Electromagnetic near-field scanner

Electromagnetic near-field scanner

Electromagnetic near-field scanner could be defined as a measurement system to determine a spatial distribution of an electrical quantity provided by a single or multiple field probes acquired in the near-field region of a device under test possibly accompanied by the associated numerical post-processing methods enabling a conversion of the measured quantity into electromagnetic field.

Depending on a signal receiver detecting the probe signal, voltage as a function of time or frequency is a typical measured quantity. It should be underlined that as the DUT may be considered any object "radiating or storing" electromagnetic field energy intentionally or unintentionally, e.g. the antenna radiation excited beyond its resonance frequency. The voltage pattern is usually mapped on planar, cylindrical or spherical geometrical surfaces as a collection of a finite number of spatial samples.

Antenna near-field scanner

First scanners were built in the 1950s to map probe signal variations in front of microwave antennas. Determination of a far-field radiation pattern constitutes the primary application of antenna near-field scanners. This novel technique offered an attractive alternative to conventional open area test sites for measurements of high gain, electrically large antennas or antenna arrays (gain > 20 dBi, diameter > 5λ) in an indoor, controlled and all-weather capability environment. Among well recognized and analyzed errors of the near-field measurements, multiple reflections between an antenna under test (AUT) and an electromagnetically non-transparent field detection system (scatterer) belong to the most contributing errors when the AUT has a high gain. Therefore, the scanning surface is recommended to be located "outside the reactive near-field region" of the AUT.

EMI near-field scanner

In EMI applications, the main focus of a scanner system is on localization of real electromagnetic interference (EMI) sources distributed in a DUT. Accordingly, the scanning surface is located "in the highly reactive region" of the DUT to enable a relative spatial localization of the electric charges and current surface densities directly from the mapped pattern of probe signals. Typically the separation between the scanning surface and the DUT is much smaller as the largest geometrical dimension of the DUT. Exemplarydistances are 1 mm for scanning of PCBs and 30 μm for scanning of integrated circuits on a die level. In order to quickly localize field emission in frequency domain, time domain detection techniques together with signal processing based on fast Fourier transform could be employed, e.g. utilizing a digital storage oscilloscope as a signal receiver.

Further reading

cite book
title = IEC/TS 61967-3: Integrated circuits - Measurement of electromagnetic emissions, 150 kHz to 1 GHz - Part 3: Measurement of radiated emissions - Surface scan method
publisher = International Electrotechnical Commission
date = June 2005
url = www.iec.ch

cite book
last = Slater
first = Dan
title = Near-Field Antenna Measurements
publisher = Artech House, Inc.
date = 1991
location = Norwood, MA, USA

cite book
last = Tankielun
first = Adam
title = Data Post-Processing and Hardware Architecture of Electromagnetic Near-Field Scanner
publisher = Shaker Verlag
date = 2008
location = Aachen, Germany

cite journal
last = Yaghjian
first = Arthur D.
title = An Overview of Near-Field Antenna Measurements
journal = IEEE Transactions on Antennas and Propagation
volume = AP-34
issue = 1
pages = 30–45
date = January 1986


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Near-field scanner — Electromagnetic near field scanner could be defined as a measurement system to determine a spatial distribution of an electrical quantity provided by a single or multiple field probes acquired in the near field region of a device under test… …   Wikipedia

  • Near and far field — This article is about the electromagnetic concept. For the mathematical, see Near field (mathematics). Antenna field regions for antennas that are shorter than the wavelength of the radiation they emit, such as the whip antenna of a citizen s… …   Wikipedia

  • Radiation pattern — Three dimensional antenna radiation patterns. The radial distance from the origin in any direction represents the strength of radiation emitted in that direction. The top shows the directive pattern of a horn antenna, the bottom shows the… …   Wikipedia

  • Radio-frequency identification — (RFID) is a technology that uses radio waves to transfer data from an electronic tag, called RFID tag or label, attached to an object, through a reader for the purpose of identifying and tracking the object. Some RFID tags can be read from… …   Wikipedia

  • List of electronics topics — Alphabetization has been neglected in some parts of this article (the b section in particular). You can help by editing it. This is a list of communications, computers, electronic circuits, fiberoptics, microelectronics, medical electronics,… …   Wikipedia

  • Real-time locating — Articleissues confusing=July 2008 refimprove=May 2008 essay=May 2008: This page specifically concerns operational aspects of RTLS. For methodology issues see locating engine. For technology issues see wireless. According to ISO/IEC JTC1 SC31 and… …   Wikipedia

  • Stochastic cooling — is a form of particle beam cooling. It is used in some particle accelerators and storage rings to control the emittance of the particle beams in the machine. This process uses the electrical signals that the individual charged particles generate… …   Wikipedia

  • Magnetic resonance imaging — MRI redirects here. For other meanings of MRI or Mri, see MRI (disambiguation). Magnetic resonance imaging Intervention Sagittal MR image of the knee ICD 10 PCS B?3?ZZZ …   Wikipedia

  • Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics       Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity.       Computer scientist Manindra Agrawal of the… …   Universalium

  • Optics — For the book by Sir Isaac Newton, see Opticks. Optical redirects here. For the musical artist, see Optical (artist). Optics includes study of dispersion of light. Optics is the branch of …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”