Electromagnetic interference of GSM mobile phones with the implantable deep brain stimulator,ITREL-III

Background

The purpose was to investigate mobile phone interference with implantable deep brain stimulators by means of 10 different 900 Mega Hertz (MHz) and 10 different 1800 MHz GSM (Global System for Mobile Communications) mobile phones.

Methods

All tests were performed in vitro using a phantom especially developed for testing with deep brain stimulators. The phantom was filled with liquid phantom materials simulating brain and muscle tissue. All examinations were carried out inside an anechoic chamber on two implants of the same type of deep brain stimulator: ITREL-III from Medtronic Inc., USA.

Results

Despite a maximum transmitted peak power of mobile phones of 1 Watt (W) at 1800 MHz and 2 W at 900 MHz respectively, no influence on the ITREL-III was found. Neither the shape of the pulse form changed nor did single pulses fail. Tests with increased transmitted power using CW signals and broadband dipoles have shown that inhibition of the ITREL-III occurs at frequency dependent power levels which are below the emissions of GSM mobile phones. The ITREL-III is essentially more sensitive at 1800 MHz than at 900 MHz. Particularly the frequency range around 1500 MHz shows a very low interference threshold.

Conclusion

These investigations do not indicate a direct risk for ITREL-III patients using the tested GSM phones. Based on the interference levels found with CW signals, which are below the mobile phone emissions, we recommend similar precautions as for patients with cardiac pacemakers: 1. The phone should be used at the ear at the opposite side of the implant and 2. The patient should avoid carrying the phone close to the implant.

     

A numerical and experimental comparison of human head phantoms for compliance testing of mobile telephone equipment

A new human head phantom has been proposed by CENELEC/IEEE, based on a large scale anthropometric survey. This phantom is compared to a homogeneous Generic Head Phantom and three high resolution anatomical head models with respect to specific absorption rate (SAR) assessment. The head phantoms are exposed to the radiation of a generic mobile phone (GMP) with different antenna types and a commercial mobile phone. The phones are placed in the standardized testing positions and operate at 900 and 1800 MHz. The average peak SAR is evaluated using both experimental (DASY3 near field scanner) and numerical (FDTD simulations) techniques. The numerical and experimental results compare well and confirm that the applied SAR assessment methods constitute a conservative approach.     

Combining near‐ and far‐field exposure for an organ‐specific and whole‐body RF‐EMF proxy for epidemiological research: A reference case

A framework for the combination of near‐field (NF) and far‐field (FF) radio frequency electromagnetic exposure sources to the average organ and whole‐body specific absorption rates (SARs) is presented. As a reference case, values based on numerically derived SARs for whole‐body and individual organs and tissues are combined with realistic exposure data, which have been collected using personal exposure meters during the Swiss Qualifex study. The framework presented can be applied to any study region where exposure data is collected by appropriate measurement equipment. Based on results derived from the data for the region of Basel, Switzerland, the relative importance of NF and FF sources to the personal exposure is examined for three different study groups. The results show that a 24‐h whole‐body averaged exposure of a typical mobile phone user is dominated by the use of his or her own mobile phone when a Global System for Mobile Communications (GSM) 900 or GSM 1800 phone is used. If only Universal Mobile Telecommunications System (UMTS) phones are used, the user would experience a lower exposure level on average caused by the lower average output power of UMTS phones. Data presented clearly indicate the necessity of collecting band‐selective exposure data in epidemiological studies related to electromagnetic fields. Bioelectromagnetics 34:366–374, 2013. © 2012 Wiley Periodicals, Inc.     

Metamaterial-Embedded Low SAR PIFA for Cellular Phone

A metamaterial-embedded planar inverted-F antenna (PIFA) is proposed in this study for cellular phone applications. A dual-band PIFA is designed to operate both GSM 900 MHz and DCS 1800 MHz. The ground plane of a conventional PIFA is modified using a planar one-dimensional metamaterial array. The investigation is performed using the Finite Integration Technique (FIT) of CST Microwave Studio. The performance of the developed antenna was measured in an anechoic chamber. The specific absorption rate (SAR) values are calculated considering two different holding positions: cheek and tilt. The SAR values are measured using COMOSAR measurement system. Good agreement is observed between the simulated and measured data. The results indicate that the proposed metamaterial-embedded antenna produces significantly lower SAR in the human head compared to the conventional PIFA. Moreover, the modified antenna substrate leads to slight improvement of the antenna performances.     

Testing the effectiveness of small radiation shields for mobile phones

Nine small radiation shields made to adhere to the case of mobile phones were tested at 914 and 1880 MHz. Five popular products were tested because advertisements typically claim they are up to 99% effective in blocking radio frequency (RF) radiation emitted from mobile phones. Also, four other conceptually unusual products were tested because advertisements typically claim they emit oscillations that counteract the RF radiation from mobile phones. Each shield was tested on the same mobile phone, and measurements were made to compare the absorption of RF energy in the head with and without each shield attached to the phone. The phone was positioned against a head model, and an automated measurement process was used to determine specific absorption rate (SAR) in the same way it is used at Motorola to test the compliance of mobile phones with respect to human exposure limits. The location of the peak SAR was not observed to change with any of the shields attached to the phone, and the 1 g, peak spatial average SAR did not change by any statistically significant amount. These results indicate the small shields are ineffective in reducing the exposure of the head to RF energy emitted by a mobile phone.     

Dosimetric assessment of an exposure system for simulating GSM and WCDMA mobile phone usage

An exposure system for investigation of volunteers during simulated GSM and WCDMA mobile phone usage has been designed. The apparatus consists of a dual band antenna with enhanced carrying properties that enables exposure for at least 8 h a day. For GSM a 900 MHz pulse modulated carrier was used. The QPSK modulated WCDMA signal at 1966 MHz comprises a power control scheme, which was designed for investigations of biological effects. The dosimetry of the exposure system by measurements and calculations is described in detail within this paper. It is shown that the SAR distribution of the antenna shows similar characteristics to mobile phones with an integrated antenna. The 10 g averaged localized SAR, normalized to an antenna input power of 1 W and measured in the flat phantom area of the SAM phantom, amounts to 7.82 mW/g (900 MHz) and 10.98 mW/g (1966 MHz). The simulated SAR(10 g) in the Visible Human head model agrees with measured values to within 20%. A variation of the antenna rotation angle results in an SAR(10 g) change below 17%. The increase of the antenna distance by 2 mm with respect to the human head leads to an SAR(10 g) change of 9%.     

Effects of weak mobile phone - electromagnetic fields (GSM, UMTS) on well-being and resting EEG

Modern mobile phones emit electromagnetic fields (EMFs) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. To date most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies were concerned with Universal Mobile Telecommunications System (UMTS)-EMF. Consequently, we tested the effects of both types of EMF, 1950 MHz UMTS (SAR 0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on well-being and vigilance-controlled resting electroencephalogram (eyes closed) in 15 healthy, right-handed subjects. A double-blind, randomised, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users.     

Hypersensitivity symptoms associated with exposure to cellular telephones: no causal link

The hypothesis that there exist hypersensitive persons who perceive subjective symptoms from radiofrequency (RF) fields emitted by hand held mobile phones (cellular phones) was tested using double blind provocation experiments. We also tested whether sensitive subjects are able to determine whether the phone is on or off by sensing RF fields. The study group consisted of 20 volunteers (13 women and 7 men) who reported themselves as being sensitive to cellular phones. The RF exposure sources were one analogue NMT phone (900 MHz) and two digital GSM phones (900 and 1800 MHz). The duration of a test session was 30 min, and three or four sessions were performed in random order for each subject during 1 day. The subjects were asked to report symptoms or sensations as soon as they perceived any abnormal feelings. In addition, the subjects' blood pressure, heart rate, and breathing frequency were monitored every 5 min. The results of the study indicated that various symptoms were reported, and most of them appeared in the head region. However, the number of reported symptoms was higher during sham exposure than during real exposure conditions. In addition, none of the test persons could distinguish real RF exposure from sham exposure. Hence, we conclude that adverse subjective symptoms or sensations, though unquestionably perceived by the test subjects, were not produced by cellular phones.     

Volume-averaged SAR in adult and child head models when using mobile phones: a computational study with detailed CAD-based models of commercial mobile phones

Previous studies comparing SAR difference in the head of children and adults used highly simplified generic models or half-wave dipole antennas. The objective of this study was to investigate the SAR difference in the head of children and adults using realistic EMF sources based on CAD models of commercial mobile phones. Four MRI-based head phantoms were used in the study. CAD models of Nokia 8310 and 6630 mobile phones were used as exposure sources. Commercially available FDTD software was used for the SAR calculations. SAR values were simulated at frequencies 900 MHz and 1747 MHz for Nokia 8310, and 900 MHz, 1747 MHz and 1950 MHz for Nokia 6630. The main finding of this study was that the SAR distribution/variation in the head models highly depends on the structure of the antenna and phone model, which suggests that the type of the exposure source is the main parameter in EMF exposure studies to be focused on. Although the previous findings regarding significant role of the anatomy of the head, phone position, frequency, local tissue inhomogeneity and tissue composition specifically in the exposed area on SAR difference were confirmed, the SAR values and SAR distributions caused by generic source models cannot be extrapolated to the real device exposures. The general conclusion is that from a volume averaged SAR point of view, no systematic differences between child and adult heads were found.     

Exposure assessment in front of a multi-band base station antenna

This study investigates occupational exposure to electromagnetic fields in front of a multi‐band base station antenna for mobile communications at 900, 1800, and 2100 MHz. Finite‐difference time‐domain method was used to first validate the antenna model against measurement results published in the literature and then investigate the specific absorption rate (SAR) in two heterogeneous, anatomically correct human models (Virtual Family male and female) at distances from 10 to 1000 mm. Special attention was given to simultaneous exposure to fields of three different frequencies, their interaction and the additivity of SAR resulting from each frequency. The results show that the highest frequency—2100 MHz—results in the highest spatial‐peak SAR averaged over 10 g of tissue, while the whole‐body SAR is similar at all three frequencies. At distances >200 mm from the antenna, the whole‐body SAR is a more limiting factor for compliance to exposure guidelines, while at shorter distances the spatial‐peak SAR may be more limiting. For the evaluation of combined exposure, a simple summation of spatial‐peak SAR maxima at each frequency gives a good estimation for combined exposure, which was also found to depend on the distribution of transmitting power between the different frequency bands. Bioelectromagnetics 32:234–242, 2011. © 2010 Wiley‐Liss, Inc.     

Effects of Low‐Intensity Microwave Radiation on Oxidant‐Antioxidant Parameters and DNA Damage in the Liver of Rats

The continuously increasing usage of cell phones has raised concerns about the adverse effects of microwave radiation (MWR) emitted by cell phones on health. Several in vitro and in vivo studies have claimed that MWR may cause various kinds of damage in tissues. The aim of this study is to examine the possible effects of exposure to low‐intensity MWR on DNA and oxidative damage in the livers of rats. Eighteen Sprague–Dawley male rats were divided into three equal groups randomly (n = 6). Group 1 (Sham‐control): rats were kept under conditions the same as those of other groups, except for MWR exposure. Group 2: rats exposed to 1800 MHz (SAR: 0.62 W/kg) at 0.127 ± 0.04 mW/cm² power density, and Group 3: rats exposed to 2,100 MHz (SAR: 0.2 W/kg) at 0.038 ± 0.03 mW/cm² power density. Microwave application groups were exposed to MWR 2 h/day for 7 months. At the end of the exposure period, the rats were sacrificed and DNA damage, malondialdehyde (MDA), 8‐hydroxydeoxyguanosine (8‐OHdG), and total oxidant‐antioxidant parameter analyses were conducted in their liver tissue samples. It was found that 1800 and 2100 MHz low‐intensity MWR caused a significant increase in MDA, 8‐OHdG, total oxidant status, oxidative stress index, and comet assay tail intensity (P < 0.05), while total antioxidant status levels (P < 0.05) decreased. The results of our study showed that whole‐body exposure to 1800 and 2100 MHz low‐intensity MWR emitted by cell phones can induce oxidative stress by altering oxidant‐antioxidant parameters and lead to DNA strand breaks and oxidative DNA damage in the liver of rats. Bioelectromagnetics. 2021;42:76–85. © 2020 Bioelectromagnetics Society     

Influence of dentures on SAR in the visible Chinese human head voxel phantom exposed to a mobile phone at 900 and 1800 MHz

To investigate the influence of dentures on electromagnetic energy absorption during the daily use of a mobile phone, a high-resolution head phantom based on the Visible Chinese Human dataset was reconstructed. Simulations on phantoms with various dentures were performed by using the finite-difference time-domain method with a 0.47 wavelength dipole antenna and a mobile phone model as radiation sources at 900 and 1800 MHz. The Specific energy Absorption Rate (SAR) values including 1 and 10 g average SAR values were assessed. When the metallic dental crowns with resonance lengths of approximately one-third to one-half wavelength in the tissue nearby are parallel to the radiation source, up to 121.6% relative enhancement for 1 g average SAR and 17.1% relative enhancement for 10 g average SAR are observed due to the resonance effect in energy absorption. When the radiation sources operate in the normal configuration, the 10 g average SAR values are still in compliance with the basic restrictions established by the Institute of Electrical and Electronic Engineers (IEEE) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP), indicating that the safety limits will not be challenged by the usage of dentures.     

Measurements of skin surface temperature during mobile phone use

We measured maximum temperature rises on the side of the face after 6 min of continuous mobile phone operation using two models of AMPS analog phones operating in the 835 MHz band and three early model GSM digital phones operating in the 900 MHz band. For the GSM phones the highest recorded temperature rise difference was 2.3 degrees C and for the AMPS phones it was 4.5 degrees C, both at locations on the cheek. The higher differential temperature rise between AMPS and GSM may reflect the higher maximum average operating power of AMPS (600 mW) versus GSM900 (250 mW). Additionally, we compared temperature changes at a consistent location on the cheek for an AMPS phone that was inoperative (-0.7 degrees C), transmitting at full power (+2.6 degrees C) and in stand-by mode (+2.0 degrees C). Our results suggest that direct RF heating of the skin only contributes a small part of the temperature rise and that most is due to heat conduction from the handset.     

SAR measurement due to mobile phone exposure in a simulated biological media

The specific absorption rate (SAR) measurements are carried out for compliance testing of personal 3G Mobile phone. The accuracy of this experimental setup has been checked by comparing the SAR in 10?gm of simulated tissue and an arbitrary shaped box. This has been carried out using a 3G mobile Phone at 1718.5?MHz, in a medium simulating brain and muscle phantom. The SAR measurement system consists of a stepper motor to move a monopole E-field probe in two dimensions inside an arbitrary shaped box. The phantom is filled with appropriate frequency-specific fluids with measured electrical properties (dielectric constant and conductivity). That is close to the average for gray and white matters of the brain at the frequencies of interest (1718.5?MHz). Induced fields are measured using a specially designed monopole probe in its close vicinity. The probe is immersed in the phantom material. The measured data for induced fields are used to compute SAR values at various locations with respect to the mobile phone location. It is concluded that these SAR values are position dependent and well below the safety criteria prescribed for human exposure.     

Cellular phone use does not acutely affect blood pressure or heart rate of humans

A recent study raised concern about increase of resting blood pressure after a 35 min exposure to the radiofrequency (RF) field emitted by a 900 MHz cellular phone. In this randomized, double blind, placebo controlled crossover trial, 32 healthy subjects were submitted to 900 MHz (2 W), 1800 MHz (1 W) cellular phone exposure, and to sham exposure in separate sessions. Arterial blood pressure (arm cuff method) and heart rate were measured during and after the 35 min RF and sham exposure sessions. We evaluated cardiovascular responses in terms of blood pressure and heart rate during controlled breathing, spontaneous breathing, head-up tilt table test, Valsalva manoeuvre and deep breathing test. Arterial blood pressure and heart rate did not change significantly during or after the 35 min RF exposures at 900 MHz or 1800 MHz, compared to sham exposure. The results of this study indicate that exposure to a cellular phone, using 900 MHz or 1800 MHz with maximal allowed antenna powers, does not acutely change arterial blood pressure and heart rate.     

SAR measurement due to mobile phone exposure in a simulated biological media

The specific absorption rate (SAR) measurements are carried out for compliance testing of personal 3G Mobile phone. The accuracy of this experimental setup has been checked by comparing the SAR in 10 gm of simulated tissue and an arbitrary shaped box. This has been carried out using a 3G mobile Phone at 1718.5 MHz, in a medium simulating brain and muscle phantom. The SAR measurement system consists of a stepper motor to move a monopole E-field probe in two dimensions inside an arbitrary shaped box. The phantom is filled with appropriate frequency-specific fluids with measured electrical properties (dielectric constant and conductivity). That is close to the average for gray and white matters of the brain at the frequencies of interest (1718.5 MHz). Induced fields are measured using a specially designed monopole probe in its close vicinity. The probe is immersed in the phantom material. The measured data for induced fields are used to compute SAR values at various locations with respect to the mobile phone location. It is concluded that these SAR values are position dependent and well below the safety criteria prescribed for human exposure.     

New fin-line devices for radiofrequency exposure of small biological samples in vitro allowing whole-cell patch clamp recordings

The development and analysis of three waveguides for the exposure of small biological in vitro samples to mobile communication signals at 900 MHz (GSM, Global System for Mobile Communications), 1.8 GHz (GSM), and 2 GHz (UMTS, Universal Mobile Telecommunications System) is presented. The waveguides were based on a fin‐line concept and the chamber containing the samples bathed in extracellular solution was placed onto two fins with a slot in between, where the exposure field concentrates. Measures were taken to allow for patch clamp recordings during radiofrequency (RF) exposure. The necessary power for the achievement of the maximum desired specific absorption rate (SAR) of 20 W/kg (average over the mass of the solution) was approximately P_in = 50 mW, P_in = 19 mW, and P_in = 18 mW for the 900 MHz, 1800 MHz, and 2 GHz devices, respectively. At 20 W/kg, a slight RF‐induced temperature elevation in the solution of no more than 0.3 °C was detected, while no thermal offsets due to the electromagnetic exposure could be detected at the lower SAR settings (2, 0.2, and 0.02 W/kg). A deviation of 10% from the intended solution volume yielded a calculated SAR deviation of 8% from the desired value. A maximum ±10% variation in the local SAR could occur when the position of the patch clamp electrode was altered within the area where the cells to be investigated were located. Bioelectromagnetics 32:102–112, 2011. © 2010 Wiley‐Liss, Inc.     

Effect of SAR on human head modeling inside cylindrical enclosures

This study intends to discuss enclosed a realistic approach to determine and analyze the effects of radio frequency on human exposure inside a cylindrical enclosure. A scenario in which a mobile phone with inverted-F antenna (IFA) operating in the Global System for Mobile Communication (GSM) band (900 MHz) is used inside a cylindrical enclosure. Metallic enclosures are known to have resonance and reflection effects, thereby increasing electric field strength and hence resulting in a change of the human exposure to electromagnetic absorptions. So, this study examines and compares the levels of absorption in terms of specific absorption rate (SAR) values under various conditions. In this study, a human phantom with dielectric properties is designed and its interaction is studied with IFA inside fully enclosed cylindrical enclosures. The results show that SAR values are increased inside cylindrical enclosures compared with those in free space. The method of computation uses method of moments. Simulations are done in FEKO software.     

Effect of GSM 900-MHz Mobile Phone Radiation on the Reproductive Capacity of Drosophila melanogaster

Pulsed radio frequency, (RF), electromagnetic radiation from common GSM mobile phones, (Global System for Mobile Telecommunications) with a carrier frequency at 900 MHz, “modulated” by human voice, (speaking emission) decreases the reproductive capacity of the insect Drosophila melanogaster by 50%–60%, whereas the corresponding “nonmodulated” field (nonspeaking emission) decreases the reproductive capacity by 15%–20%. The insects were exposed to the near field of the mobile phone antenna for 6 min per day during the first 2–5 days of their adult lives. The GSM field is found to affect both females and males. Our results suggest that this field-radiation decreases the rate of cellular processes during gonad development in insects.     

Analysis of proteome response to the mobile phone radiation in two types of human primary endothelial cells

Background  

Use of mobile phones has widely increased over the past decade. However, in spite of the extensive research, the question of potential health effects of the mobile phone radiation remains unanswered. We have earlier proposed, and applied, proteomics as a tool to study biological effects of the mobile phone radiation, using as a model human endothelial cell line EA.hy926. Exposure of EA.hy926 cells to 900 MHz GSM radiation has caused statistically significant changes in expression of numerous proteins. However, exposure of EA.hy926 cells to 1800 MHz GSM signal had only very small effect on cell proteome, as compared with 900 MHz GSM exposure. In the present study, using as model human primary endothelial cells, we have examined whether exposure to 1800 MHz GSM mobile phone radiation can affect cell proteome.