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Improved Characterization and Monitoring of Electromagnetic Sources

Lawrence Livermore National Laboratory

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Technology Marketing Summary

LLNL's technology is useful in fields such as power systems engineering, security monitoring, and vehicle tracking to identify, locate and monitor a particular source of electromagnetic radiation in a noisy broadband environment.  Conventional broadband filtering techniques are often inefficient in reducing unwanted electromagnetic noise, and this inefficiency results in higher energy and processing costs along with imprecise location, monitoring and tracking capabilities.  The invention described here creates a method for identifying the bearing and/or location of noise sources by exploiting a novel Poynting-vector filtering method. Once the Poynting vector has been identified, the source of the signal can be readily located.


Innovative research at Lawrence Livermore National Laboratory (LLNL) has developed a novel filtering technology for determining the frequency components associated with a particular bearing and/or location of a source emitting the electromagnetic noise for which a Poynting vector can be defined. The frequency components related to that specific source can be isolated from the other components of the power spectrum, and their Poynting vectors can be used to characterize the source.  

By grouping the undesired frequency components according to the characteristics of their observed Poynting vectors, a common source can be identified. This is a significant improvement over conventional methods that require the input of detailed information about the location, bearing, or source characteristics. Experimental results and numerical simulations have established the validity of this technique.

Alternatively, this method may be used to isolate the Poynting vector for the signal of interest so that extraneous signals can be identified and eliminated from the broadband spectrum.  Broadband frequency components thus isolated can be tagged as not associated with the signal of interest. 
  • Poynting-vector filtering is a diagnostic tool far superior to the current trial-and-error methods conventionally applied to electromagnetic radiation source identification.
  • Sources of broadband noise, such as alternating-current (AC) generators and loads, transmission lines, transformers, and radio-frequency transmitters, can be more readily identified, characterized and monitored, or tagged for elimination.
  • This method provides a multi-use apparatus for detecting and locating one or multiple sources emitting electrical and magnetic field components.
  • LLNL Poynting-vector filtering is applicable to moving and stationary radiating sources.
  • The LLNL Poynting-vector filter technology can be applied to the development sensors and sensor networks for identification/monitoring of electromagnetic radiation sources.
Applications and Industries
  • Power transmission and distribution network operators can identify and monitor transmission losses in power grid subsystems and components such as AC generators, transformers.  
  • Power systems engineers can conduct time-based assessment and mapping of power usage.
  • Spatial mapping technologies can better identify and tag noise sources and their associated temporal assessments.
  • National security applications may include the protection of transportation and shipping systems currently vulnerable to disruption by means of introduced broadband noise or other invasive electromagnetic-spectrum technologies.
  • Military uses may include missile guidance improvement, communications security enhancements, and more precise GPS information.
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 7,440,858
Poynting-vector based method for determining the bearing and location of electromagnetic sources
A method and apparatus is utilized to determine the bearing and/or location of sources, such as, alternating current (A.C.) generators and loads, power lines, transformers and/or radio-frequency (RF) transmitters, emitting electromagnetic-wave energy for which a Poynting-Vector can be defined. When both a source and field sensors (electric and magnetic) are static, a bearing to the electromagnetic source can be obtained. If a single set of electric (E) and magnetic (B) sensors are in motion, multiple measurements permit location of the source. The method can be extended to networks of sensors allowing determination of the location of both stationary and moving sources.
Lawrence Livermore National Laboratory 10/21/2008
Patent 7,991,570
Poynting-vector filter
A determination is made of frequency components associated with a particular bearing or location resulting from sources emitting electromagnetic-wave energy for which a Poynting-Vector can be defined. The broadband frequency components associated with a specific direction or location of interest are isolated from other components in the power spectrum that are not associated with the direction or location of interest. The collection of pointing vectors can be used to characterize the source.
Lawrence Livermore National Laboratory 08/02/2011
Technology Status
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