Biological and sanitary effects of high power microwave ultra wide band (HPM/UWB) signals

摘要

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 based, in particular, on t- e 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.