Bartlomiej Zubrzak

A New Method For Automated Noise Cancellation In Electromagnetic Field Measurement

Abstract Electromagnetic field (EMF) measurements have limited accuracy, which is additionally impaired by meter self-noise influence. In this paper, a novel noise cancellation method is proposed, based on the Hidden Markov Model (HMM) methodology. It allows us to calculate the overall field intensity with a much higher accuracy than that obtained from other popular approaches, especially when EMF measurements are close to the noise level. The effectiveness of the new method is illustrated on two EMF datasets, one recorded in an urban and the other in a rural area. Its performance is further evaluated in a thorough simulation study using datasets representing the two distinct noisy environments.

Methods of the electromagnetic fields intensity level assessment and monitoring in the environment

The paper contains review of electromagnetic field (EMF) sources from the environmental point of view. It shows the simplest methods of EMF measurement and differences between selective and broadband measurements listing its advantages and disadvantages, what is essential for the EMF assessment for the need of monitoring in the environment. The measurement possibilities are also one of the subject taken up in this work. Authors point an important aspect of EMF evaluation which is field intensity changeability in time (periodicity) characteristic for mobile telephony systems related with the subscribers daily activity.

A prototype of pulse electromagnetic field standard setup with envelope shaping

Paper presents a concept of pulse electromagnetic field (PEMF) standard setup with envelope shaping. Analysis of EMF sources with particular pulse envelopes is performed. Authors presented novel approach to build standard setup, that allow to shape envelope of generated PEMF. A prototype and principal of operation was described, two methods of envelope data handling presented and also a preliminary results of prototype testing.

Optimization of measurement methods for a multi-frequency electromagnetic field from mobile phone base station using broadband EMF meter

BACKGROUND This paper presents the characteristics of the mobile phone base station (BS) as an electromagnetic field (EMF) source. The most common system configurations with their construction are described. The parameters of radiated EMF in the context of the access to methods and other parameters of the radio transmission are discussed. Attention was also paid to antennas that are used in this technology. MATERIAL AND METHODS The influence of individual components of a multi-frequency EMF, most commonly found in the BS surroundings, on the resultant EMF strength value indicated by popular broadband EMF meters was analyzed. The examples of metrological characteristics of the most common EMF probes and 2 measurement scenarios of the multisystem base station, with and without microwave relays, are shown. RESULTS The presented method for measuring the multi-frequency EMF using 2 broadband probes allows for the significant minimization of measurement uncertainty. Equations and formulas that can be used to calculate the actual EMF intensity from multi-frequency sources are shown. They have been verified in the laboratory conditions on a specific standard setup as well as in real conditions in a survey of the existing base station with microwave relays. CONCLUSIONS Presented measurement methodology of multi-frequency EMF from BS with microwave relays, validated both in laboratory and real conditions. It has been proven that the described measurement methodology is the optimal approach to the evaluation of EMF exposure in BS surrounding. Alternative approaches with much greater uncertainty (precaution method) or more complex measuring procedure (sources exclusion method) are also presented).

Mitigation measures of electromagnetic field exposurein the vicinity of high frequency welders

BACKGROUND Presented information about the welding process and equipment, focusing on the emission of electromagnetic field (EMF) with levels significant in terms of the labor safety regulations in force in Poland - the ordinances of the Minister of Family, Labour and Social Policy that came into force on June 27, 2016 and June 29, 2016 - emerged due to harmonization with European Union directive 2013/35/EU of 26 June 2013 of the European Parliament and the Council. They presented methods of determination of the EMF distribution in the welding machine surroundings and analyzed the background knowledge from the available literature. MATERIAL AND METHODS The subject of the analysis included popular high frequency welders widely used in the industry. Electromagnetic field measurements were performed in the welder operating place (in situ) during machine normal operations, using measurement methods accordant with labor safety regulations in force in Poland and according to the same guidelines, the EMF distributions and parameters having been described. RESULTS They presented various scenarios of particular, real examples of excessive exposure to EMF in the dielectric welder surroundings and showed solutions, ranging from simple and costless and ending on dedicated electromagnetic shielding systems, which allowed to reduce EMF exposure in some cases of more than 80% (protection zone ranges) or eliminate dangerous zone presence. CONCLUSIONS It has shown that in the dielectric welders surrounding, significant EMF strength levels may be the result of errors or omissions which often occur during development, installation, operation or modification of welding machines. It has allowed to present the measures that may significantly reduce the exposure to EMF of workers in the welder surroundings. The role of accredited laboratories in helping in such cases was underlined. Med Pr 2017;68(6):693-703.

Alternative method of electromagnetic absorbers quality determination

Work presents basic information about electromagnetic absorbers, its parameters and known methods of its determination - calculations and direct measurement methods. A new simplified and cost-effective method of quality determination is presented, which introduce new quality measure - “Homogeneity Disorder Factor” (HDF). It bounds information about reflectivity with distance from measured absorber on particular frequency. Proper measurements are performed according to presented method and results are presented and discussed.

Electromagnetic field in high frequency welder surroundings

Paper describes the character of electromagnetic field (EMF) distribution in high frequency welder surrounding based on measurements performed for various welding scenarios, depending on material type, layer count and welding parameters. Measurement results were presented, visualized and discussed. Welding process and its parameters were described and also brief description of high frequency welder construction and operation principal was delivered.

GSM/UMTS base station as a unusual electromagnetic field source — Measuremenets in environment for LOS and NLOS scenarios

In this paper authors describe the nature of electromagnetic field (EMF) in surrounding of a base stations (BS) - working in GSM900/GSM1800 and UMTS systems. Multi-frequency fields, pulse field and EMF variability in time are the main difficulties, which are emphasized in this study. Additionally, long term monitoring measurement from different locations in Wroclaw (Poland) are presented. Measurement has been carried out using EMF selective and broadband meters in urbanized area. EMF changeability trends were determined in measured period for GSM900/1800 and UMTS bands and two different locations for both, LOS and NLOS cases.

Electromagnetic fields from mobile phone base station – variability analysis

Abstract The article describes the character of electromagnetic field (EMF) in mobile phone base station (BS) surroundings and its variability in time with an emphasis on the measurement difficulties related to its pulse and multi-frequency nature. Work also presents long-term monitoring measurements performed recently in different locations in Poland – small city with dispersed building development and in major polish city – dense urban area. Authors tried to determine the trends in changing of EMF spectrum analyzing daily changes of measured EMF levels in those locations. Research was performed using selective electromagnetic meters and also EMF meter with spectrum analysis.