109 results about "Ferrite bead" patented technology

An apparatus and method for minimizing electromagnetic interference in a microcomputing system. The apparatus and method of the present invention are based on the fundamental aspect of providing an EMI shield specifically dimensioned to receive a microprocessor within the microcomputing system. The apparatus and method of the present invention are further based on the aspect of providing at least one ferrite bead along a power delivery path to attenuate any high-frequency leakage current from the microprocessor that results at the resonant frequencies of the EMI shield.

A soldering apparatus for connecting solar cells includes an induction heat source to connect cell conducting tracks, provided with soldering medium, with electric conductors. The heat source has a high-frequency generator and an inductor loop in which the flow of a high-frequency current causes a high-frequency magnetic field to induce in the conducting track and in the electric conductor arranged along the conducting track eddy currents that generate the heat that is necessary for the soldering operation. The inductor loop includes a U-shaped loop element that has narrowings and widening in one arm that is positioned closer to the conductor. Ferrite beads and ferrite tubes at the widening concentrate the magnetic field to optimize the heat development in the soldering zone and thus also save energy.

An end-fed sleeve dipole is provided herein with improved impedance match and increased bandwidth by incorporating a ¾-wavelength transformer in the antenna design. The ¾-wavelength transformer is compatible with a number of different choking schemes, including but not limited to, a single ¼-wave choke sleeve, a single ¼-wave choke sleeve with additional ferrite beads, and two or more ¼-wave choke sleeves with or without ferrite beads. In some embodiments, one or more shunt resonators may be used to provide additional impedance compensation.

A filtered connector with multiple pin contacts (14) connected to ground by Pi filters, which can be constructed at low cost. Two circuit board portions (24, 26) that are spaced apart by ferrite beads (40), are portions of a single flexible circuit board (50) that are connected together by a loop portion (52) of the circuit board. A ground plane (100) of the circuit board is connected to a metal shell (130) that surrounds the circuit boards and pins, by bending peripheral portions (140, 142) of the circuit board as it is pressed into the shell and soldering the peripheral portions to the shell. Each of the pins is connected to a signal trace (80, 82) on the circuit board by the hole edge of each circuit board being deflected out of its original plane by the pin, to assure the flow of solder between the signal trace and the pin.

A high-frequency signal amplifier circuit is used in a front-end circuit configured to propagate a high-frequency transmission signal and a high-frequency reception signal, and includes an amplifier transistor configured to amplify the high-frequency transmission signal; a bias circuit configured to supply a bias to a signal input end of the amplifier transistor; and a ferrite bead, one end of which is connected to a bias output end of the bias circuit and the other end of which is connected to the signal input end of the amplifier transistor, having characteristics in which impedance in a difference frequency band between the high-frequency transmission signal and the high-frequency reception signal is higher than impedance in DC.

A directional bridge coupler includes a coaxial balun having a coaxial cable with a plurality of ferrite beads disposed about an outer conductor of the coaxial cable, and a circuit substrate accommodating a directional bridge coupled to an output of the coaxial bridge. A conductive package having an internal cavity houses the circuit substrate and the coaxial balun. A polyiron saddle straddles a portion of the coaxial balun within the internal cavity of the conductive package.

A probe card includes low-voltage and high-voltage source pins and a plurality of signal pins. An EMI filter block is electrically connected between each source pin and a corresponding card terminal. Each EMI filter block includes a plurality of EMI filter elements connected in parallel. The low-voltage EMI filter element includes a three-terminal capacitor and a ferrite bead separately disposed, whereas the high-voltage EMI filter element includes a three-terminal capacitor having a built-in ferrite bead.

An apparatus for time-gated fluorescence or luminescence detection includes gating means (206) arranged to alternately permit light from an excitation source (242) to be directed to a sample (235) along a first communication path (231, 232), and then permit light emitted from the sample to be directed to a detector (246) along a second communication path (237, 238) while blocking the first communication path (231, 232): The gating means (206) may comprise a single chopper wheel or apertured disc, or a rotating or oscillating arm, and may further comprise one or more reflective facets (207). The gating means (206) may be driven via a magnetic rotor, with a ferrite bead placed to offset rotor magnets with respect to drive coils, when at rest, so as to assist with self starting.

A headphone receiver apparatus for use with low power transmitters includes a pair of headphone speaker enclosures connected by a headband. An antenna element in the form of a spring steel band or a plastic cable/antenna band where one of the conductors is utilized as the antenna is configured generally concentric with but offset from the headband and the user's head by at least 0.5 inches over at least some length of the antenna. Low-noise performance is improved by a low noise amplifier incorporated before the receiver IC, and a bandpass filter interposed between the low noise amplifier and the receiver IC. A base-loading inductor is used to tune the antenna element to resonance, with or without capacative end-loading. Lumped inductors, ferrite beads, or a parallel resonant LC circuit may be used to isolate the shield conductor at RF frequencies, and/or to reduce the loading of the other conductors.

The invention discloses an integral type anisotropic multipolar ferrite bead and a preparation method thereof. The ferrite bead is composed of main composition and auxiliary composition. The main composition comprises ferric oxide and SrO by mass ratio of 1:5.5-1:5.7. On the basis of the sum of the mass of all main composition, the auxiliary composition comprises 0.35%-0.50% of kaolin, 0.40%-0.60% of calcium carbonate, and 1.0%-5.0% nanometer inorganic fluxing agents. According to the integral type anisotropic multipolar ferrite bead, residual magnetism Br is larger than or equal to 400mT, coercive force Hcb is larger than or equal to 245kA/m, intrinsic coercive force Hcj is larger than or equal to 250kA/m, and a maximum magnetic energy product (BH) is larger than or equal to 30kJ/m3.

An optical pickup with a laser driver circuit is provided to overcome an increase in size of an optical pickup, which is caused by a ferrite bead or capacitor being provided in a drive current path to reduce EMI noise effects. In an optical disc apparatus, an optical sensor element detects a laser beam from a laser emission element included in an optical pickup circuit and then sends the detected signal to a main circuit board. An APC circuit in the main circuit board outputs a control signal to control the laser output from the laser emission element at a constant level in accordance with the detected signal from the optical sensor element. A laser driver circuit included in the optical pickup circuit incorporates a transistor and a high-frequency wave superposition circuit). The transistor produces a drive current in accordance with the control signal from the APC circuit, while the high-frequency wave superposition circuit superposes a high-frequency current on the drive current. The drive current superposed with the high-frequency current drives the laser emission element.

A noise filter has an element body, first to fourth terminal electrodes, and a connection conductor. The first to fourth terminal electrodes are disposed on the exterior of the element body. The connection conductor is also disposed on the exterior of the element body. A capacitor is formed in the element body and is electrically connected between the first and second terminal electrodes and the third and fourth terminal electrodes. The first and second terminal electrodes are electrically connected through the connection conductor. The connection conductor is covered by a resin containing ferrite. Since the connection conductor is covered by the resin containing ferrite, the connection conductor and the ferrite-containing resin function as a ferrite bead inductor.

A circuit includes an electronic component package that comprises at least a first lead, a III-N device in the electronic component package, a gate driver, and a ferrite bead. The III-N device comprises a drain, gate, and source, where the source is coupled to the first lead. The gate driver comprises a first terminal and a second terminal, where the first terminal is coupled to the first lead. The ferrite bead is coupled between the gate of the III-N transistor and the second terminal of the gate driver. When switching, the deleterious effects of the parasitic inductance of the circuit gate loop are mitigated by the ferrite bead.

The invention discloses a ferrite material, small large-current laminated-chip wideband magnetic beads, and a preparation method thereof. The ferrite main materials comprise: 49-55mol% of Fe2O3, 25-35mol% of ZnO, 4-8mol% of CuO, 8-15mol% of NiO, 0.1-0.6mol% of Co3O4, 1-3mol% of Bi2O3, and 0.5-1.5mol% of Nb2O5. The magnetic bead preparation method comprises the steps of ferrite slurry preparation, material band dry preparation, cutting, ferrite material sheet punching, ferrite material sheet printing, ferrite material sheet lamination, cutting and forming, and the like. With the ferrite material, magnetic saturation degree is improved, and direct current resistance is reduced, such that larger current can be withstood. According to the magnetic bead preparation method, production period is shortened, and production efficiency is improved. The volume of the magnetic beads is small. The magnetic beads have good electromagnetic interference inhibition capacity from 100MHz to higher than 1GHz.

The invention discloses a preparation method for a sintering permanent magnetic ferrite ring of a brushless motor, and an objective is to provide a preparation method for a sintering permanent magnetic ferrite bead of a brushless motor, and the method improves magnetic flux density and solves a problem that cracking is easy to occur in a sintering process. The main technology comprises pre-magnetizing blank, breaking and preparing materials, drying and sintering, grinding, and magnetizing, so as to prepare and produce a multipolar magnetic ring whose peak value is 2000 Gs after magnetizing, and solve problems that the inner and outer circles of the magnetic crack caused by the difference value of shrinking percentages in a sintering process of a multipolar molded workblank body. Beneficial effects of the method are that the problems that the inner and outer circles of the magnetic crack caused by the difference value of shrinking percentages in a sintering process of the multipolar molded workblank body is solved, the method ensures the hardness of a mold cavity and service life of moulds, greatly restrains magnetic ring products from cracking in sintering, and improves magnetic flux density of a multipolar radiation magnetic ring.

A semiconductor structure having an in situ chip-level ferrite bead inductor and method for forming the same. Embodiments include a substrate, a first dielectric layer formed on the substrate, a lower ferrite layer formed on the first dielectric layer, and an upper ferrite layer spaced apart from the lower ferrite layer in the structure. A first metal layer may be formed above the lower ferrite layer and a second metal layer formed below the upper ferrite layer, wherein at least the first or second metal layer has a coil configuration including multiple turns. At least one second dielectric layer may be disposed between the first and second metal layers. The ferrite bead inductor has a small form factor and is amenable to formation using BEOL processes.

In an optical module in which a transmitter and a receiver that respectively outputs and receives optical signals are stored in a casing, the transmitter and the receiver are connected to a common power line and to a common ground line, and a ferrite bead is arranged on the ground line in the receiver. The ferrite bead absorbs a high-frequency current component out of components in an electric signal passing through the ground line on which the ferrite bead is arranged. An inductance component that evolves on a ground line and a power line of a light receiving element and oscillation of a series resonance circuit that is formed of a capacitance component of the light receiving element are suppressed to reduce crosstalk.

A method for selecting a ferrite bead for a filter to avoid a peak value in a frequency response curve of the filter is provided. The method includes the steps of: building an equivalent model database including parameters of equivalent models of ferrite beads, the parameters including an inductance and a capacitance of a corresponding equivalent model of each ferrite bead; calculating parameters of a desired ferrite bead in the filter based on parameters of the filter, the parameters of the ferrite bead including an inductance, a capacitance, and a resonant frequency; adjusting parameters of the filter until the calculated resonant frequency equals or approaches a desired resonant frequency, and finding an inductance and a capacitance respectively equaling or approaching the calculated inductance and the calculated capacitance in the database; and selecting a ferrite bead with the appropriate inductance and capacitance as found in the database for the filter.

The invention allows the fabrication of small, dense, highly polished spherical beads of hexagonal ferrites with selected compositions for use in nonreciprocal microwave and mm-wave devices as well as in microwave absorbent or reflective coatings, composites, and the like. A porous, generally spherical bead of hydrous iron oxide is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead is washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) under conditions of elevated temperature and pressure to convert the bead into a mixed hydrous iron-alkaline earth oxide while retaining the generally spherical shape. This mixed oxide bead is then washed, dried, and calcined to produce the desired (BaFe12O19 or SrFe12O19) crystal structure. The calcined bead is then sintered to form a dense bead of the BaFe12O19 and SrFe12O19 phase suitable for polishing and incorporation into various microwave devices and components.

An EMI energy absorber for use with an electrical circuit, such as a hot wire air flow sensor, which has at least one electrical element which exhibits antenna characteristics at a predetermined frequency range for the EMI. The energy absorber includes a component, such as a ferrite bead, which is electrically connected in series with the element of the electrical circuit. This component exhibits a resistance which varies as a function of frequency and has a maximum resistance within the predetermined frequency range. Thus, the component functions to absorb the EMI and dissipate the EMI as heat.

In a noise filter, an input side of a signal-line lead is inserted in a first substantially cylindrical ferrite bead, and an output side of the signal-line lead is inserted in a second substantially cylindrical ferrite bead. An input side of a ground lead is inserted in a third substantially cylindrical ferrite bead. The signal-line lead is inserted in a feedthrough capacitor such that the feedthrough capacitor is adjacent to an output side of the second substantially cylindrical ferrite bead. A multilayer capacitor is electrically coupled between the signal-line lead and the ground lead such that the multilayer capacitor is adjacent to an output side of the first substantially cylindrical ferrite bead and adjacent to an output side of the third substantially cylindrical ferrite bead. Each of an end of the signal-line lead and an end of the ground lead is flat, bent along an outer surface of a base member, and defines a surface-mount external terminal.