FDTD analysis of a gigahertz TEM cell for ultra-wideband pulse exposure studies of biological specimens

Abstract

Abstract-Gigahertz transverse electromagnetic (GTEM) transmission cells have been previously used to experimentally study exposure of biological cells to ultra-wideband (UWB), monopolar, electromagnetic pulses. Using finite-difference time-domain (FDTD) simulations we examine the time-dependent electric field waveforms and energy dose spatial distributions within a finite volume of biological cell culture medium during these experiments. The simulations show that when one or more flasks containing cell culture media are placed inside the GTEM cell, the uniform fields of the empty GTEM cell are significantly perturbed. The fields inside the cell culture medium, representing the fields to which the biological cells are exposed, are no longer monopolar and are spatially highly nonuniform. These effects result from a combination of refraction and distortion of the incident wave, combined with excitation of resonant eigenmodes within the cell culture medium volume. The simulations show that these distortions of the incident waveform may be mitigated by supporting the sample on a high permittivity pedestal and modifying the incident waveform to more closely approximate a Gaussian pulse. Under all simulated conditions, the estimated maximum temperature rises are completely negligible, ensuring that any experimentally observed unusual cell function or histopathology can be associated with nonthermal effects.Index Terms-Dosimetry, FDTD methods, gigahertz transverse electromagnetic (GTEM) cell, ultra-wideband (UWB) exposure.

A subnanosecond electric pulse exposure system for biological cells

“…Conventional exposure systems for studying the biological effects of short pulses are mostly based on a Transverse Electromagnetic (TEM) Cell [22], in which biological cells are contained in a flask. The average electric field for cells is thus rather low as the physical size of the systems is large.…”

Research on fast rise time EMP radiating-wave simulator

“…The traditional transmission HEMP simulator is based on transmission line such as parallel plate [2], GTEM cell [3] and TEM cell [4]; generate HEMP simulation wave similar to the excitation pulse in the transmission line. The rise time of the simulation pulse is restricted by the size of HEMP simulator, so that large type HEMP simulator can't produce fast rise time simulation electromagnetic pulse [5]. The large radiating-wave simulators were built in 1970s, for airplane and missile HEMP testing, such as Germany HPD and VPD [6] simulation system.…”

Electromagnetic and Thermal Analyses of Improved Gtem Cells for Bioelectromagnetic Experiments

“…For this aim, different exposure systems have been proposed for in vitro [1][2][3][4] and in vivo [5][6][7] dosimetric experiments exploiting different electromagnetic devices (e.g., resonant waveguides, Wire Patch Cells (WPC), Transverse Electromagnetic (TEM) cells) and also GHz Transverse Electromagnetic (GTEM) cells [8][9][10]. Further insight in the bioelectromagnetic problem is given by numerical models which analyze the whole body dosimetry [11][12][13], the electromagnetic and thermal effects of the irradiation of specific organs (e.g., the human eye or the brain) [14,15], the electromagnetic interaction at the cell membrane level [16] or the Specific Absorption Rate (SAR) distribution of in vitro cell cultures [17].…”