An electrostatically tunable magnetoelectric inductor including: a substrate; a piezoelectric layer; and a magnetoelectric structure comprising a first electrically conductive layer, a magnetic film layer, a second electrically conductive layer, and recesses formed so as to create at least one electrically conductive coil around the magnetic film layer; with a portion of the substrate removed so as to enhance deformation of the piezoelectric layer. Also disclosed is a method of making the same. This inductor displays a tunable inductance range of >5:1 while consuming less than 0.5 mJ of power in the process of tuning, does not require continual current to maintain tuning, and does not require complex mechanical components such as actuators or switches.

An electrostatically tunable magnetoelectric inductor including: a substrate; a piezoelectric layer; and a magnetoelectric structure comprising a first electrically conductive layer, a magnetic film layer, a second electrically conductive layer, and recesses formed so as to create at least one electrically conductive coil around the magnetic film layer; with a portion of the substrate removed so as to enhance deformation of the piezoelectric layer. Also disclosed is a method of making the same. This inductor displays a tunable inductance range of >5:1 while consuming less than 0.5 mJ of power in the process of tuning, does not require continual current to maintain tuning, and does not require complex mechanical components such as actuators or switches.

A wireless power transmission system comprising a wireless transmitter capable of transmitting power and a wireless receiver capable of receiving power such that the transmitter or receiver comprises a controller and resonant tank, and the resonant tank comprises a capacitor and an electrically tunable inductor.

A current limiting device including a transformer including an element made from a magnetothermal material, a primary conductor, and a secondary winding. Heat is generated by the current flowing through the primary conductor and when the current exceeds a certain threshold it modifies the coupling coefficient of the transformer, which makes it possible to limit the current in the primary conductor.

The invention relates to an inductor, and particularly to an inductor for a transmitter circuit. The invention also concerns a transmitter including said inductor, a proximity detection system employing such a transmitter, and a method of making said inductor. The inductor of the invention includes a core having non-uniform permeability and a conductor winding arranged around the core. When used in a transmitter circuit, this allows an induced electromagnetic field to propagate through the core in a more efficient manner than otherwise possible, so resulting in a higher dynamic field strength for a given resonant circuit drive.

An oxide ceramic expressed by the general formula Sr.sub.2-xBa.sub.xCo.sub.2-yMg.sub.yFe.sub.12-zAl.sub.zO.sub.22, where 0.7x1.3, 0<y0.8, and 0.8z1.2.

An assembly for varying inductance, the assembly comprising a stator configured to produce at least one pair of magnetically opposed poles, a line extending from one pole of the at least one pair of magnetic poles to a remaining pole of the at least one pair of poles defining a first direction, and a rotor adjacent to the stator. The rotor includes a rotor body formed from a first material having a first effective magnetic permeability, the rotor body defining a plurality of recesses extending parallel to a rotation axis of the rotor, the rotation axis extending along the first direction, and a plurality of bars formed from a second material and disposed within the plurality of recesses, the second material having a second effective magnetic permeability, a rotation of the rotor about the rotation axis causes a periodical alternation of inductance of the assembly.

An assembly for varying inductance, the assembly comprising a stator configured to produce at least one pair of magnetically opposed poles, a line extending from one pole of the at least one pair of magnetic poles to a remaining pole of the at least one pair of poles defining a first direction, and a rotor adjacent to the stator. The rotor includes a rotor body formed from a first material having a first effective magnetic permeability, the rotor body defining a plurality of recesses extending parallel to a rotation axis of the rotor, the rotation axis extending along the first direction, and a plurality of bars formed from a second material and disposed within the plurality of recesses, the second material having a second effective magnetic permeability, a rotation of the rotor about the rotation axis causes a periodical alternation of inductance of the assembly.

The invention generally relates to a field regulator, particularly a field regulator for a resonant circuit, a transmitter including such a field regulator, a proximity detection system including such a transmitter, and a method of regulating a resonant circuit. In one aspect the invention provides a field regulator for a resonant circuit, the resonant circuit including an inductor coil around a core, the field regulator including a DC bias circuit configured to apply a DC bias current to the inductor coil for regulating an electromagnetic field generated by the inductor. The DC bias circuit can be used to selectively change the inductance of the inductor in the resonant circuit so as to maintain a consistent field strength in a changing environment, particularly to take into account the presence of large metal bodies which might otherwise adversely impact on operation. In particular, the DC bias current may be used to selectively change the natural frequency of the resonant circuit so as to shift the resonant circuit towards a desired resonance point.

A method and apparatus for managing a magnetic permeability of a core. The apparatus comprises a core and a plurality of electrodes positioned relative to the core. The core comprises a plurality of liquid crystals and a plurality of magnetic nanoparticles. Changing a voltage applied to the plurality of electrodes changes a magnetic permeability of the core.