DEMOCRATIC REPUBLIC OF CONGO MINISTRY OF HIGHER EDUCATION AND UNIVERSITY

HIGHER INSTITUTE OF APPLIED TECHNIQUES

KINDU MANIEMA

NETWORKS, MOBILE TELEPHONY AND BIOLOGICAL EFFECTS

BY

TUKA BIABA SAMUEL Garcia

Assistant and researcher at ISTA KINDU Province of Maniema of

Congo, Dept. of electricity: tukasamuel23@gmail.com

Year 2020-2021

Summary:

The development of mobile telephony was a new area of study, as it resulted for the first time in the exposure of populations to ultra-high frequency electromagnetic fields emitted by nearby sources (telephone antenna, relay antenna or BTS, ...). Electromagnetic radiation has given rise to multiple concerns regarding its potential effects on the health of the user of this technology, in the short and long term, over the past 15 years, when the cell phone appeared.

The possible effects of the electromagnetic waves used are of concern to researchers. And faced with the abundance of these strange radiations coming from our means of communication, a question arises concerning their effects on human health and in particular on biological tissues.

The electromagnetic interaction between mobile phone waves and biological tissues falls within the objectives of this research work, based on the effect of the presence of human tissues on the electromagnetic parameters of mobile phone networks and the effect of GSM waves on human health. Indeed, a biological system irradiated by an electromagnetic wave is crossed by induced currents of significant density.

The total electric field E in the biological system is unknown. An evaluation of the power distribution induced by an electromagnetic wave in a spherical model of the brain allows to say that, the quantity of energy received by the brain from the electromagnetic waves is very high compared to that which emerges from it by radiation, and that almost all of the energy received is transformed into heat.

The use of high frequencies, of the order of tens of gigahertz and more can cause non-thermal effects damaging to the health of an exposed biological system.

1 M. Plante, ''Cellulaires et santé'', l’électromagnétisme et la santé, le Médecin

du Québec, volume 45, numéro 4, avril 2010.

This depends on the frequency, intensity of these waves and the duration of exposure to them.

In this work we will mainly approach, the mathematical and numerical analysis using the method of moments as a basic tool allowing to model the total electric field and the distribution of electromagnetic power in the studied biological system, to estimate the effect of the exposure to non-ionizing radiation. And we tried to set precise limits that would protect man against the undesirable effects of this radiation. Then, the developed models will be simulated using Matlab software for their validity.

Keywords: Networks, mobile telephony, Method of moments, biological system, impact on health.

1.  Introduction

Since its inception, mobile phone networks and communications networks have evolved so much that they have become an essential communication tool. When the threads disappear, the waves take over, but this communication increasingly brings into play health effects. The RF field is the association of an electric field and a magnetic field which vary in time and propagate in space, these fields are likely to move electric charges, and are characterized by several physical  properties  including  main  are:  frequency,

wavelength, intensity and power [1][2].

So all living matter contains electric charges (ions,

molecules…) and insulating materials; it is therefore a weakly conductive medium (called a dielectric). Depending on the position of the cell phone relative to the human head, the tissue (layers of the head) is subjected to an RF field, part of the field is reflected, and the other enters the body. The radiation produced

2 II.4] P. Demaret, '' Effets biologiques des rayonnements électromagnétiques'', INRS, 7e Conférence Internationale, Malte, 8-12 octobre 2012.

by this interaction needs to be quantified, as it can cause biological effects. The field that penetrates inside the tissues can be calculated using electromagnetic models, and the dose of energy absorbed by transformation into heat is quantified by the power absorbed per unit mass of exposed biological material. It is defined by the

specific  absorption  rate  (SAR)[3][4].  So  the  vast

majority of radiation in our environment is of artificial

origin. Faced with the profusion of these strange radiations coming from our means of communication,

we   asked   ourselves   [5 ] and   it   therefore   seems necessary to ask yourself some questions to know [6]

ü     What were their effects on living things and in particular the human head?

ü     Do the waves emitted by our daily mobile phones present a health risk?

ü     What pathologies can occur depending on the frequency or intensity of "aggressive" waves or depending on the duration of exposure to them?

When a biological entity is subjected to electromagnetic fields, an interaction occurs with the electrical charges of the tissue or cell. The result of the interaction may produce a biological effect. This is a problem that concerns us all and to which a jump in consciousness is necessary insofar as most of us use cell phones, live at a more or less distant distance from relay antennas, from lines to high voltage or remain stuck for several hours a day in front of a computer screen or TV.

Although the short-term effects of such exposure are fairly well known, the scientific community is not unanimous on the long-term health effects.

Several epidemiological and experimental studies have been carried out on this subject and most of them have led to the establishment of biological effects that may

threaten medium or long term health. [7]. Theoretical

studies have also made it possible to estimate doses of

electromagnetic  energy  absorbed  by  animals  and

humans[8].

3 L. Hardell, C. Sage, “Biological effects from electromagnetic field exposure and public exposure standards”, Biomedicine & Pharmacotherapy 62 (2008), Elsevier Masson 31 December 2007, pp. 104 - 109.

4C. Sage, D. O. Carpenter “Public health implications of wireless technologies”, Pathophysiology (2009), Elsevier, January 2009, N°. of pages

14.

5 MOUMEN CHERIF : Op.cit. Page 1

6  T. B. Carlos KONLACK* et Roger TCHUIDJAN : Analyse de

l’impact des ondes électromagnétiques sur l’homme, Département des

It should be noted that this book deals with similar subjects while highlighting different aspects of the same general theme. We will consider for our application the particular case of a human brain subjected to electromagnetic radiation from the cell phone. And an emphasis is placed on estimating the effect of exposure to non-ionizing radiation.

Our work is aimed at supplementing and strengthening the veracity of some of the results already obtained. To do this, this work mainly addresses:

    Mathematical and numerical analysis using the method of moments as a basic tool to model the total electric field and the distribution of electromagnetic power in the studied biological system, to estimate the effect of exposure to non- ionizing radiation.

    Assessment of the SAR rate which is the basic limit quantity appearing in most regulations and standards relating to exposure to electromagnetic radiation.

    This rate is a measure of the rate at which electromagnetic energy is absorbed per unit mass of tissue.

    Set precise limits that would protect man against the undesirable effects of this radiation.

The models developed will be simulated using Matlab software for their validity.

2. Methodological Protocol

To carry out this study and better understand the distribution of the total electric field and electromagnetic power at various points in a biological system (human brain) and to predict possible health consequences there, we will proceed according to two approaches:

ü     mathematical analysis

ü     digital analysis

These approaches are based on the laws of electromagnetism and use the method of moments as processing tools. This is a digital study comprising:

ü    Presentation of the integral equation

ü    Processing and solving the integral equation.

Génies Électrique et des Télécommunications, ENSP B.P. 8390, Université de

Yaoundé I, Cameroun

7 De RIDDER et VANHOORNE « Exposition aux champs magnétiques

50Hz et cancer: Un aperçu de la littérature récente, », Archives of public

Health, Vol. 53, n°1-4 (1995) 35-52.

8OM P. GANDHI « State of Knowledge for electromagnetic absorbed dose in man and animals », Proceeding of IEEE, Vol. 68, N°1, January (1980).

ü     The change of form from the integral equation to the matrix equation.

ü    Calculations of the components of the matrix

ü    And finally the solution of the matrix equation

3. Study hypothesis

There is some need for approximation in our study. Indeed, biological systems are quite complex due to their geometric shape and the inhomogeneity of their internal constitution. This is how we formulate the hysteresis according to which for our study a biological system with one dielectric characterized by three main parameters which are:

ü  The permittivity ε: it is linked to the capacity of the

medium to be influenced by electric charges

ü  Magnetic permeability µ: It reflects the influence of the magnetic field on the environment

ü  Conductivity  σ:  It  reflects  the  capacity  of  the

medium to convey electric charges.

4.   Mobile    phone      network:      operation     and technical aspects:

Mobile phones are radio transceivers that communicate with cell towers. The frequencies currently used are in the 900 or 1800MHz (GSM) and 2100MHz (UMTS) range without forgetting the 2400MHz range corresponding to WiFi and Bluetooth for access to WiFi terminals or the use of accessories communicating with mobile phones. Bluetooth. The structure of the mobile network is cellular. The capacity of Base Stations (relay antennas) being limited, the size of the cells is larger in the countryside (several km) than

in the city (a few hundred meters) [9][10].

5.   Main  interactions  between  electromagnetic fields and living matter

Several  interactions  can  take  place  with  frequent exposure to an electromagnetic field.

This leads to short-term effects, direct (biological responses) or indirect. According to WHO, the current state of scientific knowledge does not demonstrate the long-term danger of exposure to low-intensity electromagnetic fields.

The interactions between electromagnetic waves and the human body are complex and depend on a large number of factors related to the characteristics of the wave and the biological tissue encountered. An electromagnetic field comprises two components: (an electric field and a magnetic field) thus, the nature of the interactions is different for each of these components.

The importance of these interactions depends on:

ü    Intensity

ü    Frequency

ü      The orientation of the electromagnetic field to which the tissue is exposed

ü    The geometry of the fabric and its electromagnetic

characteristics:

* Magnetic permeability (μ)

* Dielectric permittivity (ε)

* Conductivity (σ)

*The coupling between the field and the body, that is to say: tissues, organs

6.    Mathematical analysis and modeling

To be realistic in our research, we will highlight the

physical laws in particular[11] :

Maxwell-Faraday: ∇ × �⃗  = − ��⃗

��

Maxwell-Ampère: ∇ × �⃗  = �� +

��⃗⃗

��

(1)

(2)

Figure 1: the architecture of the mobile telephone network

9 Electrosmog-info, ''Téléphones Mobiles et Champs

Electromagnétiques'', V1, novembre 2010.

10 Ph. Piolé, ''Comment caractériser une antenne'', Fiche savoir

0123, 30 juillet 2004.

Maxwell-Gauss : ∇. �⃗   = �                    (3)

La loi d’Ohm : 𝑗 = ���⃗                          (4)

B⃗⃗  = μ0  ∗ H⃗                                                  (5)

D⃗⃗  = ε0 ∗ E⃗                                                   (6)

In   order   to   explain   the   actions   and   effects   of

electromagnetic waves on the human body.

11 Joseph Antoine BASSESUKA SANDOKA NZAO : Notes des cours des applications de l’énergie électriques, destinées aux étudiants finalistes du département d’électricité premier cycle de l’ISTA/KINSHASA RD Congo

The incident field ��  induces in the biological system

Si G⃗

� (r, r′ )�� represents the electric field produced

fields ��   which in turn induce currents of density �𝜏 by

virtue of equation (4) such that we can write:

by the elementary source then the combination of equations (10), (12) and (17) gives rise to:

𝑗⃗⃗𝜏  = [��(�, �, �) + ���[�(�, �, �) − �0 ]]�⃗ � (�, �, �)   (7)

Therefore, we have the Maxwell equations below:

× (     × G⃗ � (r, r )�� ) − 𝜗  G⃗⃗ � (r, r )��  = −�����0�(r − r ) (18)

This  makes  it  possible  to  obtain  the  following

solution:

1   �      �      ⃗

��                               𝜏

G�� (r, r′ ) = −���𝜇0 [1 +

��2  ��

(    )] G  (r, r′)�          (19)

��

�  × ��  = �����                                                                (9)

��

Avec    :   ��: three-dimensional      position    vector:

��(�, �, �)

The combination of equations (8) and (9) leads to:

Considering the three-dimensional Green function, we can write:

G⃗⃗ � (r, r′) = G⃗ �� (r, r′ )�� + G⃗⃗ �� (r, r′ )�� + G⃗ �� (r, r′)��  (20)

G⃗⃗ � (r, r′ )  Is  solution  of  the  following  differential

equation :

�  × ( �  × �� ) − ��2 ��  = −���𝜇 𝑗⃗⃗        (10)

�  × ( �

��

× G⃗ � (r, r

′)) − ��2G⃗⃗ � (r, r′)

= ℵ⃗ �(r − r′)  (21)

��           ��

0  𝜏

��

ℵ̃ = �� �� + �� �� + �� ��                                                         (22)

�  × ( �  × �� ) − ��2 ��  =  �  𝑗⃗⃗                     (11)

��           ��

��   𝜏

Or : ℵ̃ : represents the unit dyad and is defined

Avec :   ��2  = ��2 ��0 �0

𝜗 = ��√��0 �0

𝜗 : Phase coefficient in free space.

The solutions of equations (10) and (11) are written:

by :

Note: G⃗⃗ � (r, r′) is equal to the electric field at a point r

due to an infinitesimal source placed at r ’. From

equations (12) and (21) we can write:

�� (r) = −���μ0  ∫  G⃗ � (r, r′). J

r′  . dv′                        (23)

��  = −�𝜔 [1 +  1

�  ( � )] A⃗                            (12)

v′                          𝜏 (   )

��2 ��   ��

G⃗⃗ � (r, r′)  : as a singularity at r = r ’, so solution (23)

diverges if the point r considered is in the volume of

��  =  1

�  A⃗                                                         (13)

the biological system or in the source region.

��0 ��

Or : A⃗⃗ : vector potential :

A⃗   = μ0  ∫  G⃗⃗ � (r, r′ ). J (r′ ). dv′                                         (14)

v′                             𝜏

To solve the problem of divergence encountered in equation (23) one excludes in the field of integration a small volume surrounding the point r where one calculates the field, one will therefore add to the principal value β of the solution ( 23) a corrective