Alps Electric Co., Ltd.

Yuichi Shimizu

Eiichi Komai

Nobuhiko Suzuki

Takamitsu Shibayama

A method of manufacturing a magnetic sheet includes a slurry sheet forming step, a local magnetic field applying step, and a slurry curing step. In the slurry sheet forming step, slurry is formed by mixing flat soft magnetic metal powder in a binding material, and a slurry sheet is formed by shaping the slurry into a sheet. In the local magnetic field applying step, only the orientation of the flat soft magnetic metal powder, which exists in the partial area, of the entire flat soft magnetic metal powder mixed in the slurry sheet is unified in a predetermined direction by locally applying a magnetic field to a partial area of the expanded slurry sheet in a predetermined direction. In the slurry curing step, a magnetic sheet is formed by curing the slurry sheet after the local magnetic field applying step.

Method of manufacturing magnetic sheet

An antenna coil formed on a substrate surface of an insulating substrate has conductor lines forming four sides of a basic loop shape. Furthermore, the antenna coil has corner lines at a corner portion of the loop. For example, by forming trimming lines on the inner side of one of the corner lines, it becomes possible to adjust the resonant frequency in various ways without considerably disturbing the shape of distribution of magnetic flux density generated by the antenna coil as a whole.

Adjustable antenna coil

Provided is a nonreciprocal circuit element which has increased lengths of central conductors to be compatible with miniaturization while exhibiting superior performance. In the nonreciprocal circuit element, a first yoke has a rectangular upper plate, a pair of side plates bent downward from sides of the upper plate facing each other, and notch parts formed at the central portion of the pair of side plates. Ends of a magnet are placed within the notch parts. Thus, the magnet can be enlarged and a ferrite member provided corresponding thereto can also be enlarged. Accordingly, the lengths of conductors of central conductors mounted on the ferrite member are increased, thereby achieving high performance while not adversely affecting miniaturization.

Nonreciprocal circuit element with notch part in yoke

A non-reciprocal circuit element includes first, second, and third central conductors, which are formed of thin films or thick films. Each of the first, second, and third central conductors includes a first extended portion which extends from one end of the corresponding central conductor and which is disposed on a side surface of the ferrite part and a second extended portion which extends from the other end of the corresponding central conductor and which is disposed on the side surface of the ferrite part. The adjacent first and second extended portions face each other with a second dielectric part formed of a thin film or a thick film disposed therebetween, and hence a capacitor is formed between the adjacent first and second extended portions. Without using known chip capacitors, the capacitors are thinly formed, leading to reduction in cost and size of the non-reciprocal circuit element.

Small non-reciprocal circuit element with good productivity

An irreversible circuit device with small insertion loss and excellent isolation is to be provided. An irreversible circuit device according to the invention has a flat plate shaped ferrite member and first, second and third central conductors placed on the ferrite member. In the central conductors, second conductor parts are placed on the ferrite member as input or output first conductor parts are placed on notch parts of the ferrite member. Therefore, when a magnetic flux passes through V-shaped extension parts as a magnetic path, the current generation is reduced and the energy transmission is increased in the first conductor part placed therebetween. Consequently, the insertion loss is reduced, and the isolation becomes excellent.

Irreversible circuit device with small insertion loss and excellent isolation having a Y-shaped ferrite

A planar magnetic core is disposed in a DC magnetic field, and the top surface thereof is perpendicular to the direction of the DC magnetic field. Three central conductors are placed on the top surface of the magnetic core so that they overlap with each other at regular intervals substantially at the center of the top surface of the magnetic core. One end of each of the central conductors is used as an input/output terminal, and the other ends thereof are used as ground terminals. The inductance per unit length of the central conductor from the central portion to the ground terminal is set to be smaller than that from the central portion to the input/output terminal.

Small-loss, large-return-loss nonreciprocal circuit device

An isolator has a magnetic core of a plate shape placed within a direct current magnetic field and having an upper face perpendicular to the direction of the direct current magnetic field, and first to third central conductors overlapping other at an equal angle interval approximately in the central portion of the upper face of the magnetic core, and having one end connected to the ground. The other end of the first central conductor is an input terminal, and the other end of the second central conductor is an output terminal. At least the third central conductor is constructed by two parallel band-shaped conductors. One end of one band-shaped conductor is connected to the ground by a first resistor and a first capacitor. The other end of the other band-shaped conductor is connected to the ground by a second resistor and a second capacitor. The capacity value of the first capacitor and the capacity value of the second capacitor are different from each other.

Isolator for greatly attenuating signal transmitted in reverese direction over wide frequency band

An electronic circuit unit having a circulator is formed of a circuit board made by laminating a plurality of dielectric substrates; first, second, and third central conductors disposed at intervals of 120 degrees on a plurality of dielectric substrates and partially intersecting in the upper and lower directions; a magnet and a ferrite member disposed above and below the intersection of the central conductors; a first yoke covering the outside of the magnet; and a second yoke covering the outside of the ferrite member. One end of each of the central conductors serves as an input and output terminal, and the ends are disposed at intervals of 120 degrees. Adjacent input and output terminals are connected by inductive elements.

Growing community of inventors

Fukushima-ken, Japan

Yuichi Shimizu