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A COMPARISON BETWEEN THE ENERGY DEPOSITION IN PORTABLE RADIO OPERATORS AT 900 MHz AND 450 MHz

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Q. BALZANO, O. GARAY, F.R. STEEL · 1978

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Higher frequency radio waves concentrate more energy in tissue and focus deeper into the brain due to head shape.

Plain English Summary

Summary written for general audiences

This 1978 study compared how electromagnetic energy from portable radios deposits in human tissue at two frequencies: 450 MHz and 800-900 MHz. Researchers found that higher frequencies (800-900 MHz) concentrate more energy in surface tissue layers, while the shape of the human head creates a focusing effect that drives energy deeper into brain tissue at these higher frequencies.

Why This Matters

This early research revealed a critical principle that remains relevant today: higher frequencies don't just penetrate differently, they can actually focus more intensely in specific areas of your body. The finding that 800-900 MHz signals focus energy deeper into simulated brain tissue due to head geometry is particularly significant because this frequency range closely matches modern cellular networks. What makes this study especially important is that it demonstrated how the human body's shape itself can amplify EMF exposure in unexpected ways. While this research used portable radios, the physics principles apply directly to today's smartphones, which operate in similar frequency ranges and are held against your head during calls.

Exposure Information

Specific exposure levels were not quantified in this study.

Cite This Study
Q. BALZANO, O. GARAY, F.R. STEEL (1978). A COMPARISON BETWEEN THE ENERGY DEPOSITION IN PORTABLE RADIO OPERATORS AT 900 MHz AND 450 MHz.
Show BibTeX
@article{a_comparison_between_the_energy_deposition_in_portable_radio_operators_at_900_mh_g4554,
  author = {Q. BALZANO and O. GARAY and F.R. STEEL},
  title = {A COMPARISON BETWEEN THE ENERGY DEPOSITION IN PORTABLE RADIO OPERATORS AT 900 MHz AND 450 MHz},
  year = {1978},
  
  
}

Quick Questions About This Study

Higher frequencies like 800-900 MHz tend to be absorbed in the superficial layers of tissue, creating higher power density deposition (mW/cm³) for the same power flow, concentrating energy rather than distributing it throughout the body.
The study found that the frontal surfaces of the human head create a slight focusing effect for 800-900 MHz frequencies, concentrating RF energy and causing deeper penetration into simulated brain tissue than occurs at lower frequencies.
Researchers used a sleeve dipole antenna with the 800-900 MHz radio, which was approximately the same size as the resonant whip antenna used with 450 MHz portable transmitters for direct comparison.
No, the focusing of RF energy by head shape was only detected at 800-900 MHz frequencies. This focusing effect was not observed at the lower 450 MHz frequency during the measurements.
Researchers used phantoms with human features and flat slabs of biological tissue to measure power deposition patterns, comparing mechanisms of electromagnetic energy absorption between the two different frequency ranges.