Section IV. Methodology for measuring and estimating emp parameters. Methods for monitoring the strengths of the electric and magnetic components of the emp. General principles for measuring the parameters of the electromagnetic field

EMR RF and microwave are characterized by three main parameters: electric field strength (E), magnetic field strength (H) and energy flux density (EFE), more correctly - Power Flux Density (PFM). The assessment of RF and microwave intensity in different ranges is not the same. In the radio frequency range of less than 300 MHz (as recommended by the International Organization IRPA / INIRC (International Committee on Non-Ionizing Radiation / International Radiation Protection Association) - less than 10 MHz), the radiation intensity is expressed by the strength of the electrical and magnetic components and is determined, respectively, in volts per meter (V /m) (or kilovolts per meter (kV/m):

1 kV/m = 103 V/m) and amperes per meter (A/m). In the microwave range, i.e. above 300 MHz, intensity, or RPM, is expressed in watts per square meter (W / m2; 1 W / m2 = 0.1 mW / cm 2 = 100 μW / cm 2). To characterize magnetic fields, a value is introduced, called the magnetic field induction (V), equal to the force with which the magnetic field acts on a single current element located perpendicular to the induction vector. The unit of MF induction is the tesla (T). To characterize the magnetic field in a vacuum, a quantity is introduced, called the magnetic field strength (N), measured in amperes per meter (A / m). The intensity and induction of the magnetic field are related by the relationship: B=m m0 N, where m0 is the magnetic constant equal to 4×10-7 H/m; m is the relative magnetic permeability of substances. (1A / m \u003d 1.256 × 10-6 T. The off-system unit of magnetic induction is gauss (Gs): 1Gs \u003d 10-4 T; MF strength is oersted (Oe): 1E \u003d 79.58 A / m. In air 1 H = 1 O. In addition, the term "gamma" is used, denoting a value that is equal to 1 nT.

As for cell phones, today the level of safety of a cell phone is usually assessed in SAR (Specific Absorption Rates) - by the level of radiation (emission) of radiated energy in watts per kg of brain matter (W / kg). The lower the SAR value, the safer the device.

Instruments for measuring electromagnetic radiation

Various devices are used to measure electromagnetic radiation, as examples, consider the following:

IESP-01 (A) - electrostatic potential meter
The IESP-01 meter (option A) is designed to measure the electrostatic potential of display screens at workplaces with computer equipment and for certification of displays according to the requirements of GOST R.

IESP-01 (V) - electrostatic potential and field intensity meter
The IESP-01 meter (version B) is designed to measure the electrostatic potential of display screens at workplaces with computer equipment and for certification of displays according to the requirements of GOST R, as well as to measure the strength of the electrostatic field.

IEP-05 - electric field meter
The electric field meter IEP-05 is designed to measure the root mean square value of the intensity of alternating electric fields created by various technical means.

IMP-05 - magnetic field meter
Magnetic field meter IMP-05 is designed to measure the root mean square value of magnetic induction (magnetic flux density) of electromagnetic fields generated by various technical means

BE-METR-AT-002 — electric and magnetic field parameters meter
Measuring tool for certification of workplaces of computer operators in accordance with SanPiN 2.2.2/2.4.1340-03 and for certification of video terminals according to the MPR and TCO 92/95 standards. Simultaneous measurements of the electrical and magnetic components of the electromagnetic field in two frequency bands: from 5 Hz to 2 kHz and from 2 kHz to 400 kHz.

BE-50 - industrial frequency electromagnetic field meter
Meters of parameters of magnetic and electric fields of industrial frequency BE-50 are intended for measurement of effective values ​​of magnetic field induction (elliptically polarized) and intensity of electric field of industrial frequency of 50 Hz.

ATT-8701 - magnetic field strength meter
Measurement of constant and variable magnetic fields. Measurement ranges: — 3000 mGs … 3000 mGs or — 300.0 µT … 300.0 µT. Resolution 1 mGs / 0.1 µT. Retention of evidence. Record Max, Min. RS-232 interface. Power: 6 x 1.5V (UM-4/AAA) or 9V DC adapter.

ATT-8504 - magnetic field strength meter
Magnetic field strength meter ATT-8504: 0.01…2000 mH or 0.001…200 µT; Frequency range 30 Hz…2 kHz; Work on 3 axes: X, Y, Z; Memory for 2000 results; RS-232 interface; Data transfer to PC; Power supply 6 x 1.5 V; Dimensions: 154x72x35 mm; Weight 165 g

Broadband field strength meter NBM – 550
NBM – 550, a broadband field strength meter, is one of the devices in the NARDA NBM – 500 line, It allows you to obtain ultra-precise measurement results for non-ionizing radiation. The set includes probes for measuring the intensity of electric and magnetic fields; NBM - 550, covers all frequencies from longwave to microwave radiation.

Electromagnetic radiation meter EFA - 200, EFA - 300
The electromagnetic radiation meter EFA - 200, EFA - 300, manufactured by NARDA, is one of the most advanced means of controlling the MF IF intensity at present, designed to control the root mean square and amplitude values ​​of the magnetic field in the frequency range from 5 Hz to 32 kHz. As a primary converter in the analyzer EFA - 200, EFA - 300, a built-in or external isotropic loop antenna is used, consisting of three mutually perpendicular inductors. Due to the wide use of modern element base and digital signal processing in the analyzer EFA - 200, EFA - 300, it was possible to achieve high accuracy (± 3-5%) and a large dynamic range (40 nT - 10 mT) of magnetic field measurements with advanced additional functions ( digital signal filtering, measurement data memory, results processing and computer control, the possibility of automatic monitoring of magnetic field levels, etc.), as well as small weight and dimensions.

SRM - 3000 Electromagnetic Field Characteristics Meter
The SRM-3000 is a portable instrument designed for the safe measurement of electromagnetic field characteristics. The SRM - 3000 includes a base unit with a 100 kHz - 3 GHz spectrum analyzer and a Narda three-channel measuring sensor. The three-channel sensor allows for isotropic (non-directional) measurements covering the frequency range from FM to U-CDMA and UMTS. In addition, it is possible to equip the SRM-3000 with measuring antennas from other manufacturers.

• Frequency range from 100 kHz to 3 GHz,
• Isotropic measurements with a three-channel probe (75 MHz - 3 GHz),
• Weak susceptibility to electromagnetic fields,
• Display results in V/A, A/m, W/m or as a percentage of the allowed value
• Automatic recalculation of measurement results for TETRA, GSM, UMTS systems using special tables,
• Automatic calculation of the parameters of individual devices that affect the total value of the electromagnetic field radiation,
• Bandwidth up to 5 MHz for UMTS and W-CDMA systems,
• UMTS P-CPICH mode for measuring the effect of radiation from UMTS base stations.

EMF measurement methods are based on various physical effects, for example,

force interaction of the MF with the magnetic moment of a physical object or particles of matter,

excitation of the induction EMF in the inductor in an alternating MF,

change in the trajectory of electric charges moving in the MP under the influence of a deflecting force,

thermal effect of EMF on the radiation receiver, etc.

The requirements for modern electronic technology, such as: increasing reliability and noise immunity, reducing prices, dimensions, power consumption - also apply to sensors. The fulfillment of these conditions becomes possible when using microelectronic circuitry and technology, because:

firstly, the electrophysical properties of semiconductors and semiconductor devices, on which microcircuitry is based, strongly depend on external influences;

secondly, microelectronic technology is based on group methods of processing materials for the manufacture of devices, which reduces their cost, dimensions, power consumption and leads to an increase in reliability and noise immunity.

In addition, when using a semiconductor sensor or a sensor whose manufacture is compatible with the technological process for creating integrated circuits (ICs), the sensor itself and the received signal processing circuits can be manufactured in a single technological cycle, on a single semiconductor or dielectric crystal.

The most common microelectronic magnetic transducers include: Hall elements; magnetoresistors; magnetotransistors and magnetodiodes; magnetic recombination transducers.

1. Optical methods for obtaining information

Optics is a branch of physics that studies the nature of optical radiation (light), its propagation and phenomena observed during the interaction of light and matter

Light has a dual structure and exhibits both wave and particle properties. From the wave point of view, light represents electromagnetic waves that lie in a certain range of frequencies. The optical spectrum occupies a range of electromagnetic wave lengths in the range from 10 -8 m to 2*10 -6 m (in frequency from 1.5*10 14 Hz to 3*10 16 Hz). The upper limit of the optical range is determined by the long-wavelength limit of the infrared range, and the lower limit - by the short-wavelength limit of the ultraviolet. Wave properties are manifested in the processes of diffraction and interference. From a corpuscular point of view, light is a stream of moving particles (photons). The connection between the wave and corpuscular parameters of light is established by the de Broglie formula, where λ is the wavelength, R is the momentum of the particle, h- Planck's constant, equal to 6.548 × 10 -34 J s (in the SI system).

Optical research methods are distinguished by high accuracy and visibility.

1. optical microscopy

Optical devices such as microscopes are used to study and measure objects of small objects. The class of optical microscopes is very diverse and includes optical, interference, luminescent, infrared, etc.

A microscope is a combination of two optical systems - an objective and an eyepiece. Each system consists of one or more lenses.

An object is placed in front of the objective lens, and an ocular lens is placed in front of the observer's eye. For a visual representation of the passage of light through an optical system, the representations of geometric optics are used, in which the main concept is a beam of light, the direction of the beam coincides with the direction of the wave front.

A schematic diagram of image acquisition in an optical microscope is shown in Fig.1.

For ease of constructing an image in the figure, the lens system of the objective is replaced by a single converging lens L 1 , and the lens system of the eyepiece is the lens L 2 . Thing AB placed in front of the focal plane of a lens that creates an enlarged real image A"B" object near the front focus of the eyepiece. Image A"B" is slightly closer to the front focus of the eyepiece F 2 . In this case, the eyepiece creates an enlarged virtual image. A"B", which is projected at the distance of best vision and viewed through the eyepiece by the eye.

An optical microscope is characterized by the following main parameters: magnification, resolution, depth of focus (sharpness), field of view.

Increase is determined by the magnifying power of all lenses included in the path of optical rays. It can be assumed that by appropriately selecting the magnification values ​​of the objective and the eyepiece, one can obtain a microscope with an arbitrarily high magnification. However, in practice, microscopes with a magnification of more than 1500–2000 times are not used, since the ability to distinguish fine details of an object in a microscope is limited. This limitation is due to the influence of light diffraction occurring in the structure of the object under consideration. Due to the wave nature of light, the image of each point of the object in the image plane has the form of concentric dark and light rings, as a result of which closely spaced points of the object merge in the image. In this regard, the concepts of the resolution limit and the resolution of the microscope are introduced.

resolution limit microscope is the smallest distance between two points of an object when these points are distinguishable, i.e. perceived under the microscope as not merging with each other.

The resolution limit is determined by the formula δ=0.51 λ/A, value A=n sin u called the numerical aperture of the microscope; λ - wavelength of light illuminating the object; n- the refractive index of the medium between the lens and the object; u- aperture angle of the objective, equal to half the angle between the extreme rays of the conical light beam entering the microscope objective.

Data about each lens is marked on its body with the following parameters:

increase ("x" - multiplicity, size);

numerical aperture: 0.20; 0.65, example: 40/0.65 or 40x/0.65;

additional letter marking if the lens is used for various methods of examination and contrasting: phase - F, polarization - P (Pol), luminescent - L ( L), etc.

marking of the type of optical correction: apochromat - APO (APO), planachromat - PLAN (PL, Plan),.

Resolution microscope is called the ability of a microscope to give a separate image of small details of an object. Resolution is the reciprocal of the resolution limit ξ = 1/δ.

As can be seen from the formula, the resolution of the microscope depends on its technical parameters, but the physical limit of this parameter is determined by the wavelength of the incident light.

The resolving power of a microscope can be increased by filling the space between the object and the objective with an immersion liquid with a high refractive index.

Depth of field is the distance from the closest plane to the farthest plane of an object that is rendered acceptably focused.

If the points of the object are at different distances in front of the lens (in different planes), then the sharp images of these points formed by it will also be at different distances behind the lens. This should mean that sharp images can only be formed by points lying in the same plane. The remaining points in this plane will be displayed as circles, which are called scatter circles. (Fig. 2).

The size of the circle depends on the distance from the given point to the display plane. Due to the limited resolution of the eye, points displayed by small circles will be perceived as points and the corresponding object plane will be considered as being in focus. The depth of field is the greater, the shorter the focal length of the lens, the smaller the diameter of the active hole (the diameter of the lens barrel or aperture hole). Figure 2 shows the dependence of the depth of field on the listed factors. Other things being equal, that is, with F constant and also constant distance from the lens to the object, to increase the depth of field, the diameter of the active hole is reduced. For this purpose, a diaphragm is installed between the objective lenses, which makes it possible to change the diameter of the inlet.

line of sight optical system - part of the space (plane) represented by this system. The size of the field of view is determined by the details included in the system (such as frames of lenses, prisms and mirrors, diaphragms, etc.), which limit the beam of light rays.

Instrumental control of EMF levels is carried out in order to determine the actual state of the electromagnetic environment in the areas where radiating means are located and serves as a means of assessing the reliability of the calculation results.

Measurements are taken:

At the stage of preventive sanitary supervision - upon acceptance of a radio engineering facility (RTO) into operation;

At the stage of current sanitary supervision - when changing technical characteristics or operating modes (radiation power of the antenna-feeder path, radiation directions, etc.);

When situational conditions for the placement of stations change (change in the location of antennas, their installation heights, azimuth or elevation angle of maximum radiation, development of adjacent territories);

After carrying out protective measures aimed at reducing the levels of EMF;

In the order of planned control measurements (at least once a year).

4.1. Preparing to take measurements

In preparation for the measurements, the following work is carried out:

Coordination with interested enterprises and organizations of the purpose, time and conditions of measurements;

Reconnaissance of the measurement area;

The choice of tracks (routes) and measurement sites, while the number of tracks is determined by the terrain adjacent to the object, and the purpose of the measurements;

Organization of communication to ensure interaction between the station personnel and the measurement group;

Ensuring distance measurements to the measurement point;

Determining the need to use personal protective equipment;

Preparation of the necessary measuring equipment.

4. 2. Selection of traces (routes) of measurements

The number of traces is determined by the relief of the surrounding area and the purpose of the measurements. When establishing the boundaries of the C33, several routes are selected, determined by the configuration of the theoretical boundaries of the C33 and the adjacent residential area. Under the current sanitary supervision, when the characteristics of the station and the conditions of its operation remain unchanged, measurements can be carried out along one characteristic path or along the C33 boundary.

When choosing routes, the nature of the surrounding area (relief, vegetation, buildings, etc.) is taken into account, in accordance with which the area adjacent to the station is divided into sectors. In each sector, a radial, relative to the station, track is selected. The requirements for the track are:

The path must be open, and the sites where the behavior of the measurements is planned must have a direct line of sight to the antenna of the radiating means;

Along the route, within the main lobe of the radiation pattern, there should be no re-emitters (metal structures and structures, power lines, etc.) and other obscuring local objects;

The slope of the path should be minimal compared to the slope of all possible paths in the given sector;

The route must be accessible to pedestrians or vehicles;

The length of the route is determined on the basis of the estimated distance of the C33 boundaries and the depth of the development restriction zone (1.5 - 2 times more);

Points (sites) for measurements should be selected with an interval of no more than 25 m - at a distance of up to 200-300 m from the emitting antenna; 50-100 m - at a distance from 200-300 m to 500-1000 m; 100 m and more - at a distance of more than 1000 m.

When choosing sites for measurements, it should be taken into account that there are no local objects within a radius of up to 10 m and that direct visibility to the radiating antenna is provided from any of its points.

4.3. Taking measurements

The equipment used to measure EMF levels must be in good working order and have a valid certificate of state verification.

Preparation of equipment for measurements and the measurement process itself is carried out in accordance with the operating instructions for the device used.

At the stage of current sanitary supervision, when the technical characteristics of the RTO, the conditions and mode of its operation remain unchanged, measurements can be carried out along one characteristic route or along the border of the sanitary protection zone.

The measuring antenna of the device is oriented in space in accordance with the polarization of the measured signal.

Measurements are made in the center of the site at a height of 0.5 to 2 m. Within these limits, the height is found at which the deviation of the instrument readings is greatest, at this height, smoothly turning the measuring antenna in the horizontal, and, if necessary, in the vertical plane, again consistently achieve the maximum instrument readings . The maximum value of the measured value is taken as reference.

At each site, at least three independent measurements should be carried out. The result is the arithmetic mean of these measurements.

Measurements of the zero strength of each technical means are carried out using the FSM-8 set, which is included in the mode of measuring effective values ​​at the carrier frequencies of the video and audio channels.

The resulting value of these measurements is found according to formula 3.9.

Measurements can be made with other devices with similar parameters.

To measure the distance from the base of the support to the measurement point, a theodolite, a measuring tape, a plan (map) of the area and other available methods that provide sufficient accuracy can be used.

According to the measurement results, a protocol is drawn up. The results of measurements should be entered in the sanitary passport of the RTO and brought to the attention of its administration.

P3-50A - Power frequency field strength meter, high-quality professional equipment, PZ-50 A, characteristics and technical description of the model, order P3-50 A from the SamaraPribor company, buy Power frequency field strength meter with delivery and warranty, Instruments for measuring electromagnetic fields and radiation as well as other measuring instruments (instrumentation) laboratory and test equipment in a wide range at an attractive price.

The method for measuring the strength of the electromagnetic field consists in placing antenna-sensors in the measured electromagnetic field K and recording the voltages on the load element K of the antenna-sensors U 1 .... U K , proportional to the strength of the acting electromagnetic field, all K antenna-sensors have distinctive amplitude-frequency characteristics, the number of sensor antennas K is equal to the number of radiation sources N or exceeds it, K N, the intensity of all N components of the electromagnetic field E 1 .... E N is determined from the solution of a system of linear equations. The technical result is to increase the accuracy of measurements, to determine the intensity of all components of the field. 1 ill., 1 tab.

The invention relates to the field of measurement, namely to the section "measuring the magnetic field strength" (class G 01 R 29/08), and can be used to measure the intensity of electromagnetic fields of radio frequencies in the environment, to determine the safety of personnel and solve other similar problems.

Known methods for measuring electromagnetic fields of radio frequencies are based on placing the antenna-sensor in the measured field and recording the voltage induced by the measured field in the load of the receiving antenna-sensor, followed by the calculation of the field strength using known dependencies that relate the value of the field strength and the parameters of the sensor and load (see AN Zaitsev's book "Microwave measurements and their metrological support", M. 1989, p. 163, or Adolf I. Schwab "Electromagnetic compatibility", M. 1998, p. 254). This method is used in measurements at relatively low radio frequencies, in the microwave frequency range a similar method is used, differing in that the power released in the load of the receiving antenna-sensor is recorded when the antenna-sensor is placed in the measured field, and when recalculating the measured value, dependencies are used that connect the value of the released power with the parameters of the antenna-sensors and the power flux density of the measured field (see the book by A.N. Zaitsev "Measurement on the microwave and their metrological support", M. 1989, p. 164).

These measurement methods are implemented using various options for performing antenna-sensors (see USSR Patent A1 1649478 for 1991) in measuring instruments designed to measure the level of electromagnetic fields in order to determine levels hazardous to life, for example, in domestic devices of the type: PZ -16 ... PZ-21, as well as in the latest modification Pole-3, the essence of which is to measure from the output of sensor antennas designed to operate in their frequency range, a voltage proportional to the field strength. In this case, the coefficients of proportionality for each sensor antenna in its range are known.

Methods for frequency-selective measurements are also known, in which the electrical oscillations received by the receiving antenna-sensor and containing oscillations of various frequencies are filtered using band-pass filters, amplify, detect, measure and record the output voltage (see the book by A.N. Zaitsev " Microwave measurement and their metrological support", M. 1989, p. 174).

The method of frequency-selective measurements is mainly used for measuring relatively weak fields. The methods are implemented in various measuring receivers, selective microvoltmeters, which are complex and expensive devices.

The prototype of the invention is a method for measuring the field strength by placing a sensor antenna in the measured field and recording a voltage proportional to the measured strength in the load of the sensor antennas (see the book by A. N. Zaitsev "Microwave measurement and their metrological support", M. 1989 g., p. 163).

The method consists in placing the sensor antenna in the measured field, recording the voltage created by the measured field in the load of the receiving antenna, and determining the electric field strength according to a known relationship linking the value of the measured field strength with the electrical parameters of the sensor antenna and load.

This dependence has the form

E - electric field strength, V/M;

h g (f) - equivalent height of the antenna-sensor, M;

Z n (f) - load resistance of the antenna-sensor, Ohm;

Z a (f) - equivalent resistance of the antenna-sensor, Ohm;

K(f) - the value of the amplitude-frequency characteristic in frequency, M.

The disadvantage of the prototype is the inability to accurately determine the field strength generated by the source at a certain frequency f 1 due to interference from sources emitting at other frequencies f i , where i = 2...N, as well as the impossibility of determining the strength of the electromagnetic field generated by these sources of interference . The voltage induced in the load of the sensor antennas when exposed to N radiation sources with frequencies f i will be determined by the expression

where U - voltage at the output of the antenna-sensor, V;

K(f i) - the value of the amplitude-frequency characteristic at the radiation frequency of the i-th source (f i), M;

E i - electric field strength at the radiation frequency of the i-th source (f i), V/M;

f i - radiation frequencies of the i-th source, Hz;

N is the number of radiation sources in the measured field.

Thus, in real conditions, due to the finite susceptibility of the antenna-sensor radiation with frequencies that are not included in the frequency range of the applied antenna-sensor, the measurement of the true value of the field strengths becomes impossible.

The P3-80 meter is designed to measure the root-mean-square values ​​of the intensity of alternating electric (AEL) and magnetic (NMF) fields and industrial sources in the frequency range of 5-500000 Hz, as well as to measure the intensity of electrostatic fields (ESF).

The main area of ​​application is the control of the electromagnetic environment, the measurement of industrial radio interference, the measurement of biologically hazardous levels of electromagnetic fields in accordance with SanPiN 2.2.4.1191-03, as well as for scientific research.

The meter meets the requirements of GOST 22261, and according to the operating conditions it belongs to group 4 according to GOST 22261-94. The device does not contain flammable, explosive and other substances hazardous to human health and life.

The meter is supplied with the following configuration.

Digital converter of the electromagnetic field P3-80-EN500.

Digital electrostatic field converter P3-80-E.

Indicator unit (IB) type ECOPHYSICS-D1 (complete with a set of batteries: 4 cells type AA (LR6)).

Operational documentation: operation manual, passport.

Technical characteristics of the device P3-80

Operating frequency range of the meter

With converter P3-80-EN500: from 0.005 to 500 kHz.

Measured parameters

In P3-80-E400 (P3-80-H400) mode

Current, maximum and minimum RMS values ​​of NEP (NMP) in 27 bands in the range from 25 to 675 Hz;

Current, maximum and minimum RMS values ​​of the NEP (NMP) in the bands 10 kHz - 30 kHz; 5-2000 Hz, 2 kHz - 400 kHz.

In P3-80-E300 (P3-80-N300) mode

Current, maximum and minimum RMS values ​​of NEP (NMP) on characteristics 30-300 Hz, 300-3000 Hz, 3 kHz-30 kHz, 30 kHz-300 kHz with reference frequencies 50 Hz, 500 Hz, 10 kHz, 100 kHz.

MUK 4.3.1677-03

METHODOLOGICAL INSTRUCTIONS

4.3. CONTROL METHODS. PHYSICAL FACTORS

Determination of the levels of the electromagnetic field created by radiating
technical means of television, FM broadcasting and base stations
land mobile radio

Date of introduction: from the moment of approval

1. DEVELOPED by employees of the Samara Branch Research Institute of Radio of the Ministry of the Russian Federation for Communications and Informatization (A.L. Buzov, S.N. Eliseev, L.S. Kazansky, Yu.I. Kolchugin, V.A. Romanov, M .Yu.Spobaev, D.V.Filippov, V.V.Yudin).

2. Submitted by the Ministry of Communications of Russia (letter N DRTS-2/988 dated December 2, 2002). Approved by the Commission on State Sanitary and Epidemiological Regulation under the Ministry of Health of Russia.

3. APPROVED AND PUT INTO EFFECT by the Chief State Sanitary Doctor of the Russian Federation on 29.06.03.

4. INTRODUCED to replace MUK 4.3.045-96 and MUK 4.3.046-96 (in terms of base stations).

Purpose and scope

The guidelines are intended for use by specialists of the centers of state sanitary and epidemiological surveillance, engineering and technical workers, design organizations, telecom operators in order to ensure sanitary and epidemiological surveillance of radiation sources.

The guidelines establish methods for determining (calculating and measuring) the levels of the electromagnetic field (EMF) emitted by technical means of television, FM broadcasting and base stations of land mobile radio communications in the range of 27-2400 MHz at their locations.

The document was introduced to replace MUK 4.3.04-96* and MUK 4.3.046-96 (regarding base stations). It differs from previous documents in that it contains a method for calculating EMF levels for arbitrary distances from antennas, including the near zone, taking into account the underlying surface and the influence of various metal structures.
_____________
*Probably an original error. You should read MUK 4.3.045-96. - Note "CODE".

The guidelines do not apply to communication facilities containing aperture antennas.

1. General Provisions

1. General Provisions

The determination of EMF levels is carried out in order to predict and determine the state of the electromagnetic environment at the locations of emitting objects of television, FM broadcasting and base stations of land mobile radio communications.

Estimated forecasting is carried out:

- when designing a transmitting radio engineering facility (PRTO);

- when the placement conditions, characteristics or modes of operation of the technical means of the operating PRTO change (change in the location of antennas, their installation heights, radiation directions, radiation power, antenna-feeder path scheme, development of adjacent territories, etc.);

- in the absence of materials for the calculation forecasting of the electromagnetic environment of the PRTO;

- upon commissioning of the PRTO (when changes are made to the project relative to its original version, for which computational forecasting was carried out).

Measurements are taken:

- when the PRTO is put into operation;

- in the order of scheduled control measurements at least once every three years (depending on the results of dynamic monitoring, the frequency of measurements of EMF levels can be reduced by decision of the relevant center of state sanitary and epidemiological surveillance, but not more than once a year);

- when changing the conditions of placement, characteristics or modes of operation of the technical means of the existing PRTO;

- after carrying out protective measures aimed at reducing EMF levels.

In the method of computational forecasting, the following methods for calculating EMF levels are defined:

- directly by the current in the antenna conductors (preliminarily calculated);

- according to the radiation pattern (DN) of the antenna, which is determined by the distribution of current in the antenna conductors;

- according to the passport DN of the antenna.

For those cases when the antenna is an antenna array, the elements of which are emitters of an unknown design with known RPs, it is possible to calculate the RP of such an array.

The calculation of EMF levels directly from the current is performed for relatively small distances from the antenna (in the near and intermediate zones), the calculation by RP is for relatively large distances (in the far zone). Passport DNs are used in the absence of information about the design of the antenna.

The current distribution along the antenna conductors is found by solving the electrodynamic problem using the integral equation method. In this case, the antenna is represented as a system of conductors arranged in a certain way and oriented in space.

The methodology for calculating EMF levels provides for:

- the possibility of taking into account the underlying surface based on the two-beam model of radio wave propagation under the assumption that the underlying surface does not affect the current distribution in the antenna conductors;

- the possibility of taking into account the influence of metal structures based on the determination of the current induced on them by the antenna field.

The initial data for calculating the EMF levels are the geometric parameters of the antenna in the form of a set of coordinates of the ends of the conductors, the geometric and electrical parameters of the underlying surface, and the technical characteristics of the radio transmitting means.

Appendix 3 provides information on the recommended software, which includes the calculation of EMF levels according to the methods set out in the guidelines for the specified technical means.

The measurement technique is based on the principles laid down in the calculation forecast and is focused on the use of existing measuring instruments that provide sufficient accuracy in monitoring EMF levels.

2. Main provisions of the method of computational forecasting of electromagnetic field levels

2.1. Method Essence

The calculation of EMF levels directly from the antenna current is performed in two stages: first, the current distribution in the antenna conductors is calculated, then the EMF levels are calculated. The current distribution is calculated based on the solution of the corresponding electrodynamic problem by the integral equation method in the thin-wire approximation. In this case, the actual design of the antenna is represented as a system of electrically thin cylindrical conductors. The solution of the integral equation is performed by the collocation method with a piecewise sinusoidal basis. The calculation of EMF levels is performed directly from the found current distribution, taking into account the presence of aperture distortions and reactive fields.

Calculation of EMF levels from the calculated RP is performed in three stages: first, the current distribution in the antenna conductors is calculated, then - RP and directivity factor (DRC), at the final stage, EMF levels are calculated from the found RP and DPC. The current distribution in the conductors is determined in the same way as when calculating the EMF levels directly from the antenna current.

Calculation of EMF levels according to passport RPs is performed in one stage. In this case, it is considered that the radiation (with a given directivity determined by passport RPs) comes from a point taken as the phase center of the antenna.

In the further presentation, unless otherwise stated, the units of measurement of all quantities are given in the SI system.

2.2. Calculation of current distribution in antenna conductors

The calculation of the current distribution in the antenna conductors is performed in the following sequence:

- building an electrodynamic model of the antenna;

- calculation of matrix elements of the system of linear algebraic equations (SLAE) - an algebraic analogue of the original integral equation;

- solution of the SLAE and determination of the expansion coefficients of the desired current distribution function (current function) according to a given basis.

Building an electrodynamic model

The real design is represented as a system of electrically thin rectilinear cylindrical conductors. The radius of the conductors in this case should not exceed (hereinafter - the wavelength). Larger radius conductors are represented as wire cylinders. Solid metal surfaces are represented as wire meshes. Conductors whose axes are smooth curves are represented as broken lines.

A spatial contour is introduced, formed by a set of axes of conductors. The positive direction of the circuit bypass is determined (it is also the positive direction for the current), and the curvilinear coordinate is entered, counted along it.

To determine the piecewise sinusoidal basis functions, each rectilinear conductor is divided into electrically short partially intersecting segments - segments. Each -segment is defined by three points: start , middle , and end (according to the chosen positive direction). In this case, the starting point of the -th segment (if it is not the first on this conductor) coincides with the midpoint of the -th, the end (if it is not the last on this conductor) - with the midpoint of the -th: , . If the i-th segment is the first (last) on the given conductor, then its start (end) point coincides with the beginning (end) of the conductor.

The points that define some th segment are associated with 3 radius vectors , , (initial, middle and end points, respectively), as well as the radius vector of the collocation point - a point on the surface of the conductor closest to the point .

Straight conductors are divided into segments uniformly. In this case, the segment length should be chosen from the condition:

conductor radius.

With an increase in the length of the segment relative to the specified limits, the approximation error increases, with a decrease, the conditionality of the SLAE worsens, as a result of which the computational algorithm may turn out to be unstable.

Additional segments are introduced to describe the branching of conductors. In this case, the midpoint of the additional segment coincides with the extreme points of the connecting conductors, and the initial and final points coincide with the midpoints of the extreme (nearest) segments on these conductors. In this case, in order to avoid the appearance of linearly dependent SLAE equations, the following rules must be observed:

- the number of coplanar conductors connected at one point should be no more than 3 (2 additional segments are introduced);

- the number of non-coplanar conductors connected at one point should be no more than 4 (3 additional segments are introduced).

If it is necessary to describe the electrical connection of a larger number of conductors, the points of electrical contacts should be separated in space by an electrically small distance, which is not essential for the electrical characteristics of the antenna.

When modeling a solid surface with a wire mesh, no additional segments are introduced at the mesh nodes.

The gaps of active vibrators (to which supply voltages are supplied) are also described by segments. In this case, the midpoint of the segment coincides with the midpoint of the gap, and the initial and final points coincide with the midpoints of the extreme (nearest) segments on the conductors adjacent to the gap (shoulders of the vibrator).

Calculation of the SLAE matrix

The SLAE matrix (extended) contains a square matrix ( - the total number of segments in the model) with elements () and - a dimensional column of free members (). Here - matrix row number (SLAE equation number, collocation point number), - matrix column number (segment number).

The element of the square matrix is ​​numerically equal to the tangential component of the electric field, taken with the opposite sign, created by the -th segment with a unit current at the midpoint of the -th segment. The value is defined as the sum of two components:

Component corresponding to the radiation of the segment [, ];

- component corresponding to the radiation of the segment [, ].

The components and are calculated by the formula:

Ort in the cylindrical system associated with the -th segment;


- -ort in the cylindrical system associated with the segment [, ] ("-" sign) or the segment [, ] ("+" sign) of the th segment;

- applicate of the -th collocation point in the cylindrical system, associated with the segment [, ] ("-" sign) or the segment [, ] ("+" sign) of the th segment;

, - Green's function values ​​for different pairs of points;

- distances between the -th collocation point and the extreme (initial and final) points of the -th segment;

is the distance between the -th collocation point and the midpoint of the -th segment;

- wave number.

The free members of the SLAE are defined as follows.

If the -th collocation point corresponds to the segment located on the conductor, then . If the -th collocation point corresponds to a segment located in the gap of the active vibrator, then the normalized value of the input voltage is taken as the value. In this case, if the antenna contains one vibrator, then the normalized input voltage is assumed to be equal to one. If the antenna contains two or more vibrators (antenna array), for one of the vibrators, the normalized input voltage is assumed to be equal to unity, and the remaining input voltages are normalized to the actual value of the input voltage of this vibrator.

The SLAE solution is recommended to be performed by the optimal elimination method.

SLAE is written as follows:

As a result of solving the SLAE, the expansion coefficients of the desired current function , , ... are determined. Numerically, these coefficients are equal to the currents at the midpoints of the corresponding segments for the chosen normalization of the input voltages (currents).

2.3. Calculation of electromagnetic field levels

2.3.1. General provisions

Additional criteria are introduced to select the method for calculating EMF levels.

At , the EMF level must be calculated directly from the antenna current, and at , according to the RP calculated from the antenna current or the passport RP, where:

Distance from the geometric center of the antenna to the observation point (where the EMF level is determined);

- the maximum size of the antenna.

If there is no information about the device (construction) of the antenna (i.e. it is not possible to build an electrodynamic model and calculate the antenna current), but its nameplate RPs are known, the EMF levels are calculated using the passport RPs. In this case, if the obtained values ​​of the field strength (electric and magnetic) must be multiplied by the correction factor , the graph of which, depending on the parameter, is shown in Fig.1.

The criterion for the need to take into account the influence of metal structures is the fulfillment of the inequality:

The distance from the observation point to the point closest to it on the metal structure.

- the maximum size of the metal structure, measured vertically with vertical polarization and horizontally with horizontal polarization;

- the maximum size of the metal structure, measured horizontally with vertical polarization and vertically with horizontal polarization;

, - coefficients, the values ​​of which are determined by the graphs in Fig.2.

The influence of the underlying surface is not taken into account in the following cases:

- the observation point is located below the level of the underlying surface (here we mean surfaces of limited dimensions, for example, the roofs of buildings);

- the height of the antenna center and the height of the observation point relative to the underlying surface is 10 or more times greater than the distance between the antenna center and the observation point.

Radiated power is determined as follows.

For antenna-feeder devices of FM broadcasting and base stations of land mobile radio communications, the value is determined by the formula.