Design and Validation of a Tem Cell Used for Radiofrequency Dosimetric Studies

Abstract

Abstract-A Transverse Electromagnetic Mode (TEM) cell is an interesting option for studying the biological effects of radiofrequency radiation at reduced scale (in vitro studies).Controlled and well-characterized exposure conditions are essential for a conclusive investigation: the biological sample is exposed to a uniform incident electromagnetic wave and the dose of absorbed radiation is precisely determined and correlated with the effect. Unfortunately, experimental dosimetry is often unavailable or inapplicable, so that a precharacterized and validated experimental setup is most valuable. As such, the primary objective of the present work is to experimentally validate a computational model of a self-built TEM cell designed for bioelectromagnetic experiments in the 100 MHz-1 GHz frequency range. Validation is achieved by comparing the computed vs. measured values for three significant parameters: scattering parameters, incident electric field distribution, and absorbed power in a set of liquid samples. Successful validation and characterization is achieved by using CST Microwave Studio's finite integration technique (FIT), and respectively a network analyzer for the experimental setup. The secondary objective is a dosimetric study of four different liquid samples loaded in the cell. The absorption coefficient (AC) is used, assimilated to the specific absorption rate (SAR) of energy deposition in the entire sample volume. AC is shown to converge in experiment and simulation up to 800 MHz for all samples. AC doesn't depend directly on the samples' volume (despite greater volumes frequently showing higher absorption) but rather upon the internal field distribution, which in turn mostly depends on the frequency and on the dimensions of the liquid samples.

Low-dose 1GHz exposure in controlled conditions for the study of cellular effects of in vitro irradiated blood

“…For the experimental SAR determination, we used a formula connecting the absorbed power (P a ) with the input power P in [19]: (1) where S 11 is the input port voltage reflection coefficient and S 21 is the forward voltage gain coefficient. These scattering parameters were experimentally measured in two cases: 1) in the case when the TEM cell was unloaded by the blood samples (the absorption was due to the cell walls, ferrite tiles, radio-absorbing material and empty containers of the blood samples); 2) in the second case when the cell was loaded by the blood samples.…”

Numerical and experimental analysis of transverse electromagnetic cell

“…Conductor thickness is chosen as 2 mm again. TE mode cutoff frequencies can be calculated easily and new operating frequency range will be between 1 and 2 GHz with new TEM Cell dimensions. When all these modifications are applied to draw all half TEM Cell, simulation results are shown in Figures and .…”

“…Return loss of TEM Cell created using [2]. to be chosen carefully since there is too much loss between the probes.…”

Electromagnetic Analysis of an Aperture Modified Tem Cell Including an Ito Layer for Real-Time Observation of Biological Cells Exposed to Microwaves

“…For in vitro studies of RF-induced biological effects at reduced scale, the Transverse Electromagnetic (TEM) cell is a commonly used delivery device [12][13][14][15][16]. An opened TEM cell with an aperture in the center of the lower plate has been proposed for real-time microscopic observation of exposed cells [17].…”