A BALUN transformer core material contains a Z-type hexagonal system ferrite having an in-plane anisotropy and a high magnetic permeability and such a high resonance frequency as to be in excess of a Snake's limiting line, and therefore, in the BALUN transformer core material, the frequency properties of the magnetic permeability are extremely good. A BALUN transformer core obtained by pressing and sintering this BALUN transformer core material has a high initial magnetic permeability and specific resistance. Moreover, a BALUN transformer obtained by applying a winding to the BALUN transformer core is provided with superior properties which are not poorer as compared with a BALUN transformer constituted of a conventional spinel ferrite, and it is a BALUN transformer having high properties which can be used in a high-frequency band of 300 MHz or more.

BALUN transformer core material, BALUN transformer core and BALUN transformer

The manganese-zinc system ferrite of the invention has an initial permeability μi at a frequency of 100 kHz and at 25° C. of 5,000 or more, and a core loss Pcv at a frequency of 100 kHz and at 200 mT and 40° C. of 400 kW/m 3 or less.

Manganese-zinc system ferrite

PROBLEM TO BE SOLVED: To provide a Mn-Zn ferrite having high electrical resistance and exhibiting sufficient durability even when it is used in a high frequency region over 1 MHz. SOLUTION: This composition of fundamental components is 44.0-50.0 mole % Fe2O3, 4.0-26.5 mole % ZnO, 0.1-8.0 mole % of one kind or two kinds of TiO2 and SnO2, 0.1-16.0 mole % CuO and the balance MnO. By the addition of TiO2, SnO2 and CuO, the Mn-Zn ferrite having an electrical resistance of >=103 times of that of a conventional Mn-Zn ferrite and exhibiting a high initial permeability of 300-400, which has been previously estimated, at the high frequency of 5 MHz can be obtained, even at the time of firing at a low temp. in the atmosphere.

Mn-Zn ferrite

A MnZn ferrite having excellent characteristics of an incremental permeability µΔ value of 250 or greater in a wide temperature range of 0 to 85°C and an incremental permeability µΔ value of 400 or greater at 65°C when an 80 A/m direct current magnetic field is applied is provided. The MnZn ferrite has basic components that comprise: ferric oxide (in terms of Fe 2 O 3 ): 51.0 to 54.5 mol%, zinc oxide (in terms of ZnO): 8.0 to 12.0 mol%, and manganese oxide (in terms of MnO): the balance, sub components that comprise: silicon oxide (in terms of SiO 2 ): 50 to 400 mass ppm, and calcium oxide (in terms of CaO): 50 to 400 mass ppm, and unavoidable impurities phosphorous, boron, sulfur and chlorine that are restricted to phosphorous: less than 3 mass ppm, boron: less than 3 mass ppm, sulfur: less than 5 mass ppm, and chlorine: less than 10 mass ppm.

Mnzn ferrite and magnetic core for transformer

An electrically conductive material configured having at least one opening of various unlimited geometries extending through its thickness is provided. The opening is designed to modify eddy currents that form within the surface of the material from interaction with magnetic fields that allow for wireless energy transfer therethrough. The opening may be configured as a cut-out, a slit or combination thereof that extends through the thickness of the electrically conductive material. The electrically conductive material is configured with the cut-out and/or slit pattern positioned adjacent to an antenna configured to receive or transmit electrical energy wirelessly through near-field magnetic coupling (NFMC). A magnetic field shielding material, such as a ferrite, may also be positioned adjacent to the antenna. Such magnetic shielding materials may be used to strategically block eddy currents from electrical components and circuitry located within a device.

Wireless System Having a Substrate Configured to Facilitate Through-Metal Energy Transfer Via Near Field Magnetic Coupling

PURPOSE: To cut down power loss in a high-frequency region by a method wherein specific amounts of silicon oxide, calcium oxide, tin oxide and/or titanium oxide, niobium oxide. zirconium oxide are contained in the material of ferrite. CONSTITUTION: As for the main components, mangenese oxide, zinc oxide and iron oxide are contained and as for the sub components, silicon oxide, calcium oxide, tin oxide and/or titanium oxide, niobium oxide and zirconium oxide are contained. At this tiem, the contents of mangnese oxide in the main contents is 30-41mol% in terms of MnO, 6-16mol% of zinc oxide in terms of ZnO. On the other hand, the weight ratio of the sub components to the main components is 50-250-ppm of silicon oxide in terms of SiO 2 , 200-1500ppm of calcium oxide in terms of CaO, not exceeding 4000ppm of tin oxide in terms of SnO 2 , not exceeding 3000ppm of titanium oxide in terms of TiO 2 and the total of the tin oxide and titanium oxide exceeds 3000ppm. COPYRIGHT: (C)1995,JPO

Ferrite and ferrite core for power supply

of EP0707323A ferrite having low power losses, high DELTA B = Bm - Br at high frequency, and improved mu a-B properties is provided as well as a core for a power supply using the same. The ferrite contains 30-41 mol% of MnO, 6-16 mol% of ZnO, and the balance of Fe2O3 as main components and 50-250 ppm of SiO2, 200-1500 ppm of CaO, up to 4000 ppm of SnO2, up to 3000 ppm of TiO2, at least 300 ppm of SnO2 + TiO2, from more than 0 to 500 ppm of Nb2O5, and from more than 0 to 400 ppm of ZrO2 as subordinate components.

Ferrite and ferrite core for switching power source

A manganese-zinc ferrite having an initial magnetic permeability νi of 5000 or above at a frequency of 100 kHz and a temperature of 25 °C, and a core loss Pcv of 400 kW/m3 or less at a frequency of 100 kHz, 200 mT and 40 °C.

Manganese-zinc ferrite

A ferrite which is reduced in power loss and has a large value of ΔB (= Bm - Br) in the high-frequency range and a satisfactory νa-B relationship, and a power source core made therefrom. The ferrite is composed of the chief component comprising 30-41 mole % of MnO, 6-16 mole % of ZnO and the balance consisting of Fe2O3 and the subsidiary component comprising 50-250 ppm of SiO2, 200-1,500 ppm of CaO, at most 4,000 ppm of SnO2, at most 3,000 ppm of TiO2 (provided the sum of SnO2 and TiO2 is at least 300 ppm), at most 500 (exclusive of 0) ppm of Nb2O5, and at most 400 (exclusive of 0) ppm of ZrO2.

Osamu Takeda

Papers

Manganese-zinc system ferrite

Ferrite and ferrite core for power supply

Ferrite and ferrite core for switching power source

Manganese-zinc ferrite

Ferrite and ferrite core for power source