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

Abstract

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 New Method For Automated Noise Cancellation In Electromagnetic Field Measurement

“…A much lower detection threshold and significantly greater dynamics can be reached using the selective measurement technique preferred in EMF exposure measurements at GSM base stations [1,12]. It is recommended to use in such systems specially designed multiband [5] or wideband antennas [8], which allow to obtain sensitivity at the level of a single mV/m with dynamics up to 140 dB, and to apply bandpass filters to minimize noise influence [9].…”

A prototype of pulse electromagnetic field standard setup with envelope shaping

“…The basic concept of the PEMF with envelope shaping standard setup is presented in figure 1 and was also mentioned in [1]. It consist of signal generator, digital step attenuator (DSA) section with control module, power amplifier and antenna.…”

“…In addition, the majority of common broadband EMF meters used for the exposure assessment for the purpose of environmental protection or labor health and safety is designed for measuring constant monochromatic EMF [1]. When measuring pulse electromagnetic field (PEMF) with such device, significant errors may occur, what authors already show in [2].…”

A critical note to the standard procedure for assessing exposure to GSM electromagnetic field

“…Generally speaking, the extrapolated value can be considered only as an upper bound for the exposure. Additionally, extrapolation may be challenging and affected by large uncertainties for GSM, UMTS and LTE system because of the large variability of the electric field due to traffic and propagation conditions [8][9][10]. Focusing on the GSM system, which is still the most widespread cellular system worldwide, the extrapolation suggested in the EN 50492 standard [11] requires measurement of the electric field at the BCCH (Broadcast Control CHannel) frequency, which is always transmitted at the maximum power, multiplied by the square root of the total number of carrier frequencies of the same BTS (Base Tranceiver Station).…”