Radio frequency electromagnetic fields

Berry et al. [54] employed guidelines for skin exposure to THz radiation (15 GHz to 115 THz) drawn from American National Standard for the Safe Use of Lasers (ANSI Z136.1) and from the IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields (C95.1). They concluded that the maximum permissible average beam power was 3 mW, suggesting that typical THz imaging systems are safe. 

Institute of Electrical Mid Electronic gineers, American National Standard Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields. S kHz to 300 GHz, IKKF Piscataway, NJ, C95.1-1991 (1992). 

RFID is the wireless noncontact use of radio-frequency electromagnetic fields to transfer electronic data. The performance and the feasibility of inkjet printed dipole RFID tag antennas have been experimentally studied (4). 

R. Huber, J. Schruder, T. Graf, et al.. Radio frequency electromagnetic field exposure in humans estimation of SAR distribution in the brain, effects on sleep and heart rate, Bioelectromagnetics 24 (4) (2003) 262-276. 

Interestingly, in the December 2005 issne of the same periodical, Ralph Moss s column The War on Cancer, asks the qnestion, Do Radio Frequency Energy Fields Cause Cancer The qnestion pertains mostly to mobile phones. The American Cancer Society says no, bnt Moss offers some information to the contrary. In any event, there is the work of Rife and others nsing radio freqnency electromagnetic fields (RFEMFs) against cancer. 

Electromagnetic radiation consists of a stream of photons. Each photon is made up of an electric field component and a magnetic field component, and these two components are mutually perpendicular. The frequency of a photon determines how fast the electric field component and magnetic field component will pulse, or beat. Radio-frequency electromagnetic radiation at 500 MHz will thus have a magnetic field component that beats 500 million times a second, by definition. 

Another important ingredient for a magnetic resonance experiment is represented by the presence of the radio-frequency (rf) field. Only the magnetic component of the electromagnetic field, ie,. Bi(0=Siocos( 27tvt) interacts with the magnetic moment of the nuclei. The amplitude of the rf field is Bio and i is the carrier frequency. This field is produced by a rf coil and leads to a perturbation Hamiltonian... 

Near the outlet from the torch, at the end of the concentric tubes, a radio high-frequency coil produces a rapidly oscillating electromagnetic field in the flowing gas. The applied high-frequency field couples inductively with the electric fields of the electrons and ions in the plasma, hence the name inductively coupled plasma or ICP. 

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