Abstract: Disclosed herein are systems and methods for wirelessly transmitting power to receivers that are freely mobile, such as power receivers for sensors attached to animal experiments. An example transmitter includes a resonator including a generator and transmitter coil, an initial drive signal generator that removes the generator from an ‘off’ state thereby causing the transmitter coil to create an alternating magnetic field that oscillates within a threshold of a resonant frequency of the generator, a phase detector that receives a signal from a receiver coil receiving power via the magnetic field, and a transition module that switches from the initial drive signal to a drive signal generated based on output from the phase detector. An example wireless power receiver has three turns of wire, one on each axis, around a ferrite plate, the outputs of which are connected in parallel to produce a combined output power signal.

Abstract: Apparatus and method for harvesting energy from the environment and/or other external sources and converting it to useful electrical energy. The harvester does not contain a permanent magnet or other local field source but instead relies on the earth's magnetic field of another source of a magnetic field that is external to the sensing device. One advantage of these new harvesters is that they can be made smaller and lighter than energy harvesters that contain a magnet and/or an inertial mass.

Abstract: Apparatus and method for harvesting energy from the environment and/or other external sources and converting it to useful electrical energy. The harvester does not contain a permanent magnet or other local field source but instead relies on the earth's magnetic field of another source of a magnetic field that is external to the sensing device. One advantage of these new harvesters is that they can be made smaller and lighter than energy harvesters that contain a magnet and/or an inertial mass.

Abstract: Apparatus and method for harvesting energy from the environment and/or other external sources and converting it to useful electrical energy. The harvester does not contain a permanent magnet or other local field source but instead relies on the earth's magnetic field of another source of a magnetic field that is external to the sensing device. One advantage of these new harvesters is that they can be made smaller and lighter than energy harvesters that contain a magnet and/or an inertial mass.

Abstract: Apparatus and method for wireless near-field magnetic communication (NFMC) of information (e.g., voice or data) over modest distances (centimeters to a few kilometers). The transmission can proceed from an inductive coil transmitter to a magneto-electric (ME) receiving device, or between two ME devices. Electrical power may also be transmitted from and/or received using the same device. In one case, power and data are transmitted from an induction coil to a distant ME device that collects power and transmits data back to the power-transmission coil. In another case, the wireless transfer of data can be carried out between two ME devices. ME devices can be engineered to transmit or receive data and to receive electric power over a variety of frequencies by changing their dimensions, their material makeup and configuration, electrode configurations, and/or their resonance modes (longitudinal, transversal, bending, shear etc).

Abstract: An inductive energy harvester comprises a permanent magnet magnetic field source attached by a pair of compact spiral disk springs to an induction coil. The springs position the magnet so that the induction coil surrounds one end of the magnet where the flux density is greatest. In addition, the magnetic flux emerging from that end of the magnet is enhanced by a disk of magnetic material having high permeability and high flux density. In another embodiment, the magnetic field source comprises two dipole magnets arranged in opposing flux relationship with a thin layer of high flux density, high magnetic permeability material located in a gap between the magnets.

Abstract: Small implantable magnetostrictive-electroactive (ME) device for delivering electrical energy to surrounding tissue. The wireless ME device is activated by a changing magnetic field from an externally applied alternating magnetic field source. The ME device provides a means for stimulating a nerve, tissue or internal organ with direct electrical current, such as relatively low-level direct current for temporary or as needed therapy. The field source (e.g. small coil antenna) may be a hand-held device or affixed to the wearer's skin, clothing or accessories. The ME implant may be configured as pellets which are small enough to be implanted through a surgical needle. In one embodiment, the wireless energy transmission system can be used for stimulating bone growth.

Abstract: A magnetic field sensor comprises one or more magnetic layers of magnetostrictive material that is mechanically bonded to one or more layers of electroactive material. When a magnetic field is applied to the device, it rotates the magnetization that is present in the in the magnetostrictive material thereby generating a magnetostrictive stress in the material. The magnetostrictive stress generated by this layer, in turn, stresses the piezoelectric layer to which the magnetostrictive layer is bonded. In order to increase sensitivity, the voltage across the piezoelectric material is measured in a direction that is parallel to the plane in which the magnetization in the magnetic material rotates.

Abstract: Apparatus and method for harvesting energy from the environment and/or other external sources and converting it to useful electrical energy. The harvester does not contain a permanent magnet or other local field source but instead relies on the earth's magnetic field of another source of a magnetic field that is external to the sensing device. One advantage of these new harvesters is that they can be made smaller and lighter than energy harvesters that contain a magnet and/or an inertial mass. A small implantable stimulator(s) includes at least one passive magnetostrictive/electro-active (PME) magnetic-field sensor for delivering electrical stimulation to surrounding tissue. The PME is charged utilizing a changing magnetic field from an external alternating magnetic field source at a frequency particular to the PME. The small stimulator provides means of stimulating a nerve, tissue or internal organ with direct electrical current, such as relatively low-level direct current for temporary or as needed therapy.

Abstract: In a vibrational energy harvester, an external vibration causes relative motion between a permanent magnet and a magnetic field sensing element composed of a magnetostrictive material bonded to an electroactive material. The changing magnetic field causes a rotation of magnetization in the magnetostrictive material and the rotating magnetization generates a stress in the magnetostrictive material. The stress is transmitted to the electroactive material, which responds by generating electrical power.