of the resonance pattern. A second input port (24) and a second output port (25) are electromagnetically coupled to the resonance pattern at two cross points between the second virtual straight line and the outer circumference line of the resonance pattern. A first inter-port waveguide (26) propagates a high frequency signal output to the first output port to the second input port.

Abstract: An apparatus and method for manufacturing a superconducting low-pass filter for quantum computing devices. The apparatus includes a plurality of containers and input and output ports connected to opposite ends of the apparatus. A plurality of coils of superconducting wire are wound using a mandrel. An adhesive is applied to the coils for maintaining a wound state. Each of the coils are positioned in each of the containers and electrically connected to each other with at least one coil being connected to the input port and at least one coil being connected to the output port. The coils are released or expanded from their wound state using an adhesive solvent. The containers are then filled with a conductive polymer and the containers are closed with one or more covers.

Abstract: There is provided a signal processing method comprising: inputting an input signal having a certain band; dividing said input signal into a signal in a stop band and a signal in a pass band outside said stop band with a use of a band stop filter which has a center frequency of said input signal inside said stop band and includes a first resonator having said center frequency as a resonance frequency; extracting a signal in a desired band from the signal in said pass band with a use of a plurality of second resonators; decomposing the signal in said stop band into signals whose degeneracy of said resonance frequency are released; combining a degeneracy-released signals and the signal in said desired band to obtain a combined signal; and outputting the combined signal.

Abstract: SQUIDs may detect local magnetic fields. SQUIDS of varying sizes, and hence sensitivities may detect different magnitudes of magnetic fields. SQUIDs may be oriented to detect magnetic fields in a variety of orientations, for example along an orthogonal reference frame of a chip or wafer. The SQUIDS may be formed or carried on the same chip or wafer as a superconducting processor (e.g., a superconducting quantum processor). Measurement of magnetic fields may permit compensation, for example allowing tuning of a compensation field via a compensation coil and/or a heater to warm select portions of a system. A SQIF may be implemented as a SQUID employing an unconventional grating structure. Successful fabrication of an operable SQIF may be facilitated by incorporating multiple Josephson junctions in series in each arm of the unconventional grating structure.

Abstract: A resonance pattern (21) made of conductive material and having a circular plan shape is formed over the principal surface of a dielectric substrate. First and second virtual straight lines mutually crossing at a right angle are defined. A first input port (22) and a first output port (23) are electromagnetically coupled to the resonance pattern at two cross points between the first virtual straight line and an outer circumference line of the resonance pattern. A second input port (24) and a second output port (25) are electromagnetically coupled to the resonance pattern at two cross points between the second virtual straight line and the outer circumference line of the resonance pattern. A first inter-port waveguide (26) propagates a high frequency signal output to the first output port to the second input port.

Abstract: A superconducting device comprises a dielectric substrate, and a plane-figure type resonator pattern made of a superconductive material and formed on a first face of the dielectric substrate. The resonator pattern has a notch at least a portion of which is round.

Abstract: A dual-mode filter capable of providing a high degree of design freedom and/or tunability is disclosed. The dual-mode filter includes a ring resonator; an input feeder and an output feeder disposed substantially orthogonal with respect to each other and with respect to the ring resonator so as to be electromagnetically coupled to the ring resonator; and a dual-mode generating line disposed inside the ring resonator in a manner so that the dual-mode generating line does not overlap with a line extending from the input feeder or a line extending from the output feeder.

Abstract: 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.

Abstract: The superconductive nanocomposite is a composition formed by nanoparticles of a high temperature superconductor blended with a polymer matrix containing natural rubber and polyethylene. The high temperature superconductor is preferably a bismuth-based superconductor (BSCCO) having a particle size of about 21 nm, but may be any other high temperature or Type II ceramic, metal oxide superconductor. The superconductor nanoparticles comprise about 15% of the weight of natural rubber in the composition. The polyethylene is preferably low density polyethylene and may comprise between 0% up to about 40% of the weight of natural rubber in the composition. The nanocomposite may be prepared by blending the components and roll milling the rubber.

Abstract: A signal switching device including a plurality of transmission paths connected to an input path, the signal switching device outputting a signal from the input path through one of the transmission paths, including a first variable impedance unit connected to a first transmission path, the first variable impedance unit including a first section formed from a superconducting material, the first section being set to a non-superconducting state when the signal is to be output through a second transmission path, the first section including a portion of a predetermined length at an input end, the portion having an area of a cross section less than an area of a cross section of the first section at an output end.

Abstract: Intermodulation distortion (IMD) is known to be an impediment to progress in superconductor-based filter technology. The present invention's methodology for reducing IMD can open doors to heretofore unseen practical applications involving high temperature superconductor (HTS) filters. Typical inventive practice includes (a) increasing the thickness d, and/or (b) changing the operation temperature T, of the filter's HTS film. The film's thickness d is increased in such a way as to decrease the IMD power PIMD in accordance with the material-independent proportionate relationship PIMD?1/d1.5-6. The film's operation temperature T is bettered or optimized in accordance with the material-independent proportionate relationship PIMD?(?O(T))10(K(2)(T))2/(?O(T))6, and further in accordance with three individual material-dependent relationships, namely, between operation temperature T and each of linear penetration depth ?O, gap maximum ?O, and kernel K(2).

Abstract: Fabrication methods for contoured polyhedral cavities for particle acceleration are disclosed. The process may include: trimming flat sheets to a conformal shape; bending the sheets to form a contour that is axially curved and azimuthally flat; and joining the sheets to form a circumferentially polyhedral cavity that is configured to support a resonant electromagnetic field at cryogenic temperatures. The resulting cavity may have ductile or even brittle superconducting materials with an axially-oriented grain structure at each point on the circumference of the cavity. As part of the assembly process, the sheets may be bonded to a supporting substrate of thermally conductive material having integrated cooling passages. The supporting substrates may be configured to have electrical contact near the cavity openings while having a small gap near the equators of the cavity. Moreover, mode-coupling channels and waveguides may be provided to extract energy from undesired deflection modes.

Abstract: A method and apparatus to provide appropriate coupling between resonators in an HTS microstrip filter are disclosed. Primary and secondary couplings between a pair of resonators are utilized. With a given spacing, the primary coupling is fixed, while the secondary coupling can have different magnitude. In addition, the secondary coupling can have the same phase or opposite phase as the primary coupling. With different combinations, large or small bandwidth filters can be made without very small or very large spacing between resonators. The same cross coupling layout configuration may be designed to achieve either positive or negative results.

Abstract: An apparatus for providing dynamic and remote tuning of a cryo-cooled bandpass filter is disclosed. The device includes resonator element and a voltage sensitive element as part of the capacitance in a narrow band filter circuit. A varactor such as a GaAs varactor may be used. Alternatively, a capacitor having a voltage-sensitive dielectric such as SrTiO3 may be used. A computer may be connected to the varactor to provide for automated tuning. The voltage-sensitive capacitor may be integral with the resonator element. The invention provides for remote and dynamic tuning of a narrow bandpass filter while located within its sealed cryo-cooled environment.

Abstract: A superconductive device that includes a ground film made of the superconductive material, wherein part of the ground film has an opening pattern.

Abstract: A superconductive filter includes a superconductive filter substrate having a dielectric substrate and a plurality of resonator patterns formed on a surface of the dielectric substrate, the plurality of resonator patterns including a superconductive material; a package accommodating the superconductive filter substrate; and an intermediate substrate disposed between an inner surface of the package and the superconductive filter substrate, and thermally coupling the package and the superconductive filter substrate wherein a difference between a degree of contraction of the intermediate substrate and the degree of contraction of the dielectric substrate is smaller than a difference between the degree of contraction of the dielectric substrate and the degree of contraction of the package, when the package, the intermediate substrate, and the dielectric substrate are cooled from room temperature to a critical temperature of the resonator patterns.

Abstract: The present invention relates to a method of preparing an oxide superconducting film, the method includes reacting a metal acetate containing metal M selected from the group consisting of lanthanum, neodymium and samarium with fluorocarboxylic acid having not less than three carbon atoms, reacting barium acetate with fluorocarboxylic acid having two carbon atoms, reacting copper acetate with fluorocarboxylic acid having not less than two carbon atoms, respectively, followed by refining reaction products, dissolving the reaction products in methanol such that a molar ratio of the metal M, barium and copper is 1:2:3 to prepare a coating solution, and coating a substrate with the coating solution to form a gel film, followed by calcining and firing the gel film to prepare an oxide superconducting film.

Abstract: A filter circuit includes an input terminal configured to input an input signal; first to ith blocks which have first to ith resonators as transmission lines having first to ith resonance frequencies; a power divider configured to distribute the input signal to the first to ith blocks; a power combiner configured to combine signals which have passed through the first to ith blocks to obtain a combined signal; and an output terminal configured to output the combined signal, wherein a jth block includes a phase adjustment unit which provides a signal of the jth block with a phase difference within a range of {(180±30)+(360×n)} degrees from a signal of a (j+1)th block, and a resonator having a large amount of group delay has a greater line width than a resonator having a small amount of group delay.

Abstract: A Radio Frequency (RF) component comprising a non-superconducting material, and a superconducting material, wherein the superconducting material is disposed in one or more areas of the RF component such that the areas with superconducting material conduct greater current density than do areas with the non-superconducting material.

Abstract: A resonator pattern made of superconductive material is disposed over a first surface of a base substrate made of dielectric. An adjustment substrate made of dielectric is disposed facing the first surface at a distance from the first surface. The adjustment substrate is supported by a support mechanism for supporting the adjustment substrate in such a manner capable of changing an angle between the first surface and a surface of the adjustment substrate facing the base substrate. A superconductive filter is provided which can shift a center frequency of a filter band and suppress disturbance of a waveform of a filter characteristic, with a simple method.

Abstract: A filter includes a dielectric substrate; an electrode layer continuously formed covering a first side of the dielectric substrate; a disk-shaped electrode pattern provided on a second side of the dielectric substrate, the disk-shaped electrode pattern and the electrode layer holding the dielectric substrate therebetween; a ground slot having an opening that is formed asymmetrically with respect to the center of a circular area included in the electrode layer and exposes the dielectric substrate, the circular area and the disk-shaped electrode pattern holding the dielectric substrate therebetween.

Abstract: Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

Abstract: An electromagnetic pulse protection circuit having wave filtering functions, composed of an LEMP protection circuit and a fast response protection circuit, and a filter is series-connected on a signal transmission route, and is utilized to provide impedance in effectively preventing electromagnetic pulses caused by lightning (LEMP) or other electronic weapon (NEMP, HEMP, PEMP) interferences. In addition, it is capable of suppressing electromagnetic pulses at specific frequencies, thus, raising the capability of electronic elements in resisting against electromagnetic pulses. Furthermore, said filter is made of high-temperature-super-conduction (HTSC) material, so that when said HTSC material of said filter is subject to a sudden infusion or invasion of said electromagnetic pulses, it is switched to a high impedance state in a very short period of time in effectively restricting currents passing through said filter, hereby avoiding the damages of a communication system.

Abstract: Between adjacent windings of a bifilar coil made of an HTS strip conductor in a resistive superconductive current limiter device, a spacer is provided which is transparent for a coolant. The spacer includes an electrically insulating support tape for sufficiently massive spacer elements attached thereon. The spacer elements are spaced and made of a material having high thermal conductivity. The spaces between the spacer elements form cooling channels for the coolant.

Abstract: A three-dimensional filter includes a pair of superconductor films opposed to each other, and a three-dimensional resonator made of dielectric and situated between the superconductor films, wherein one of the superconductor films is movable relative to the three-dimensional resonator.

Abstract: An inter-resonator coupling scheme for a filter is disclosed. An inter-resonator coupling member is located between successive resonators in the filter. By adjusting the length and/or the proximity of the inter-resonator coupling member relative to the adjacent resonators, the ratio of energy transferred from resonator to resonator (via the inter-resonator coupling member) may be increased and/or decreased. By increasing the ratio of energy transferred from resonator to resonator, the bandwidth of the filter is increased and is made relatively insensitive to tuning which may occur via manipulation of field disturbances introduced by tuning tips. The inter-resonator coupling member is made of a conductive or superconductive material and contains at least three sections. The first section runs substantially parallel to an edge of the first resonator that is not profoundly influenced by the source of field disturbance.

Abstract: The superconducting current-limiting device contains at least one coil (61), the conductive track of which is formed from at least one band-shaped superconductor (17), where a holding element (2, 41, 10 51, 62) is located between adjacent coil windings. The holding element (2, 41, 51, 62) is constructed wider than the superconductor (17) in the axial direction of the coil (61). The holding element (2, 41, 51, 62) further includes a flat strip (11) and an undulating strip (12, 42, 52). The flat strip (11) extends essentially parallel to the band-shaped superconductor (17) at an essentially constant distance (22) therefrom. The undulating strip (12, 42, 52) extends essentially parallel to the flat strip (11), and in the longitudinal direction periodically has regions (15, 43, 53) distant from and regions (13) close to the flat strip (11). The regions (13) of the undulating strip (12, 42, 52) near to the flat strip have a mechanical connection (21) to the flat strip (11).

Abstract: A superconducting device comprises a dielectric substrate, and a plane-figure type resonator pattern made of a superconductive material and formed on a first face of the dielectric substrate. The resonator pattern has a notch at least a portion of which is round.

Abstract: A superconducting tunable filter comprises a dielectric base plate; a patch-shaped resonator pattern formed of a superconducting material on the dielectric base plate; a top dielectric locally placed on the superconducting resonator pattern at a prescribed position and made of a material with an electric-field dependent permittivity; a conducting pattern formed on a top face of the top dielectric; and a bias voltage supply configured to apply a bias voltage between the conducting pattern and the superconducting resonator pattern.

Abstract: A superconducting tunable filter is disclosed that has a center frequency and a bandwidth able to be adjusted separately. The superconducting tunable filter includes a superconducting resonator filter pattern formed on a dielectric substrate; a dielectric or magnetic plate above the resonator filter pattern and having a through-hole; a dielectric or magnetic rod inserted in the through-hole; and a position controller which separately controls the position of the dielectric or magnetic plate and the position of the dielectric or magnetic rod relative to the resonator filter pattern.

Abstract: A superconducting filter device is disclosed that is able to prevent current concentration and improve electrical surface resistance. The superconducting filter device includes a first dielectric substrate, and a bulk superconducting resonator that is embedded in the first dielectric substrate and is formed from a bulk superconducting material.

Abstract: A superconducting device comprises a dielectric substrate, and a plane-figure type resonator pattern made of a superconductive material and formed on a first face of the dielectric substrate. The resonator pattern has a notch at least a portion of which is round.

Abstract: Provided is an optical module used in a communication system employing a radio over fiber (ROF) technology delivering a radio frequency (RF) signal through an optical fiber. The optical module includes: an optical device; a signal line for transporting a radio frequency (RF) signal input from an external circuit to the optical device; and a resistor separately disposed from the signal line and having one end connected with the optical device, wherein the input impedance seen from the signal line is matched by the resistor. A bias voltage supplied to operate the optical device is applied through an inductor connected to the signal line between the optical device and a filter. Here, the filter formed by a pattern of the signal line prevents the bias voltage from being supplied to the external circuit. In order to amplify the RF signal input from the external circuit, an amplifier may be connected between the external circuit and the filter.

Abstract: The present invention discloses a U-type superconductive microstrip resonator and a filter corresponding to the same. The U-type superconductive microstrip resonator is an asymmetric U-type configuration formed by folding the superconductive microstrip, its total length is a half of the wavelength corresponding to the center frequency of the filter constituted by them. A filter can be constituted by a number of said U-type superconductive microstrip resonators as required. In this filter, these U-type microstrip resonators are arranged in parallel in a manner that the longer sides direct a same direction, or in a manner that every two adjacent U-type superconductive microstrip resonators are symmetric about an axis. The filter constituted by said U-type superconductive microstrip resonators can not only achieve the same specification as an open-loop superconductive microstrip filter with a same number off sections, but also achieve a smaller size than the open-loop superconductive microstrip filter.

Abstract: The essence of the invention is the use of supercooled superconductors for generation of high-frequency electric oscillations. The superconductor is supercooled, i.e. in the normal phase at a temperature lower than the critical transition temperature for superconductivity, under an applied electric energy source. In such non equilibrium conditions the superconductor can have negative differential conductivity which can be used as an active medium in generators of electric (current and voltage) oscillations. Such generators can be used in the superconducing electronics. Oscillation can be modulated by the change of bias voltage, electrostatic doping by a gate electrode, or by light. When small amplitude oscillations are stabilized near to the critical temperature the generator can be used as a bolometer. The supercooled superconductors can be used also as transistors and frequency mixers. The negative differential conductivity of superconductor is created by the excess conductivity of fluctuation Cooper pairs.

Abstract: A comb limiter combiner for front end filtering reduces bit error rates with an increased reception range. Notch filters are tuned to suppress interfering frequency-hopped signals. An output comb filter suppresses out-of-band intermodulation products generated by any non-linear devices (such as limiters and the notch filters) in each of the comb limiter combiner sub-bands. Sensitivity is further increased by the use of cryogenically cooled high temperature superconductor components for the filters, amplifiers, and limiters used in each sub-band.

Abstract: A tunable RF filter comprises a signal transmission path having an input and output, a plurality of resonant elements disposed along the signal transmission path between the input and output, and a set of non-resonant elements coupling the resonant elements together to form a stop band having a plurality of transmission zeroes corresponding to respective frequencies of the resonant elements, and at least one sub-band between the transmission zeroes. The set of non-resonant elements comprises a first plurality of non-resonant elements respectively coupled in parallel with the resonant elements, and a second plurality of non-resonant elements respectively coupled in series with the resonant elements. The first plurality of non-resonant elements comprises at least one variable non-resonant element for selectively introducing at least one reflection zero within the stop band to create a pass band in one of the one sub-band(s) without varying any of the second plurality of non-resonant elements.