Thermal effects of electromagnetic origin from heating processes to biological disturbances due to field exposure—A review

Abstract

This contribution aims to appraise, analyze and evaluate the literature relating to the interaction of electromagnetic fields (EMF) with matter and the resulting thermal effects. This relates to the wanted thermal effects via the application of fields as well as those uninvited resulting from exposure to the field. In the paper, the most popular EMF heating technologies are analyzed. This involves on the one hand high frequency induction heating (HFIH) and on the other hand microwave heating (MWH), including microwave ovens and hyperthermia medical treatment. Then, the problem of EMF exposure is examined and the resulting biological thermal effects are illuminated. Thus, the two most common cases of wireless EMF devices, namely digital communication tools and inductive power transfer appliances are analyzed and evaluated. The last part of the paper concerns the determination of the different thermal effects, which are studied and discussed, by considering the governing EMF and heat transfer (or bio heat) equations and their solution methodologies.

Intentional and Undesirable Effects Related to the Interaction of Electromagnetic Fields with Major Living Tissues

“…These unwanted exposures can affect the exposed materials by disrupting their normal functioning [9,17]. In the case of living tissues, RF EMF exposures would create unwanted thermal BEs [10]. As we see, the effects of EMF exposures might be desired in one case but undesirable in the other.…”

“…The connections between EMFs and humans in these activities certainly play an important role in human well-being. In addition to these desired dealings, there are undesirable effects on human tissues as well as those of fauna and flora [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. These EMF exposures are due to two types of sources, near field (NF) as telephone cells [9], and far field (FF) as antenna towers for telephone cells [7,8].…”

“…These two types of exposure can produce biological effects (BEs) on the various exposed tissues of humans, fauna and flora. These BEs are related to induced fields in tissues and generally result in thermal effects depending on the characteristics of the EMF source, the features of the exposed material, and the conditions and duration of exposure [9,10]. The higher the Disclaimer/Publisher's Note: The statements, opinions, and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s).…”

“…field strength and frequency are in the tissue and the longer the exposure interval, the greater the temperature rise will be. Such BEs can be desired as in healthcare hyperthermia treatments or microwave cooking [10]. Otherwise, BEs due to unwanted exposures are generally harmful and need to be supervised.…”

“…These are denoted by the specific absorption rate (SAR) and temperature rise ΔT. The 3D distributions of these quantities obtained from the coupled solution of the EMF and the BH equations should be checked with thresholds to insure the tissues security [9,10,17]. These thresholds depend on, the tissue part of body or plant, the relation with exposure source, and the exposure conditions.…”