Tdk Corporation

Kazuaki Suzuki

Taro Miura

Makoto Kobayashi

Takahide Kurahashi

Hidenori Ohata

Makoto Hasegawa

Katsuhiko Igarashi

Tadao Fujii

Keizou Kawamura

Sakae Henmi

A non-reciprocal circuit element includes a microstrip TM resonator (n is a positive integer) with a metal disk and branches projecting from the metal disk in a trigonally symmetric structure, and a ferrite magnetic body spontaneously magnetized and coaxially disposed on the microstrip TM resonator. The metal disk and the branches are formed on a non-magnetic dielectric board having a ground conductor on its bottom face. The ferrite magnetic body is arranged so that a position of an electric field node matches to one of the branches.

Non-reciprocal circuit element and millimeter-wave hybrid integrated circuit board with the non-reciprocal circuit element

A multilayer ceramic part of the invention comprises an internal conductor layer and a ceramic layer which are formed by co-firing. The internal conductor layer is formed of an electrical conducting material containing silver as a main component, and the ceramic layer is formed of an yttrium-iron-garnet based oxide magnetic material with silver added thereto. Thus, the multilayer ceramic part can be fabricated in high yields, even when its size is much more smaller than that of a multilayer ceramic part fabricated until now.

Multilayer ceramic part

Conductor paste and multilayer ceramic part using the same

A multilayer ceramic part including dielectric ceramic layers and internal conductor layers is prepared by forming dielectric ceramic layers from an oxide system dielectric ceramic material having a sintering completion temperature between the melting point and the boiling point of the internal conductor. A pattern of internal conductor is formed on dielectric ceramic layers. The dielectric ceramic layers are placed one on another so as to sandwich the internal conductor pattern therebetween. The laminate is fired at or above the melting point of the internal conductor, optionally in an atmosphere having a controlled oxygen partial pressure. Since the dielectric ceramic material has an improved dielectric constant and dielectric loss and the internal conductor is densified and improved in surface property, the part is improved in resonator Q value and other properties. This minimizes the occurrence of defective parts in which the internal conductor is separated from the dielectric ceramic layer and minimizes a failure in the internal conductor layer.

Multilayer ceramic parts

A method of manufacturing a circulator includes the steps of forming, on at least one sheet (41, 42) of an insulating ferromagnetic material, dummy inner conductors (44a, 44b, 44c, 45a, 45b, 45e) made of a material which is thermally decomposed at a temperature equal to or less than a sintering completion temperature of the insulating ferromagnetic material, laminating a plurality of the sheets (40, 41, 42) of the insulating ferromagnetic material so that at least one insulating ferromagnetic material sheet (40, 41) covers the dummy inner conductors formed on the sheets (41, 42), firing the laminated insulating ferromagnetic material sheets (40, 41, 42) to form an insulating ferromagnetic material body (46) in a single continuous body and to form ducts (47) for inner conductors at portions occupied by the dummy inner conductors, injecting with pressure conductive paste into the ducts (47) in the insulating ferromagnetic material body (46), and firing the insulating ferromagnetic material body (46) to form the inner conductors (48) in the insulating ferromagnetic body (46).

Method of manufacturing microwave circulator

A circulator includes a circulator element (50) with inner conductors (41) having a predetermined pattern and an insulating ferromagnetic material body (40) closely surrounding the inner conductors. The insulating ferromagnetic material body is constituted by a fired single continuous body. The circulator also includes a plurality of terminal electrodes (76) formed on side surfaces of the circulator element and electrically connected to one end of the inner conductors, a plurality of circuit elements (51a, 51b, 51c) electrically connected to the terminal electrodes, and excitation permanent magnets (52, 53) for applying a dc magnetic field to the circulator element.

Growing community of inventors

Chiba, Japan

Kazuaki Suzuki