Base Transceiver Station Antenna Research Articles

Base transceiver station antenna exposure and workers’ health

Objectives. With the rapid development of technologies related to the communications industry, human exposure to electromagnetic fields has increased during recent decades. The study aimed at investigating the effect of exposure to waves emitted from the base transceiver stations (BTS) on workers' health. Methods. 240 workers participated in the study. In order to determine the general health conditions in two groups, along with electromagnetic waves exposure measurement, the general health questionnaire (GHQ) was completed and the data on blood parameters were assessed. Results. The mean age and job experience in the case and control groups were 34.1 ± 4.8 and 10.1 ± 6 years and 31.6 ± 5.5 and 8.8 ± 7 years, respectively. According to the GHQ results, only anxiety and insomnia subscales showed a significant difference between the two groups. The white blood cell and red blood cell counts in the case and control groups were 6715.6 ± 1591 and 7594 ± 2416, 5.3 × 106 ± 4.6 × 105 and 5.05 × 106 ± 5.39 × 105 per ml, respectively. Analysis of the results showed that the difference between the two groups was significant. Conclusion. The results revealed that blood parameters in the BTS operators showed more changes. Thus, it can be concluded that these health impacts result from occupational exposure to BTS waves.

Prenatal and early postnatal exposure to radiofrequency waves (900 MHz) adversely affects passive avoidance learning and memory.

Prenatal and early postnatal are the most sensitive and high-risk periods to expose to electromagnetic fields (EMFs). This study aimed to investigate the effect of prenatal and early postnatal exposure to 900 MHz radiofrequency waves (RFWs) emitted from a base transceiver station antenna on passive avoidance learning and memory (PALM) and hippocampus histomorphology. Female Sprague Dawley rats (190-230 g) were paired with males. The mated rats, confirmed by observing a vaginal plug, were divided into two groups; control and exposed. The control group (n = 7) was not exposed to RFW. The exposed group was divided into three subgroups (n = 8); exposed Ⅰ, exposed during the gestational period (fetal life), and exposed Ⅱ and Ⅲ (postnatal exposure), exposed to RFW during the first 21 days of life, for 2 h/d and 4 h/d, respectively. PALM was evaluated by a shuttle box in 45-day-old pups. Learning and memory of animals were demonstrated as the duration of remaining within the light area, which is called the lighting time. Histological sections were prepared from brain tissues and stained with hematoxylin and eosin. An impairment in the PALM performance was noticed in all exposed subgroups (Ⅰ, Ⅱ, and Ⅲ) (p < 0.05). Learning (short-term memory) and retention (long-term memory) behaviors were more affected in exposed subgroup Ⅰ (prenatal exposed) compared to other postnatal exposed subgroups (Ⅱ and Ⅲ). Also, a mild decrease in the density of pyramidal cells was observed in the hippocampus of exposed subgroups (Ⅰ and Ⅲ). Prenatal and early postnatal exposure to 900 MHz RFW adversely affected PALM performance and hippocampus tissue in rat pups with more impact for prenatal period exposure.

Effect of BTS on the quality of sleep and life of nearby residents

Introduction: Communication between mobile phones and antenna BTS (Base Transceiver station) is carried by electromagnetic waves that have energy, according to their nature. Increasing use of mobile phones because of the proliferation of antennas the concerns about them are proposed in society. In the present study the correlation between distance from the BTS antennas and the quality of sleep and quality of life have been investigated for residents of the surrounding population. Materials and Methods: For assess the quality of sleep the Pittsburgh Sleep Quality standard questionnaire was used and for quality of life the SF-12 questionnaire was used that contains two parameters: Mental Health Composite Scores = MCS and Physical Health Composite Scores = PCS. Results: Analysis of the data (810 people, including 411 females and 399 males) showed residents are living at a distance from 50 to 100 meters have the most sleep disturbance and the minimum average MCS score (p<0.05). Inhabitants who are within 100 to 200 meters from the antenna according to the Quality of Life Questionnaire have the fewer average PCS score rather than the other residents. Conclusion: The present study demonstrates that exposure to electromagnetic waves probably can affect the sleep quality, mental and physical life quality of the residents depended to distance from the BTS. It seems that antennas implant must be set in patterns that have the lowest intensity regarding to beam convergences for all residents.

On the Use of Unmanned Aerial Vehicles for Antenna and Coverage Diagnostics in Mobile Networks

The capability of in-situ antenna measurement and diagnostics using a compact low-cost unmanned aerial system is presented. An onboard power sensor collects amplitude-only measurements, which are processed by means of an iterative phase retrieval technique. This technique allows recovering an equivalent currents distribution, which characterizes the antenna under test (AUT). These currents can be used for antenna diagnostics as well as to evaluate the field radiated by the AUT. In the field of mobile networks, the proposed system is of interest for rapid assessment of the antenna's operational conditions, providing radioelectric coverage within the mobile network cells and allowing the evaluation of antenna failures, such as incorrect tilt or beamforming/ feeding network malfunction. A proof of concept of the system is conducted for testing a commercial base transceiver station antenna under normal and malfunctioning operation conditions, discussing the extension of the system to allow measurements at millimeter-wave frequency bands.

Reduction of squint in the slant polarised phased array antennas

The nature of the squint problem in the electrically tilted phased arrays (e.g. base transceiver station antennas) is explored based on the antenna theory and array theory. The antenna elements in the horizontal, vertical, or slant polarisations are considered. It is shown that the phased arrays with vertical and horizontal polarisations do not suffer from beam squint. However, it is illustrated that the issue of the squint becomes evident when one scans the beam along the vertical plane with slant antenna elements. A solution to reduce the squint problem is proposed which reduces the squint angle by a factor of two, and also improves the symmetry of the pattern.

Base Transceiver Station (BTS) Antenna Electric Field Influence on the Space Charge Region in a Silicon Solar Cell

In this study, we studied the influence of the electric field emitted by a BTS antenna on the space charge region of a silicon solar cell, placed at a distance r of the antenna. The drift diffusion recombination equation in presence of electric field has been established and the excess minority carries density is deduced. Based on the minority carries density, the space charge region extension, the photocurrent density, the photo voltage and the capacitance have been determined. The objective of his study is to show the effects of the electric field generated by a BTS antenna on the solar cell especially on the space charge region and its associated capacitance.

Investigation of Vertical Microwave Publishing Caused by the Base Transceiver Station (BTS) Antennas in Hashtgerd City

Background and Objectives: New Hazards interface the environment and human life along with technology development. One of these pollutants is electromagnetic field and it’s known and unknown bad effects on the environment, this study determines the vertical publishing (height measurement) of microwave antennas in the city of Hashtgerd. Methods: The basic information including the geographical location of the BTS antennas in the city, brand, the operator type, installation and its height was received from CRA and radio communications, and then the measuring was done by using the standard method of IEEE STD 95. 1 by the SPECTRAN 4060, and by using crane elevator in 17-meters height near the BTS antennas (15 meters).analysis were done by Spss16 and by Kolmogorov Smirnov test, multiple regression method. Results: Results show that in the both operators of Irancell and Hamrah-e-aval, density will increase by increasing measurement height or decreasing the vertical distance of broadcaster antenna. Regarding to the mix model test, a meaningful statistical relationship can be seen between measurement height and the density average in both types of the operators. Conclusion: while measuring height increased or in other words got closer to the antennas, density average increased in both operators, so the highest number was reported in the minimum vertical distance compared to the Irancell operator antenna was 25 mw/m2 and the lowest number was related to Hamrah-e-aval operator in the maximum vertical distance which was 0.02mw/m2. Thus, people stationed in the tall buildings parallel with installation height of antennas or in less vertical distance of them, are more exposed to the waves.

RETRACTED ARTICLE: Health Effects of Living near Mobile Phone Base Transceiver Station (BTS) Antennae: A Report from Isfahan, Iran

In recent years, by tremendous use of mobile phone telecommunication, a growing concern about the possible health hazards has increased greatly among public and scientists. The mobile phone exposure has been shown to have many effects upon the immune functions, stimulating hormones, mammalian brain, sperm motility and morphology, and neurological pathologies syndrome. The aim of this study was to find out the psychological and psychobiological reactions of the people who are living near mobile phone base transceiver stations (BTS) antenna, in Isfahan, Iran. A cross-sectional study on 250 randomly selected inhabitants (133 women and 117 men) was performed in October 2012 till November 2012. The inhabitants were requested to complete a standardized questionnaire that focused on the relevant psychological and psychobiological reactions parameters. A computer program (SPSS version16.0, Chicago, IL) was used for statistical analysis using the Chi-square test with Yates correction. All the data were tested using a criterion level of p = 0.05. The results showed that most of the symptoms such as nausea, headache, dizziness, irritability, discomfort, nervousness, depression, sleep disturbance, memory loss and lowering of libido were statistically significant in the inhabitants living near the BTS antenna (<300 m distances) compared to those living far from the BTS antenna (>300 m). It is suggested that cellular phone BTS antenna should not be sited closer than 300 m to populations to minimize exposure of neighbors.

The prophylactic effect of vitamin C on induced oxidative stress in rat testis following exposure to 900 MHz radio frequency wave generated by a BTS antenna model

Radio frequency wave (RFW) generated by base transceiver station (BTS) has been reported to make deleterious effects on reproduction, possibly through oxidative stress. This study was conducted to evaluate the effect of RFW generated by BTS on oxidative stress in testis and the prophylactic effect of vitamin C by measuring the antioxidant enzymes activity, including glutathione peroxidase, superoxide dismutase (SOD) and catalase, and malondialdehyde (MDA). Thirty-two adult male Sprague–Dawley rats were randomly divided into four experimental groups and treated daily for 45 days as follows: sham, sham+vitamin C (l-ascorbic acid 200 mg/kg of body weight/day by gavage), RFW (exposed to 900 MHz RFW) ‘sham’ and ‘RFW’ animals were given the vehicle, i.e., distilled water and the RFW+vitamin C group (received vitamin C in addition to exposure to RFW). At the end of the experiment, all the rats were sacrificed and their testes were removed and used for measurement of antioxidant enzymes and MDA activity. The results indicate that exposure to RFW in the test group decreased antioxidant enzymes activity and increased MDA compared with the control groups (p < 0.05). In the treated group, vitamin C improved antioxidant enzymes activity and reduced MDA compared with the test group (p < 0.05). It can be concluded that RFW causes oxidative stress in testis and vitamin C improves the antioxidant enzymes activity and decreases MDA.

Effect of short-term exposure to radio frequency emitted by base transceiver station (BTS) antenna on epididymal sperms

This study was conducted to assess the effect of short-term exposure to RF waves generated by BTS antenna on the viability and motility of stored sperm in different parts of the epididymis. One hundred testes from slaughtered bulls were collected and used for this study. The testes were divided into two groups, test and sham-exposed, each group, according to time of exposure to RF (1 to 5 h), was divided into five subgroups, ten in each group. After a defined time, the motility (tail of the epididymis) and viability of sperms (in three parts of the epididymis) were evaluated in both groups. In the head of the epididymis, the reduction of sperm viability observed in the test group was 13% (after 3 h), 18% (after 4 h) and 21% (after 5 h) compared to the sham-exposed group, which was statistically significant (P < 0.05). In the test group, sperm viability was significantly reduced in the body and tail sections after 4 and 5 h compared to the sham-exposed group (P < 0.05). After 3 h of exposure to RF, the percentage of progressive motility of sperm decreased (8.7%), while the percentage of slow progressive motility increased significantly (6.4%) after 4 h compared to the sham-exposed group (P < 0.05). These results suggested that short-term exposure to RF generated by mobile BTS has a deleterious effect on the quality of epididymal sperm (viability and motility) and that this effect is more severe in the head section and increases with increased exposure time.

Interference Suppression for Multiuser Downlink Transmission in Frequency-Selective Fading Channels

This paper presents an interference suppression scheme for multiuser downlink transmission in severe frequency-selective fading environments. Frequency-domain transmit beamforming and pre-equalization based on single-carrier frequency-domain equalization (SC-FDE) technique are employed to cancel co-channel interference (CCI) and to suppress intersymbol interference (ISI) with relatively low complexity. The proposed scheme effectively suppresses the ISI with a zero-forcing constraint on the CCI, and provides a viable solution to an otherwise analytically complex, if not unsolvable, problem. This paper also shows that, in frequency-selective fading channels, a multiuser system with K users and Mt base transceiver station antennas can offer lower bit error rate than a single-user system with Mt - K + 1 BTS antennas, if the proposed frequency-domain multiuser beamforming is employed.