2
Electromagnetic Fields in Biological Systems
1.11 Radiofrequency Dosimetry and Energy
Absorption in Anatomical Models ...................... 25
Coupling from Handheld Mobile
Phones • Specific Absorption Rate in Childlike
Head Models • Fields from Body-Worn
Devices • Whole-Body Exposure from Cell-Phone
Base Stations • Summary of Radiofrequency Field
Coupling
1.12 Coupling of Short and Ultra-Wideband
Pulses into the Human Body ................................40
Induced Electromagnetic Pulse Fields in Biological
Bodies • Gaussian Electromagnetic Pulse
Inside a Planar Biological Medium • Gaussian
Electromagnetic Pulse inside Spherical Head
Models • Constant Conductivity Spherical Model
for Electromagnetic Pulse Propagation • Induced
Ultra-Wideband Field and Current • Summary of
Short and Ultra-Wideband Pulse Coupling
1.13 Coupling of Millimeter and Terahertz Waves ... 59
Transmitted and Reflected Millimeter
Waves and Terahertz Fields, and Energy
Deposition • Summary of Millimeter-Wave
Coupling
References ............................................................................ 63
1.1 Introduction
Electromagnetic fields or energies of frequencies that range from 0 Hz to 1 THz (1 THz =
10 12 Hz) have wavelengths longer than 1 μm in air. Furthermore, at wavelengths close
to the micrometer limit of the spectrum, electromagnetic energy behaves as infrared
radiation. These wavelengths produce photons (or quanta) of low energy; therefore,
under ordinary circumstances, the energy in a photon is too low to break chemical
bonds, excite electrons, or produce ionization of biological molecules. Consequently,
they are often referred to as low-energy or nonionizing radiation. Electromagnetic energies propagate through a material medium (including biological medium) at a constant
speed in that medium. For example, they propagate through air or vacuum at the speed
of light, that is, at 2.998 × 10 8 m/s. Moreover, electromagnetic energies with wavelengths
longer than 10 m (frequencies lower than 30 MHz) have interaction properties that differ
greatly from those of wavelengths that are approximately equal to or less than the physical dimensions of a human body.
Although living organisms thrive in a natural electromagnetic environment, they are
increasingly subjected to a myriad of human-made nonionizing radiation in the form
of electromagnetic fields and waves for telecommunication uses, industrial and medical applications, and many other purposes. For example, the radiofrequency (RF) band
of 300–30,000 kHz (or 0.3–30 MHz with wavelengths from 1000 m to 10 m) is used in
medicine for ablating, coagulating, and cauterizing tissue. Recently, nanosecond-pulsed
electric fields were shown to induce long-lasting plasma membrane permeabilization
changes. They are providing new insights into the nature of pulsed electric field induced
Electromagnetic Fields in Biological Systems
1.11 Radiofrequency Dosimetry and Energy
Absorption in Anatomical Models ...................... 25
Coupling from Handheld Mobile
Phones • Specific Absorption Rate in Childlike
Head Models • Fields from Body-Worn
Devices • Whole-Body Exposure from Cell-Phone
Base Stations • Summary of Radiofrequency Field
Coupling
1.12 Coupling of Short and Ultra-Wideband
Pulses into the Human Body ................................40
Induced Electromagnetic Pulse Fields in Biological
Bodies • Gaussian Electromagnetic Pulse
Inside a Planar Biological Medium • Gaussian
Electromagnetic Pulse inside Spherical Head
Models • Constant Conductivity Spherical Model
for Electromagnetic Pulse Propagation • Induced
Ultra-Wideband Field and Current • Summary of
Short and Ultra-Wideband Pulse Coupling
1.13 Coupling of Millimeter and Terahertz Waves ... 59
Transmitted and Reflected Millimeter
Waves and Terahertz Fields, and Energy
Deposition • Summary of Millimeter-Wave
Coupling
References ............................................................................ 63
1.1 Introduction
Electromagnetic fields or energies of frequencies that range from 0 Hz to 1 THz (1 THz =
10 12 Hz) have wavelengths longer than 1 μm in air. Furthermore, at wavelengths close
to the micrometer limit of the spectrum, electromagnetic energy behaves as infrared
radiation. These wavelengths produce photons (or quanta) of low energy; therefore,
under ordinary circumstances, the energy in a photon is too low to break chemical
bonds, excite electrons, or produce ionization of biological molecules. Consequently,
they are often referred to as low-energy or nonionizing radiation. Electromagnetic energies propagate through a material medium (including biological medium) at a constant
speed in that medium. For example, they propagate through air or vacuum at the speed
of light, that is, at 2.998 × 10 8 m/s. Moreover, electromagnetic energies with wavelengths
longer than 10 m (frequencies lower than 30 MHz) have interaction properties that differ
greatly from those of wavelengths that are approximately equal to or less than the physical dimensions of a human body.
Although living organisms thrive in a natural electromagnetic environment, they are
increasingly subjected to a myriad of human-made nonionizing radiation in the form
of electromagnetic fields and waves for telecommunication uses, industrial and medical applications, and many other purposes. For example, the radiofrequency (RF) band
of 300–30,000 kHz (or 0.3–30 MHz with wavelengths from 1000 m to 10 m) is used in
medicine for ablating, coagulating, and cauterizing tissue. Recently, nanosecond-pulsed
electric fields were shown to induce long-lasting plasma membrane permeabilization
changes. They are providing new insights into the nature of pulsed electric field induced