Hitachi Metals, Ltd.

Hitachi, Ltd.

The University of Tokyo

Dowa Electronics Materials Co., Ltd.

Nippon Ferrite, Ltd.

Hitachi Ferrite, Ltd.

Hitchi Metals, Ltd.

Shigeru Takeda

Yasuaki Kinoshita

Kohei Ito

Yasuhide Murakami

Sadami Kubota

Satoshi Makio

Yasushi Kishimoto

Shinji Yamamoto

Hiroyuki Itoh

Koji Ichikawa

Shin-ichi Ohkoshi

Hideto Horiguchi

Shinichirou Takeuchi

Hideto Mikami

Shuichi Watanabe

Takashi Tsuboi

Yukinori Arita

Kouji Ichikawa

[Problem] When a nonreciprocal device operating at 100 GHz to 300 GHz is to be realized by using a conventional magnetic material of garnet-type ferrite or spinel-type ferrite, a huge permanent magnet is required and, therefore, it is very difficult to achieve a millimeter-wave band nonreciprocal device for practical use. [Solving means] To solve this problem, there is provided a millimeter-wave band nonreciprocal device composed of a magnetic material represented by a formula &#x3b5;-MFeO(0&#x3c;x&#x3c;2), wherein M is at least one of elements In, Ga, Al, Sc, Cr, Sm, Yb, Ce, Ru, Rh, Ti, Co, Ni, Mn, Zn, Zr, and Y and the magnetic material having &#x3b5;-phase hematite as a principal phase exhibits strong coercive force and anisotropic magnetic field at room temperature. Dimensions of a magnetic circuit containing a permanent magnet for operations of the nonreciprocal device can be made remarkably small and, by optimum design, the use of the magnetic circuit can be made unnecessary.

Millimeter wave band nonreciprocal device

A non-reciprocal element with three central conductors and a communication apparatus are disclosed, in which the insertion loss is small and the bandwidth is wide. Three central conductors are arranged in proximity to a ferrite thin plate in such a manner as to cross each other in a mutually electrically insulated state. A static magnetic field is applied to the ferrite thin plate by a permanent magnet. An end each of the three central conductors makes up three input/output terminals, respectively, and the other end thereof is connected to a common portion. Three matching capacitors are connected between an end each of the three input/output terminals, respectively, and the common portion. At least one of the angle between the first and second central conductors and the angle between the second and third central conductors is not more than 90 degrees.

Non-reciprocal element with three central conductors and communication apparatus using the same

A two-port isolator comprising a thin ferrite plate, a permanent magnet for applying a static magnetic field to the thin ferrite plate, first and second central conductors disposed substantially in a center portion of the thin ferrite plate and crossing each other with electric insulation, first and second input-output terminals each connected to an end of each of the first and second central conductors, a common terminal connected to the other ends of the first and second central conductors, a first matching capacitor connected between the first input-output terminal and the common terminal, a second matching capacitor connected between the second input-output terminal and the common terminal, and a resistor connected between the first input-output terminal and the second input-output terminal, wherein the DC resistance of the resistor is set, such that with loss in a high-frequency signal entering into the first input-output terminal and exiting from the second input-output terminal defined as insertion loss, and with loss in a high-frequency signal entering into the second input-output terminal and exiting from the first input-output terminal defined as isolation loss, the insertion loss is smaller than the isolation, and that the isolation loss increases as a static magnetic field applied to the two-terminal isolator from outside increases.

Two-port isolator and method for evaluating it

A concentrated constant, non-reciprocal device comprising a permanent magnet for applying a DC magnetic field to a ferrimagnetic body, an assembly in which at least a part of a plurality of center conductors one end of which serves as a common terminal and the other of which serves as a first input/output terminal is wound on or embedded in the ferrimagnetic body, a plurality of second input/output terminals, a plurality of impedance converting circuits connected between the second input/output terminals and the first input/output terminals, respectively, and a plurality of load capacitors connected between the first input/output terminals and the common terminals, respectively. The input impedance Z of the corresponding first input/output terminal at the operating center frequency and an external impedance Z connected with the corresponding second input/output terminal satisfy 0.05&lE;Z /Z &lE;0.9. As a result, it is possible to provide a small concentrated constant circulator/isolator of a wide band width having excellent electric characteristics.

Concentrated constant irreciprocal device

A process managing apparatus in a computer system for supporting an information processing system development. This process managing apparatus comprises a combination defining information storing unit for storing information defining a predetermined combination of process management information for managing processes of the information processing system development; a process management information acquiring unit for acquiring process management information in accordance with a process for creating specifications such as drawings and documents; and process management information editing unit for selecting and editing predetermined process management information from among said acquired process management information on the basis of said combination defining information.

Apparatus for dynamically collecting and editing management information

A magnetostatic wave microwave device comprising a thin magnetostatic wave element and a conductor disposed on the top of said magnetostatic wave element. Because the width of an junction portion of the conductor is larger than the width of an input portion of the conductor, a large impedance change of the magnetostatic wave element at resonance can be obtained while maintaining a Q-value at a high level.

Magnetostatic microwave device having large impedance change at resonance

A magnetostatic wave device has a nonmagnetic substrate, a magnetic thin film formed on the nonomagnetic substrate, and a plurality of electrodes. By applying a magnetic field from the outside in parallel with or perpendicularly to the magnetic thin film, a magnetostatic wave is excited in the magnetic thin film and is propagated. The magnetostatic wave is coupled with a microwave signal generating circuit by a plurality of (n) electrodes. The plurality which are arranged at positions where the microwave signal is not substantially coupled with the second to (n+l)th order mode of the magnetostatic wave.

Magnetostatic wave device with minimized higher order mode excitations

A magnetostatic wave device comprises a magnetic thin film formed on a non-magnetic substrate, one or a plurality of electrode fingers and pad electrodes formed on the above described magnetic thin film, a magnetostatic wave resonator for exciting and propagating a magnetostatic wave within said magnetic thin film and for causing resonance, and a matching stub connected to at least one of the above described pad electrodes of the above described magnetostatic wave resonator to adjust the impedance of the magnetostatic wave device.

Magnetostatic wave device

A Faraday rotator device containing (a) a Faraday rotator, (b) a wire winding encircling the Faraday rotator for changing the magnetization state of the Faraday rotator, and (c) a hollow yoke surrounding the Faraday rotator and the wire winding for forming a substantially closed magnetic circuit together with the Faraday rotator, the hollow yoke having an opening in each of front and rear walls in alignment with the Faraday rotator for permitting a light to pass through the hollow yoke and the Faraday rotator. The optical switch containing a pair of polarizers disposed on front and rear sides of the Faraday rotator device, the magnetization direction of the Faraday rotator being reversible to change the optical path. The hollow yoke is made of a soft magnetic material or a semi-hard magnetic material.

Faraday rotator device and optical switch containing same

A chip for a magnetostatic wave device comprising; a base substrate consisting of a dielectric monocrystalline base plate and a ferrimagnetic monocrystalline film formed on the base plate; an excitation means for magnetostatic waves formed on the ferrimagnetic film when it is given a bias magnetic field and high frequency electric signals; and a reflection means to reflect the excited magnetostatic wave toward the center portion of the film before it reaches at end portions of the ferrimagnetic film.

Magnetostatic wave device and chip therefor

A magnetostatic wave band-pass-filter is disclosed which uses a planar structure, it has, a single crystal thin film formed on a single crystal gadolinium gallium garnet substrate and mainly containing yttrium iron garnet. In this band-pass-filter, input and output electrodes each made up of finger electrodes and pad electrodes are formed on the substrate or thin film, a high-frequency signal is applied to the input electrode, to excite a magnetostatic wave in the thin film, the magnetostatic wave is reflected from parallel straight edges of the thin film, to generate resonance, and a high-frequency current excited by the magnetostatic wave is taken out by the output electrode.

Magnetostatic wave band-pass-filter

A resonance absorption-type microstrip line isolator including a ground conductor; a magnetic member provided on the ground conductor; and a central conductor provided on the magnetic member, portions of the magnetic member on both sides of the central conductor being magnetized oppositely. The magnetic member may be replaced by a composite member constituted by at least two magnetic members and at least one nonmagnetic dielectric member. Further, to achieve the miniaturization of the isolator, the central conductor may be in a meandering shape.

Resonance absorption-type microstrip line isolator

An optical isolator comprising a cylindrical magnet magnetized in a direction parallel to the axis of rotational symmetry thereof, a Faraday rotator disposed in a center space of the cylindrical magnet, a pair of beam splitters capable of serving as a polarizer or an analyzer arranged on both sides of said Faraday rotator with inclination of 45.degree. relative to each other, characterized in that the outer diameter Do, the inner diameter Di and the length L of the cylindrical magnet are in the range defined by ##EQU1## where .alpha.=Do/Di. In the case of a multi-stage optical isolator, the Faraday rotators and the beam splitters are arranged alternately in tandem, and any two adjacent cylindrical magnets are arranged with their magnetic poles of the same polarity facing each other.

Growing community of inventors

Kumagaya, Japan

Shigeru Takeda