Phantom geometry and tissue-simulant liquids

Indexsar's products for testing emf

I’m investigating the visualisation of electromagnetic fields, part of our exploratory process to look at the materiality of RFID. What are we talking about when we say ‘touch-based interaction’ or ‘near field’ for instance? This investigation threw up an interesting company: Indexsar specialises in:

“Turnkey test systems for the measurement of SAR (Specific Absorption Rate) and the Over The Air (OTE) testing of wireless devices. Our product range includes E-field probes for use in both air and in tissue-simulant liquids, equipment for accurate testing of the dielectric properties of phantom liquids and a system to give a 3-Dimensional presentation of mobile handset radiation and sensitivity. We can supply suitable RF amplifiers and directional couplers for wireless product testing and can offer suitable phantoms (heads, hands and liquids) for testing radiated emissions.”

Their test setup includes 6-axis industrial robots to move sensors around models of human anatomy (or “phantom geometry” in official testing language). Their setups include geometry for the head, and the right hand (no left hands yet). In the test rig below a liquid model moves while the sensors are stationary. It looks like it has been hacked together from meccano and a Wacom pad.

Indexsar's test setup for testing emf

These are some visualisations of bodily electromagnetic fields from Flomerics MicroStripes and Hugo:

Visualisations of EMF in anatomical models

Microstripes software is a 3D electromagnetic simulation & synthesis tool:

“MicroStripes is widely used to design antenna and microwave structures and assess their installed performance, to optimize RFID systems, to analyze radar cross-section (RCS), EMI/EMP and lightning effects on vehicles, ships and aircraft, and to predict absorption of EM fields in human tissue.”

Another visualisation:

Visualisation using Flometrics MicroStripes.

Leafing through the manual for my Nokia E60 I noticed that it includes guidelines on holding the phone, in order not to degrade the performance, and thus battery life of the antennae.

Nokia E60 manual

As we move towards multiradio devices, this analysis is going to become more important. I wonder what the fields look like around the RFID/NFC phones like the 3220...

Related things:

  1. Fields and seams This is a design brief, one of many themes that the Touch project is investigating. “Don’t place your bank cards, hard disks, etc. here”. With increasingly ubiquitous wireless networks the physical world is becoming......
  2. Making radio tangible Next week we’re launching some new work that explores the spatial aspects of RFID. So before we publish that, here is a quick summary of existing work on radio, sensors and space that I’ve......
  3. Touchable services: Art Server In March 2006 Fourth year interaction design students at AHO conducted intense one-week investigations into Near Field Communication in a project called Touchable services. See more student projects. Anna Daniell, Castilnano Simoons, Stig Skjelvik......

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  1. Posted 31 August 2006 at 14:29 | Permalink

    Nick Knouf’s aetherspace is a rather fanciful, arty “visualisation” of electromagnetic fields, but you may find it interesting anyway:
    Won an honourable mention at Ars Electronica.

  2. Timo
    Posted 31 August 2006 at 14:33 | Permalink

    Nice, thanks Michelle. I’m writing another post about EMF visualisation products and projects, I’ll add that to it.

2 Trackbacks

  1. By Fields and seams · Touch on 2 July 2007 at 23:31

    [...] Phantom geometry and tissue-simulant liquids. “Investigating the visualisation of electromagnetic fields.” [...]

  2. By Making radio tangible on 10 October 2009 at 13:45

    [...] antenna measurement is a difficult task, if not almost a ‘black art’. Using specialist robotic equipment and slowly measuring the intensity of radio signals at various points in space, it is possible to [...]

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