Wireless power transmission (WPT) systems are provided. For example, the WPT system can use one or more power transmitting coils and a receiver for electromagnetically coupled wireless power transfer. The electrodynamic receiver can be in the form of an electrodynamic transducer where a magnet is allowed to oscillate near a receiving coil to induce a voltage in the receiving coil, a piezoelectric transducer where the magnet causes a vibrating structure with a piezoelectric layer to move, an electrostatic transducer where movement of the magnet causes a capacitor plate to move, or a combination thereof. An alternating magnetic field from the transmitting coil(s) excites the magnet in the receiver into mechanical resonance. The vibrating magnet then functions similar to an energy harvester to induce voltage/current on an internal coil, piezoelectric material, or variable capacitor. Embodiments utilize magnetic coupling and electromechanical resonance for safe, spatially distributed, low-frequency power delivery to portable devices.

A force sensor having a noise shielding layer is disclosed. For a first embodiment, a top noise shielding layer is configured on a top surface of a force sensor to screen noise signals which are caused by human body's touch or approaching from top of the force sensor. For a second embodiment, a bottom noise shielding layer is configured on a bottom surface of the force sensor to screen noise signals which are caused by human body's touch or approaching from bottom of the force sensor.

A force sensor having a noise shielding layer is disclosed. For a first embodiment, a top noise shielding layer is configured on a top surface of a force sensor to screen noise signals which are caused by human body's touch or approaching from top of the force sensor. For a second embodiment, a bottom noise shielding layer is configured on a bottom surface of the force sensor to screen noise signals which are caused by human body's touch or approaching from bottom of the force sensor.

A self-charging droplet capacitor for harvesting low-level ambient energy is provided. The capacitor includes a conductive liquid droplet, which is placed on a heterogeneous and hydrophobic surface of dielectric materials coated onto a conductive substrate. The substrate and the droplet, along with the dielectric materials in between, form a parallel-plate type capacitor. The droplet is free to move on the surface, and thus, provides a position-dependent variation of capacitance. The surface consists of two regions, each with a different material and thickness. The different strengths of solid-water contact electrification of the two materials give rise to a self-charging mechanism. The variation in thickness allows for the capacitance change required for energy harvesting.

A self-charging droplet capacitor for harvesting low-level ambient energy is provided. The capacitor includes a conductive liquid droplet, which is placed on a heterogeneous and hydrophobic surface of dielectric materials coated onto a conductive substrate. The substrate and the droplet, along with the dielectric materials in between, form a parallel-plate type capacitor. The droplet is free to move on the surface, and thus, provides a position-dependent variation of capacitance. The surface consists of two regions, each with a different material and thickness. The different strengths of solid-water contact electrification of the two materials give rise to a self-charging mechanism. The variation in thickness allows for the capacitance change required for energy harvesting.

An all-silicon electrode capacitive transducer comprising: a movable silicon microstructure coupled to a glass substrate, the movable silicon microstructure having a movable silicon electrode, the glass substrate having a top surface and at least one recess, the movable silicon electrode having a first flat surface parallel to a plane of the top surface of the glass substrate, the movable silicon electrode having a first electronic work function; and a stationary silicon electrode coupled to a glass substrate, the stationary silicon electrode located adjacent to the movable silicon electrode, the stationary silicon electrode configured to sense or actuate displacement of the movable silicon microstructure, wherein the stationary silicon electrode has a second flat surface parallel to the first flat surface, the stationary silicon electrode having a second electronic work function equal to the first electronic work function.

An all-silicon electrode capacitive transducer comprising: a movable silicon microstructure coupled to a glass substrate, the movable silicon microstructure having a movable silicon electrode, the glass substrate having a top surface and at least one recess, the movable silicon electrode having a first flat surface parallel to a plane of the top surface of the glass substrate, the movable silicon electrode having a first electronic work function; and a stationary silicon electrode coupled to a glass substrate, the stationary silicon electrode located adjacent to the movable silicon electrode, the stationary silicon electrode configured to sense or actuate displacement of the movable silicon microstructure, wherein the stationary silicon electrode has a second flat surface parallel to the first flat surface, the stationary silicon electrode having a second electronic work function equal to the first electronic work function.

Nano-electromechanical systems (NEMS) devices that utilize thin electrically conductive membranes, which can be, for example, graphene membranes. The membrane-based NEMS devices can be used as sensors, electrical relays, adjustable angle mirror devices, variable impedance devices, and devices performing other functions.

Nano-electromechanical systems (NEMS) devices that utilize thin electrically conductive membranes, which can be, for example, graphene membranes. The membrane-based NEMS devices can be used as sensors, electrical relays, adjustable angle mirror devices, variable impedance devices, and devices performing other functions.

A Static Electrostatic Generator (SEG) is disclosed which produces static charges at high voltage and low current. The SEG is capable of generating positive or negative charges on a metal sphere by reversing the polarity of a DC source. The conversion efficiency of the system is about 47% and its design is simple, lightweight, and easy to manufacture. The SEG is a static device and no mechanical movement is required to produce charges. Also, the design is easily scalable.