DESIGN AND VALIDATION OF A TEM CELL USED FOR RADIOFREQUENCY DOSIMETRIC STUDIES

A Transverse Electromagnetic Mode (TEM) cell is an interesting option for studying the biological efiects 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 efiect. Unfortunately, experimental dosimetry is often unavailable or inapplicable, so that a pre- characterized 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 100MHz{1GHz frequency range. Validation is achieved by comparing the computed vs. measured values for three signiflcant parameters: scattering parameters, incident electric fleld distribution, and absorbed power in a set of liquid samples. Successful validation and characterization is achieved by using CST Microwave Studio's flnite integration technique (FIT), and respectively a network analyzer for the experimental setup. The secondary objective is a dosimetric study of four difierent liquid samples loaded in the cell. The absorption coe-cient (AC) is used, assimilated to the speciflc absorption rate (SAR) of energy deposition in the entire sample volume. AC is shown to converge in experiment and simulation up to 800MHz for all samples. AC doesn't depend directly on the samples' volume (despite greater volumes frequently showing higher absorption) but rather upon the internal fleld distribution, which in turn mostly depends on the frequency and on the dimensions of the liquid samples.