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SAR / Device Absorption

Analysis of mobile phone design features affecting radiofrequency power absorbed in a human head phantom.

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Kuehn S, Kelsh MA, Kuster N, Sheppard AR, Shum M. · 2013

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Cell phone design dramatically affects radiation absorption, with technology type varying exposure by up to 100-fold during actual use.

Plain English Summary

Summary written for general audiences

Researchers analyzed how different cell phone designs affect the amount of radiofrequency energy absorbed by the head during calls. They found that phone technology type made the biggest difference in energy absorption, with older AMPS phones creating the highest levels and GSM phones the lowest. Phone shape, antenna design, and how you hold the phone also mattered, but to a lesser degree.

Why This Matters

This research reveals something crucial that most phone users never consider: the design of your phone significantly determines how much radiofrequency energy your head absorbs during calls. The science demonstrates that SAR levels can vary by a factor of 100 between different phone technologies, with real-world usage patterns creating even more dramatic differences. What this means for you is that not all phones expose you to the same levels of RF radiation. The finding that external antennas produce higher SAR levels than internal ones, and that holding your phone slightly away from your head reduces absorption, provides actionable information for reducing your exposure. While this study focused on technical measurements rather than health outcomes, it underscores how device engineering choices directly impact human RF exposure levels.

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 850 MHz - 1.90 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 850 MHz - 1.90 GHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study. The study examined exposure from: 850 MHz and 1900 MHz

Study Details

These test data, measured in phantoms with mobile phones operating at maximum antenna input power, permitted us to evaluate the variation in SARs across mobile phone design factors such as shape and antenna design, communication technology, and test date (over a 7-year period).

Descriptive statistical summaries calculated for 850 MHz and 1900 MHz phones and ANOVA were used to ...

Service technology accounted for the greatest variability in compliance test SARs that ranged from A...

Cite This Study
Kuehn S, Kelsh MA, Kuster N, Sheppard AR, Shum M. (2013). Analysis of mobile phone design features affecting radiofrequency power absorbed in a human head phantom. Bioelectromagnetics. 2013 Mar 26. doi: 10.1002/bem.21784.
Show BibTeX
@article{s_2013_analysis_of_mobile_phone_2313,
  author = {Kuehn S and Kelsh MA and Kuster N and Sheppard AR and Shum M.},
  title = {Analysis of mobile phone design features affecting radiofrequency power absorbed in a human head phantom.},
  year = {2013},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/23533135/},
}
PubMed: 23533135

Cited By (12 papers)

Quick Questions About This Study

Yes, different cell phones absorb vastly different amounts of radiofrequency energy. A 2013 study found that phone technology type creates the biggest difference, with older AMPS phones producing the highest absorption levels and GSM phones the lowest. Phone design and antenna type also matter but have smaller effects.
GSM cell phones have the lowest radiation absorption levels according to research analyzing different phone technologies. The study found radiation absorption ranked from highest to lowest: AMPS, CDMA, iDEN, TDMA, and GSM phones. However, GSM phones can actually have higher average power output during use than CDMA phones.
Yes, antenna type significantly affects radiation exposure to your head. Research shows external antennas produce greater radiation absorption than internal ones. However, the phone's technology type (like GSM vs CDMA) creates much larger differences in exposure levels than antenna design alone.
Yes, cell phone radiation absorption is significantly higher when the phone touches your head compared to holding it at a slight angle. A 2013 study found that tilting the phone away from your head reduces radiation absorption, while direct contact creates the highest exposure levels.
Traditional flip phones and brick-style phones actually produce higher radiation absorption than slide phones, according to research on phone design features. However, the phone's underlying technology (GSM, CDMA, etc.) makes a much bigger difference in radiation levels than the physical shape or style.