Johns Hopkins University

Dennis K Wickenden

Robert B Givens

Robert Osiander

Thomas J Kistenmacher

John C Murphy

John L Champion

Gabriel M Rebeiz

Scott A Ecelberger

Daniel G Jablonski

James H Higbie

William P D'Amico

Margaret Ann Darrin

Scott T Radcliffe

Douglas A Oursler

Eli A Richards

Richard T Cusick

Robert F Walsh

Provided herein is a xylophone bar magnetometer (XBM) with automatic resonance control, the XBM having a voltage input, a current drive input and a sensor output, having a voltage input switch for switching between a positive drive voltage and a negative drive voltage; a voltage controlled oscillator (VCO) for controlling the voltage input switch; and a feedback loop, connected between the sensor output and a input of the VCO.

Complementary metal-oxide semiconductor xylophone bar magnetometer with automatic resonance control

A Lorentz force assisted microelectromechanical switch is provided which is configured to have a capacitive switch and an electrical conductor placed in transversely extending electric and magnetic fields to generate the Lorentz force sufficient to operate the capacitive switch.

Lorentz force assisted switch

A Lorentz force-driven mechanical resonator apparatus that utilizes a high-Q resonant structure as both a mixing device and a high-Q bandpass filter. Specifically, an external time varying, but quasistatic, magnetic field is applied to the resonating device while simultaneously running a time varying electrical current through the device. The resulting Lorentz force (I&times;B) is proportional to the vector product of the electrical current in the bar (I) and the external magnetic field (B). Integrating such a resonant device with a magnetic field coil produces the functionality of an ideal radio frequency (RF) mixer coupled with a high-Q intermediate frequency (IF) filter. Wide tunability provides the capability to scan, or even step, an array of filters having very narrow bandwidths via a common local oscillator to a desired frequency range.

Lorentz force driven mechanical filter/mixer designs for RF applications

A sensor array system for detecting the position of an object or energy source. The system includes a plurality of sensors, each sensor having a limited field of view and being capable of detecting an object or energy source that is positioned within its field of view. The fields of view of at least some of the sensors overlap the fields of view of other sensors, and the overlapping fields of view define unique spatial regions. A data acquisition system is operatively connected to the plurality of sensors and is used to determine which sensors simultaneously detect an object or energy source, thereby determining the unique spatial region in which the object or energy source is located.

Sensor array system for object position detection

A microelectromechanical-based magnetostrictive magnetometer that uses, as an active element, a commercial (001) silicon microcantilever coated with an amorphous thin film of the giant magnetostrictive alloy Terfenol-D and a compact optical beam deflection transduction scheme. A set of Helmholtz coils is used to create an ac magnetic excitation field for driving the mechanical resonance of the coated microcantilever. When the coated microcantilever is placed in a dc magnetic field, the dc field will change the amplitude at the mechanical resonance of the coated microcantilever thereby causing a deflection that can be measured. The magnetometer has been demonstrated with a sensitivity near 1 .mu.T.

Microelectromechanical (MEMS)-based magnetostrictive magnetometer

The invention consists, in one embodiment, of a resonator such as a conductive bar supported by two wires placed at the nodal points of the fundamental resonance frequency. The wires also supply current of this frequency to the resonator. In the presence of a magnetic field, the Lorentz force causes the resonator to vibrate. The amplitude of this vibration is proportional to a vector component of the magnetic field. The motion of the resonator is detected using one of a number of possible methods including optical beam deflection. The invention has a sensitivity of at least 1 nT, comparable to that of a commercial fluxgate magnetometer, and a dynamic range exceeding 80 dB.

Lorentz force magnetometer having a resonator

Growing community of inventors

Woodbine, MD, United States of America

Dennis K Wickenden