skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Narrow field electromagnetic sensor system and method

Abstract

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor systemmore » also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.« less

Inventors:
Publication Date:
Research Org.:
University of California
OSTI Identifier:
403667
Patent Number(s):
US 5,576,627/A/
Application Number:
PAN: 8-405,644; TRN: 97:000142
Assignee:
Univ. of California, Oakland, CA (United States) PTO; SCA: 055001; 440800; PA: EDB-97:001287; SN: 96001695588
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Patent
Resource Relation:
Other Information: PBD: 19 Nov 1996
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; 44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; INTRUSION DETECTION SYSTEMS; DESIGN; RADIOWAVE RADIATION; RADIATION DETECTION; RADIATION MONITORS; USES; DATA PROCESSING; TIME-OF-FLIGHT METHOD; MEASURING METHODS

Citation Formats

McEwan, T.E.. Narrow field electromagnetic sensor system and method. United States: N. p., 1996. Web.
McEwan, T.E.. Narrow field electromagnetic sensor system and method. United States.
McEwan, T.E.. 1996. "Narrow field electromagnetic sensor system and method". United States. doi:.
@article{osti_403667,
title = {Narrow field electromagnetic sensor system and method},
author = {McEwan, T.E.},
abstractNote = {A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1996,
month =
}
  • A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling onlymore » the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.« less
  • This patent describes a sensor for use with a source of electromagnetic energy for indicating the presence of a low magnetic field with a sensitivity of at least 10{sup {minus} 10} tesla. It comprises: a sensing element consisting essentially of a high critical temperature superconductor ceramic oxide material without the need for further processing, said critical temperature being above 77{degrees}; means for cooling the sensing element to a temperature below the critical temperature of the superconductor material whereby the sensing element becomes superconducting; means for applying electromagnetic energy from the source to the sensing element whereby a first portion ofmore » the applied energy is absorbed by the sensing element; means for detecting the amount of the energy absorbed by the sensing element; and means modulating the sensing element for providing a reference signal for phase-sensitive detection and for biasing the electromagnetic energy absorption characteristics of the sensing element to a predetermined absorption reference value.« less
  • Microanalytical systems based on a microfluidics/electrochemical detection scheme are described. Individual modules, such as microfabricated piezoelectrically actuated pumps and a microelectrochemical cell were integrated onto portable platforms. This allowed rapid change-out and repair of individual components by incorporating "plug and play" concepts now standard in PC's. Different integration schemes were used for construction of the microanalytical systems based on microfluidics/electrochemical detection. In one scheme, all individual modules were integrated in the surface of the standard microfluidic platform based on a plug-and-play design. Microelectrochemical flow cell which integrated three electrodes based on a wall-jet design was fabricated on polymer substrate. Themore » microelectrochemical flow cell was then plugged directly into the microfluidic platform. Another integration scheme was based on a multilayer lamination method utilizing stacking modules with different functionality to achieve a compact microanalytical device. Application of the microanalytical system for detection of lead in, for example, river water and saliva samples using stripping voltammetry is described.« less
  • The present invention provides a system for detecting and analyzing at least one of an electric field and an electromagnetic field. The system includes a micro/nanomechanical oscillator which oscillates in the presence of at least one of the electric field and the electromagnetic field. The micro/nanomechanical oscillator includes a dense array of cantilevers mounted to a substrate. A charge localized on a tip of each cantilever interacts with and oscillates in the presence of the electric and/or electromagnetic field. The system further includes a subsystem for recording the movement of the cantilever to extract information from the electric and/or electromagneticmore » field. The system further includes a means of adjusting a stiffness of the cantilever to heterodyne tune an operating frequency of the system over a frequency range.« less
  • A micromechanical sensor and method for detecting electromagnetic radiation involve producing photoelectrons from a metal surface in contact with a semiconductor. The photoelectrons are extracted into the semiconductor, which causes photo-induced bending. The resulting bending is measured, and a signal corresponding to the measured bending is generated and processed. A plurality of individual micromechanical sensors can be arranged in a two-dimensional matrix for imaging applications.