Energy deposition in biological tissue near portable radio transmitters at VHF and UHF

This paper presents the results of measurements of temperature increase, due to RF energy deposition, in simulated biological tissue near 6 W portable transmitters with helical and whip antennas. At close distances (< .5´´) VHF helices deposit energy in the surface fatty layers, with practically no penetration into muscle tissue; 450 MHz helical antennas transfer energy mostly into the surface fat, with the penetration into deep tissue increasing by a factor of 10 from 150 MHz. UHF quarter-wavelength whips deposit power mostly in the muscle tissue. At larger distances (> 2´´), the detected temperature increases are extremely small, indicating that portable radios are safe.