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SAR / Device Absorption

Comparison of numerical and experimental methods for determination of SAR and radiation patterns of handheld wireless telephones.

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Gandhi OP, Lazzi G, Tinniswood A, Yu QS, · 1999

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Calculated and measured SAR values for handheld wireless telephones agreed within plus or minus 20% across a range of 0.13 to 5.41 W/kg.

Plain English Summary

Summary written for general audiences

Researchers compared numerical and experimental methods for determining SAR and radiation patterns of handheld wireless telephones at 835 and 1900 MHz. Peak 1-g SARs ranged from 0.13 to 5.41 W/kg, yet agreement between calculated and measured data was generally within plus or minus 20%. The study noted that for a maximum radiated power of 600 mW at 800/900 MHz, peak 1-g SARs can be higher than 1.6 W/kg unless antennas are carefully designed and placed further away from the head.

Why This Matters

The numerical approach used was the finite-difference time-domain (FDTD) method with an expanding grid, allowing finer resolution near the antenna and coarser resolution further away. This procedure led to a saving of computer memory needed for SAR calculations by a factor of over 20. Automated SAR and radiation pattern measurement systems were used to validate both the calculated 1-g SARs and radiation patterns for several telephones, including some research test samples using a variety of antennas.

Exposure Details

SAR
0.13 to 5.41, W/kg
Source/Device
835 and 1900 MHz

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 0.13 to 5.41, W/kgExtreme Concern - 0.1 W/kgFCC Limit - 1.6 W/kgEffects observed in the Extreme Concern range (Building Biology)FCC limit is 12 times higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 1.90 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 1.90 GHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Study Details

The aim of this study is to investigate Comparison of numerical and experimental methods for determination of SAR and radiation patterns of handheld wireless telephones.

we used the expanding grid formulation of the finite-difference time-domain (FDTD) method for finer-...

Even though widely different peak 1-g SARs were obtained, ranging from 0.13 to 5.41 W/kg, agreement ...

Cite This Study
Gandhi OP, Lazzi G, Tinniswood A, Yu QS, (1999). Comparison of numerical and experimental methods for determination of SAR and radiation patterns of handheld wireless telephones. Bioelectromagnetics Suppl 4:93-101, 1999.
Show BibTeX
@article{op_1999_comparison_of_numerical_and_986,
  author = {Gandhi OP and Lazzi G and Tinniswood A and Yu QS and},
  title = {Comparison of numerical and experimental methods for determination of SAR and radiation patterns of handheld wireless telephones.},
  year = {1999},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/10334718/},
}
PubMed: 10334718

Cited By (32 papers)

Quick Questions About This Study

Agreement between calculated and measured data was excellent and generally within plus or minus 20%.
Peak 1-g SARs ranged from 0.13 to 5.41 W/kg across the telephones tested.
Five telephones were tested at each of 835 and 1900 MHz.
For a maximum radiated power of 600 mW at 800/900 MHz, peak 1-g SARs can be higher than 1.6 W/kg unless antennas are carefully designed and placed further away from the head.
Researchers used the expanding grid formulation of the finite-difference time-domain (FDTD) method.