A noise filter includes a plurality of inductor elements connected with one another in series. The inductor element includes a ring-shaped magnetic core, a winding wound around the magnetic core, and a ground terminal disposed between the magnetic core and the winding, the ground terminal being connected to a ground. The ground terminal includes a conductive part that surrounds at least a part of an outer periphery of the magnetic core.

Disclosed herein is a common mode filter that includes first and second terminal electrodes provided on the first flange part, third and fourth terminal electrodes provided on the second flange part, a first wire wound around the winding core part and having one end connected to the first terminal electrode and other end connected to the third terminal electrode, and a second wire wound around the winding core part and having one end connected to the second terminal electrode and other end connected to the fourth terminal electrode. The winding core part includes a first winding region, a second winding region, and a third winding region positioned between the first and second winding regions in the axial direction. The first and second wires are bifilar-wound in the first and second winding regions and layer-wound in the third winding region.

A common mode noise filter includes a laminated body having insulator layers therein and first and second spiral conductors provided on layer planes different from each other. The first spiral conductor includes a first spiral conductor line, a first pad provided at an outer end of the first spiral conductor line, and a second pad provided at an inner end of the first spiral conductor line. The second spiral conductor includes a second spiral conductor line, a third pad provided at an outer end of the second spiral conductor line, and a fourth pad provided at an inner end of the second spiral conductor line. The first spiral conductor line faces the second spiral conductor line. Each of the second pad and the sixth pad overlaps none of the fourth pad and the eighth pad viewing from above.

An example wireless power transmitter may include a transistor configured to output an amplified signal, a first capacitor coupled to the transistor in parallel, a first LC resonant circuit coupled to the transistor in parallel, a third capacitor having a first end coupled to an output terminal of the transistor and the first LC resonant circuit, a feeding coil coupled to a second end of the third capacitor in series, and having at least a part configured to form a second LC resonant circuit with the third capacitor, and a transmission resonator including a transmission coil and a fourth capacitor coupled to the transmission coil in series. At least a part of the transmission coil may be magnetically coupled with the feeding coil, and at least a part of power received from the feeding coil may be output to an outside through the transmission resonator.

Systems and methods for enhanced high frequency power bias tee designs are provided. In one embodiment, a bias tee network comprises: a first port configured to couple across a data line comprising a first electrically conducting line and a second electrically conducting line; a second port configured to couple to a power port of an electrical device; and a distributed impedance interface coupled between the power supply unit and the differential data line, wherein the distributed impedance interface includes a ferrite impedance gradation network having a plurality of ferrite impedance elements series coupled in an order of progressing impedance, wherein a low impedance end of the first ferrite impedance gradation network is coupled to the first port.

A noise filter inserted between the power source side and the load side of a main circuit for which noise is reduced to attenuate noise of the main circuit using a filter circuit including the coil and the capacitor. In the noise filter, the board ground pattern is separated into a plurality of board ground patterns, the separated board ground patterns are connected to a common ground member present outside the board, the separated board ground patterns are formed as solid patterns, and adjacent board ground patterns of the separated board ground patterns are disposed so as to have a spacing equal to or less than a predetermined distance.

According to an aspect, an inductor damper circuit includes a shared magnetic core, a primary winding, and a secondary winding. The primary winding includes an inductor winding of a first wire gauge wound about the shared magnetic core. The secondary winding includes a resistive damper winding of a second wire gauge that is less than the first wire gauge and wound about the shared magnetic core in contactless magnetic coupling with the primary winding.

A board-type noise filter having higher noise removal performance than that of a conventional noise filter, and an electronic device including the board-type noise filter are provided. The board-type noise filter includes: a printed wiring board having a wiring pattern formed thereon; a choke coil including a core having a toroidal shape; a frame ground portion fixed to the printed wiring board at a position overlapping with a hollow portion of the choke coil when the toroidal shape of the choke coil is seen in plan view, the frame ground portion being capable of being grounded to a frame ground; and a capacitor having a first terminal connected to the frame ground portion through the wiring pattern.

Disclosed herein is a common mode filter that includes a winding core part and first and second wires wound in a same direction around the winding core part. The first and second wires constitute a first winding block on one endmost side in an axial direction of the winding core part, a second winding block on other endmost side in the axial direction of the winding core part, and a third winding block positioned between the first and second winding blocks. The second winding block is a winding block at an odd-numbered position counted from the first winding block. The first and second wires cross each other in an area between the first and third winding blocks and in an area between the second and third winding blocks.

Disclosed herein is a differential mode filter that includes first and second terminal electrodes provided on a first flange part of a core, and first and second wires wound around a winding core part of the core in an opposite direction to each other and connected respectively to the first and second terminal electrodes. The first and second wires cross each other on the winding core part to form a plurality of crossing portions that include first, second, and third crossing portions that are first, second, and third occurrences counting from the one end of the first and second wires, respectively. A first crossing angle between the first and second wires at the first crossing portion is larger than at least one of second and third crossing angles between the first and second wires at the second and third portions, respectively.