Ntt Docomo, Inc.

Ntt Mobile Communications Network, Inc.

Kei Satoh

Shoichi Narahashi

Daisuke Koizumi

Kunihiro Kawai

Tetsuo Hirota

Yasushi Yamao

Toshio Nojima

Hiroshi Okazaki

Ning Chen

Yoshiaki Tarusawa

Yuta Takagi

Noriyoshi Terada

Tatsuro Masamura

Tetsuya Mimura

An multiband resonator of the present invention includes a dielectric substrate including three or more dielectric layers, a ground conductor, a main-line conductor, a sub-line conductor, a sub open stub, a main open stub, a short-circuit conductor, a main through conductor, and a sub through conductor. The short-circuit conductor electrically connects one end of the main-line conductor to one end of the sub-line conductor and to the ground conductor. The main through conductor electrically connects the other end of the main-line conductor to one end of the main open stub that is aligned with that other end of the main-line conductor. The sub through conductor electrically connects the other end of the sub-line conductor to one end of the sub open stub that is aligned with that other end of the sub-line conductor.

Multiband resonator and multiband-pass filter

A dual-band bandpass filter according to the present invention includes a plurality of dual-band bandpass resonators. The dual-band bandpass resonator includes a central conductor having a central axis aligned with an input/output direction, a pair of grounding conductors, a central conductor short-circuit part and a pair of stub conductors that are formed on a surface of a dielectric substrate. The pair of grounding conductors are disposed on the opposite sides of the central conductor with a space interposed therebetween. The central conductor short-circuit part short-circuits the pair of grounding conductors, and one end of the central conductor is connected to the central conductor short-circuit part. The pair of stub conductors are disposed in the spaces on the opposite sides of the central conductor symmetrically with respect to the central axis of the central conductor, extend at least partially parallel with the central conductor and are connected to the central conductor short-circuit part at one ends thereof.

Dual-band bandpass resonator and dual-band bandpass filter

A signal selecting device according to the present invention has two input/output ports, a plurality of resonating parts, a plurality of impedance transforming parts, and a controlling part. The resonating parts have a ring conductor having a length equal to one wavelength at a resonant frequency or an integral multiple thereof and a plurality of switches each of which is connected to a different part of the ring conductor at one end and to a ground conductor at the other end. The controlling part controls the state of the switches. The resonating parts are disposed in series between the two input/output ports. The impedance transforming parts are disposed between the input/output ports in such a manner that the impedance transforming parts at the both ends are disposed between the input/output port and the resonating part and the remaining impedance transforming parts are disposed between the resonating parts.

Signal selecting device

A coplanar waveguide resonator () has a center conductor () formed on a dielectric substrate () that has a line conductor (a center line conductor) () extending in the input/output direction, a ground conductor () that is disposed on the dielectric substrate () across a gap section from the center conductor (), and a line conductor (a base stub) () formed as an extension line from the ground conductor (), and a part of the base stub () constitutes a line conductor (a first collateral line conductor) () disposed in parallel with the center line conductor ().

Coplanar waveguide resonator and coplanar waveguide filter using the same

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.

Signal switching device

A coplanar resonator which is comprised of a dielectric substrate, a center conductor formed in the surface thereof, and a ground conductor formed so as to surround the same center conductor, wherein the same center conductor is comprised of a main line conductor, formed by extension in a rectilinear shape, and auxiliary line conductorsandbifurcating from at least one end of the same main line conductor, folding back and being extended on both sides of the main line conductor.

Coplanar resonator and filter using the same

A signal input/output lineis used for input and output of a signal. A first resonating partis connected to the signal input/output lineat one end and is opened at the other end. A second resonating partis connected to a ground conductorat one end and is opened at the other end. A connecting linehas a predetermined length and is connected to a point of connection between the signal input/output lineand the first resonating partat one end and is connected to a predetermined point on the second resonating partat the other end.

Dual band resonator and dual band filter

A planar circuit housing () for containing a planar circuit () is disclosed. The planar circuit housing () comprises a support portion () for supporting edges of the planar circuit (), the support portion () being provided on at least one housing internal surface substantially perpendicular to the planar circuit substrate (); an upper cavity () in the housing () above the planar circuit (); and a lower cavity () in the housing () below the planar circuit (), the lower cavity () having the same sizes as the upper cavity () in directions parallel with the planar circuit substrate ().

Planar circuit housing

A coupling structure for coupling to a circuit portion () in a coplanar-waveguide circuit () having ground conductors () at both sides is disclosed. A signal input/output line () is provided at the center of the coplanar-waveguide circuit; and an inductive coupling portion () having an end of the signal input/output line short-circuited to one of the ground conductors and facing a part of the circuit portion via a first gap is also provided.

Coupling structure, resonator excitation structure and filter for coplanar-waveguide circuit

A filter is provided which comprises a single dielectric, and a line conductor and a ground conductor disposed on the dielectric. The line conductor includes first and second line conductor sections having opposed portions defining an open gap therebetween to form a capacitive coupling section. The edge lines of the opposed portions of the first and second conductor sections defining the open gap therebetween are substantially elongated relative to the line width of the corresponding conductor sections. The thus constructed filter is capable of suppressing a variation in the normalized J-inverter value even if dimensional errors relative to the design specifications due to overetching or underetching involved during the manufacture.

Filter with improved capacitive coupling portion

The invention relates to a high sensitivity receiver installed outdoors which may be used in a base station of a mobile communication system, for example. A received radio frequency signal is converted into a signal in a desired frequency band by a reception bandpass filter RXF, is subject to a low noise amplification to a desired level by a low noise reception amplifier LNA, and the amplified signal is converted into an optical signal by a laser diode LD. RXF, LNAand LDare confined in a heat shielding box. LDis cooled by cooling means to the order of critical temperature where RXF, for example, assumes a superconducting state, whereby the dynamic range is increased and stabilized.

High sensitivity radio receiver

A signal switching device is disclosed that is capable of transmitting signals with less signal loss while securing a good isolation characteristic. The signal switching device includes a first section formed from a superconducting material connected to a first transmission path. The first section has a smaller cross section at the input end than at the output end or, the signal switching device may include a first section formed from a superconducting material connected to a first transmission path in series, and a second section formed from a superconducting material connected to a second transmission path in parallel. The cross section of the second section is smaller than that of the second transmission path. The length of the second transmission path is determined in such a way that an input impedance of the second transmission path is sufficiently large when the second section is in a superconducting state.

A plurality of one-quarter wavelength coplanar resonatorstoare formed in series on a dielectric substrate, and coplanar input/output terminal sectionsandare formed on the dielectric substrate at opposite ends of the series connection for coupling with resonatorsand, respectively. A center conductor line width wof each of the resonatorstois equal to a center conductor line width wof each of the input/output terminal sectionand, but a ground conductor spacing dof each of the resonatorstois greater than a ground conductor spacing dof each of input/output terminal sectionandMaintaining the accuracy of design is facilitated and a reduction in the maximum current density in the resonator is enabled.

Coplanar waveguide filter and method of forming same

A filter is provided which maintains a low insertion loss characteristic of a filter contained in a casing with a very simple construction that the internal wall of the casing is formed by a superconductor. A coplanar waveguide filtercomprises a dielectric substrate, a plurality of resonatorsandand input/output terminal sectionsand, each of which is formed by a center conductorand ground conductorsand, both formed on the same surface of the dielectric substrate, with the ground conductorstobeing formed on the opposite sides of and in parallel relationship with the center conductor. The filteris contained within a casinghaving an internal wall, the surface of which is formed with a layer of superconductor. By way of example, a high temperature superconductor such as lanthanum-, yttrium-, bismuth- or thallium-superconductor is deposited as a film on a substrate of a metal oxide material such as MgO, SrTiO, LaGaO, LaAlOto provide a superconductor filmed substrate, which is applied to the internal surface of the casing. Electromagnetic power which is irradiated from the filterdoes not produce a power loss when it impinges on the layer of superconductorin its superconducting state, but is reflected therefrom to be absorbed by the filter, thus reducing the filter insertion loss.

Casing contained filter

A center conductor having a length L, which is equivalent in electrical length to one quarter wavelength, and ground conductors disposed on the opposite sides of the center conductor with a gap portion therebetween in coplanar manner are formed on a dielectric substrate. The center conductor and the ground conductors located on the opposite sides thereof, and are connected together by shorting ends. This results in the formation of corner areas, respectively, whereby obtaining a coplanar waveguide resonator. An edge line of the shorting end is recessed to have a curve configuration so that each corner area has an angle greater than 90 degrees, which reduces power current concentration at the corner points in the respective corner areas.

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Yokosuka, Japan

Kei Satoh