Exploration of Whole Human Body and UWB Radiation Interaction by Efficient and Accurate Two-Debye-Pole Tissue Models
We have developed a computationally efficient finite-difference time-domain (FDTD) model of a whole human body based on accurate 2-pole Debye dispersion dielectric tissue properties. Comprehensive FDTD analyses of the interaction between a whole human body and ultrawideband (UWB) radiation are carried out by including the proposed frequency dependent tissue models. The 2-pole Debye models have been obtained for 50 individual human tissues from Gabriel's Cole-Cole data by the least squares fitting technique over the frequency range from 100 MHz to 6 GHz. A whole human body composed of the 2-pole Debye models is exposed to spread spectrum radiation. Local energy absorption in a human body is compared between the proposed model and the conventional model of frequency-independent permittivity and conductivity. Resonance states are then investigated in the human body exposed to electromagnetic nano-second pulse radiation. For the extraction of the frequency contents from the highly damped FDTD time signals, a spectrum analysis technique based on an auto-regressive (AR) model has been applied. Pulse propagation in the vicinity of the human body is also characterized by the proposed model for the wireless body area network (WBAN) application that has been proposed recently for computer assisted medical diagnostics and rehabilitation.
Available from: Thérèse Schunck
- "Consequently, the HPM/UWB pulse energy dissipation in the tissues also depends on the pulse frequency spectrum and on the frequency dependence of the dielectric properties of the exposed biological material. In the case of the human body or eye    , when an HPM/UWB pulse interacts with biological matter, the lowest frequencies penetrate deeply, whereas high frequencies are absorbed close to the surface. Moreover, biological samples can also act like dielectric resonators and thus have resonance frequencies which depend on their size, shape and dielectric properties. "
[Show abstract] [Hide abstract]
ABSTRACT: form only given. Systems emitting High Power Microwave Ultra Wide Band (HPM/UWB) pulses are developed for both military and civilian applications. The knowledge of the biological effects of this type of radiation is crucial for the protection of the staffs involved in UWB system development but also within the framework of their future uses. As no exposure standard exists, the French-German Research Institute of Saint-Louis has initiated a research program in this area. This program was constituted firstly by a bibliographical survey on the damage mechanisms, the dosimetry and the biological effects. At the sight of the results, it has been considered necessary to measure HPM/UWB pulse propagation in tissue-mimicking phantom materials as mainly numerical works were done on this topic. Indeed the question of the electromagnetic field amplitude in biological tissues and of the loss of energy along its propagation is crucial for the determination of damage mechanisms that can be expected. In this purpose, D-dot probes were used to measure the electric displacement field and set into materials that possess the dispersive dielectric properties of human soft tissues over the microwave frequency range, from 100 MHz to 3 GHz. Cubes of phantom materials containing D-dot were exposed to HPM/UWB pulses which have the following characteristics: a sub-nanosecond rise time, an electric field amplitude of 350 kV m-1 and a pulse duration of 3 ns. This paper will present the results of the bibliographical survey and of these experiments. Additionally, at our best knowledge, no studies dealing with the impact of HPM/UWB pulses on Active Implementable Medical Devices (AIMDs) were published. Consequently, this aspect has also been examined. Implementable Cardiac Pacemaker (ICP) was selected as AIMD since it is the most frequently implemented and it has to maintain vital functions. A bibliographic study was done to determine the in vitro experimental protocol. This latter was b- sed, in particular, on the work performed to establish standards for the exposure of people bearing AIMDs to electromagnetic fields, on studies in the context of EMP simulator and also on studies achieved for UHF frequency range. The effects of HPM/UWB pulses on an ICP were investigated and both synchronous and asynchronous pacing modes were tested. The experimental results will also be presented.
[Show abstract] [Hide abstract]
ABSTRACT: In this paper the application of the Ultra Wideband technology in the medical field is investigated. This is done by presenting a mathematical description of the Ultra Wideband medical scenario and a model of the human body. Besides, the requirements of antennas for Ultra Wideband medical applications are discussed. The most important existing applications of the UWB technology in the medical field are shown and discussed.
[Show abstract] [Hide abstract]
ABSTRACT: Our goals consist in designing and realizing a Ultra Wide Band (UWB) radar for a medical application. On this basis, we study in this contribution the interaction between the radar's electromagnetic pulse and the human body layer in a UWB frequency range. Indeed, this study helps us to design this radar system and prove the possibility of taking an image of each human body layer by exploiting the several reflected echoes. In fact, we propose an analytic method that enables us to compute the reflected echo by the human body of an oblique incident radar pulse. This new method discards the mutual influence between two adjacent human body layers in order to retrieve a recursive expression that computes the total reflection and transmission coefficients by each human layer. Then, we induce the specific absorption rate of each human body structure. In the same vein, this result enables the designer to estimate the propagation medium of the human body. According to this study, we can realize a UWB radar in an attempt to capture an image of the intern human body structure and detect some dangerous infections like cancer.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.