Absorption of Millimeter Waves by Human Beings and its Biological Implications

Gandhi, O.P.; Riazi, Abbas

doi:10.1109/tmtt.1986.1133316

Cited by 192 publications

(127 citation statements)

References 15 publications

Supporting

Mentioning

117

Contrasting

Unclassified

Order By: Relevance

“…Among these applications, let us mention: SAR distribution and the microwave power coupling in hyperthermia [35], the electromagnetic absorption due to the presence of clothing (for instance [36]), the microwave coupling in medical imaging system [37] and SAR reduction from an undesired external source [38]. According to the application, the external insulator is called clothing, bolus, matching layer or shield.…”

Section: External Insulation: Numerical Resultsmentioning

confidence: 99%

The Effect of Insulating Layers on the Performance of Implanted Antennas

Merli

Fuchs

Mosig

et al. 2011

IEEE Trans. Antennas Propagat.

118

View full text Add to dashboard Cite

Abstract-This work presents the analysis of the influence of insulation on implanted antennas for biotelemetry applications in the Medical Device Radiocommunications Service band. Our goal is finding the insulation properties that facilitate power transmission, thus enhancing the communication between the implanted antenna and an external receiver. For this purpose, it has been found that a simplified model of human tissues based on spherical geometries excited by ideal sources (electric dipole, magnetic dipole and Huygens source) provides reasonable accuracy while remaining very tractable due to its analytical formulation. Our results show that a proper choice of the biocompatible internal insulation material can improve the radiation efficiency of the implanted antenna (up to six times for the investigated cases). External insulation facilitates the electromagnetic transition from the biological tissue to the outer free space, reducing the power absorbed by the human body. Summarizing, this work gives insights on the enhancement of power transmission, obtained with the use of both internal, biocompatible and external, flexible insulations. Therefore, it provides useful information for the design of implanted antennas.

show abstract

Section: External Insulation: Numerical Resultsmentioning

confidence: 99%

The Effect of Insulating Layers on the Performance of Implanted Antennas

Merli

Fuchs

Mosig

et al. 2011

IEEE Trans. Antennas Propagat.

118

View full text Add to dashboard Cite

show abstract

“…In contrast to these results, one laboratory has reported responses from cochlear nucleus units with characteristic frequencies in the normal range of hearing for the cat that were inconsistent with head resonance having a primary role in RF hearing [Seaman and Lebovitz, 1987]. Gandhi and Riazi [1986] calculated RF hearing thresholds at 30-300 GHz, but there is little if any physiological significance of these calculations to RF hearing because: (a) their calculated fundamental frequencies in the head are of the order of several hundred kilohertz, well above the maximum acoustic frequency of about 20 kHz for human hearing, and (b) there are no reports of human perception of RF pulses at frequencies higher than 10 GHz (see Table 1). …”

Section: Similarity Of Auditory Response To Rf Energy and Conventionamentioning

confidence: 89%

Auditory response to pulsed radiofrequency energy

Elder

Chou

2003

Bioelectromagnetics

View full text Add to dashboard Cite

The human auditory response to pulses of radiofrequency (RF) energy, commonly called RF hearing, is a well established phenomenon. RF induced sounds can be characterized as low intensity sounds because, in general, a quiet environment is required for the auditory response. The sound is similar to other common sounds such as a click, buzz, hiss, knock, or chirp. Effective radiofrequencies range from 2.4 to 10 000 MHz, but an individual's ability to hear RF induced sounds is dependent upon high frequency acoustic hearing in the kHz range above about 5 kHz. The site of conversion of RF energy to acoustic energy is within or peripheral to the cochlea, and once the cochlea is stimulated, the detection of RF induced sounds in humans and RF induced auditory responses in animals is similar to acoustic sound detection. The fundamental frequency of RF induced sounds is independent of the frequency of the radiowaves but dependent upon head dimensions. The auditory response has been shown to be dependent upon the energy in a single pulse and not on average power density. The weight of evidence of the results of human, animal, and modeling studies supports the thermoelastic expansion theory as the explanation for the RF hearing phenomenon. RF induced sounds involve the perception via bone conduction of thermally generated sound transients, that is, audible sounds are produced by rapid thermal expansion resulting from a calculated temperature rise of only 5 Â 10 À6 8C in tissue at the threshold level due to absorption of the energy in the RF pulse. The hearing of RF induced sounds at exposure levels many orders of magnitude greater than the hearing threshold is considered to be a biological effect without an accompanying health effect. This conclusion is supported by a comparison of pressure induced in the body by RF pulses to pressure associated with hazardous acoustic energy and clinical ultrasound procedures. Bioelectromagnetics Supplement 6:S162-S173, 2003.

show abstract

“…The necessity to evaluate the ocular effects of MMW exposure was first mentioned by Gandhi and Riazi in 1986 [1]. Although many studies have assessed the effects of microwave exposure on the eye, few studies have evaluated the specific effects of MMWs [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of ocular temperature elevations after exposure to quasi- and millimeter waves (18-40 GHz)

Kojima

Suzuki

Tsai

et al. 2015

J Infrared Milli Terahz Waves

View full text Add to dashboard Cite

In order to investigate changes in ocular temperature in rabbit eyes exposed to different frequencies (18 to 40 GHz) of quasi-millimeter waves, and millimeter waves (MMW). Pigmented rabbits were anesthetized with both general and topical anesthesia, and thermometer probes (0.5 mm in diameter) were inserted into their cornea (stroma), lens (nucleus) and vitreous (center of vitreous). The eyes were exposed unilaterally to 200 mW/ cm 2 by horn antenna for 3 min at 18, 22 and 26.5 GHz using a K band exposure system or 26.5, 35 and 40 GHz using a Ka band exposure system. Changes in temperature of the cornea, lens and vitreous were measured with a fluoroptic thermometer. Since the ocular temperatures after exposure to 26.5 GHz generated by the K band and Ka band systems were similar, we assumed that experimental data from these 2 exposure systems were comparable. The highest ocular temperature was induced by 40 GHz MMW, followed by 35 GHz. The 26.5 and 22 GHz corneal temperatures were almost the same. The lowest temperature was recorded at 18 GHz. The elevation in ocular temperature in response to exposure to 200 mW/cm 2 MMW is dependent on MMW frequency. MMW exposure induced heat is conveyed not only to the cornea but also the crystalline lens.

show abstract

Absorption of Millimeter Waves by Human Beings and its Biological Implications

Cited by 192 publications

References 15 publications

The Effect of Insulating Layers on the Performance of Implanted Antennas

The Effect of Insulating Layers on the Performance of Implanted Antennas

Auditory response to pulsed radiofrequency energy

Characteristics of ocular temperature elevations after exposure to quasi- and millimeter waves (18-40 GHz)

Contact Info

Product

Resources

About