Medical Shelter EMC Design And Simulation Based On FEKO System Simulation Software

Medical shelter is mobile medical platform under field conditions. In order to improve the level of information technology and treatment capacity in the future war, the medical shelter has integrated many information system such as information management systems, video surveillance systems, telemedicine systems, and communication and command systems. These systems incorporate a large number of electronic devices. Some electronic devices are the interference sources, which radiated electromagnetic energy to the outside world through the slits and openings, causing the more complex electromagnetic signals in the shelter and making the subsystems prone to mutual coupling electromagnetic interference(EMI). However, some devices are sensitive equipment. The functions and data in those devices maybe distorted or damaged under the EMI and cannot be the reliable medical diagnosis credentials, confusing the diagnosis by the doctor and playing a direct impact on the safety of the patients.Since the medical shelter is used in the field, and often expand in the open spaces, making it vulnerable to the nature lightning. Intense lightning electromagnetic pulse(EMP) will cause instantaneous interference. Furthermore, it can burning the sensitive devices to cause equipment failure. Meanwhile, a large number of electronic information equipment are used on the information battlefield. These devices are of institutional complexity, species diversity, and strong power, causing a very complex external electromagnetic environment. In particular, the electromagnetic bombs, a type of non-conventional weapon, the high-intensity EMP not only damage the communication and command system that allows communication interruption, but also to destroy the computer network system, and even invade some highly sensitive medical equipment through electromagnetic waves, or burn a semiconductor integrated circuit electronic devices, making the device paralyzed or completely destroyed, and the contact device may damage the wounded, greatly affecting the battlefield rescue and severely weakening the ability of medical support.In the original design process of the medical shelter, a few electronic equipment cannot highlight the influence of the electromagnetic compatibility(EMC). Those minor problems about EMC appear in the system test can be solved through some technical means. EMC has not attract enough attention due to this factor. With the increasing electronic equipment, the EMI problem has been becoming more and more prominent. The researchers have started to study EMC and do some simple design. However, the general requirements of the development and research tasks in the indicators book for EMC is not clear, the problem of irrational prominent indicators, the development of demonstration stage, technical design, engineering and manufacturing stages failed to carry out thorough EMC design of a system, the experimental results can’t reach the expected requirements duo to the lack of the effectiveness verification through forecast and simulation. The EMC of the medical shelter need to be redesigned, which led to the waste of time, manpower, material and financial resources. In conclusion, it can cause unreasonable EMC design without the prediction simulation.To this end, the main research includes the EMC design and simulation of electromagnetic coupling on the medical shelter. We provided a comprehensive study on the shielding and simulation technology of EMC. Then we did a detailed study of the electromagnetic properties on three aspects, i.e., interference source, coupling path and sensitive equipment, in the medical shelter using the prediction and simulation technology. The main contents are as follows:The interference sources were analyzed and did the electronic equipment classification according to the harmful extent to system performance and our tasks. And those interference sources affecting the electromagnetic environment in the medical shelter, e.g., power equipment, information system cabinet, a communication antenna system, are found in our study. We used different technical measures for different interference sources. For power equipment, we used the shielding technology to protect other equipment from interference. For information system cabinet, we used the grounding techniques to avoid mutual interference between the lines. For a communication antenna system, the filtering technique was used to filter out those unwanted signals in the feeder.Then, the effect of metal thickness was illustrated and the frequency of the radiation on the shielding technology by analyzing the shielding properties of infinite metal plate to the plane wave using the electromagnetic shielding numerical model. From a low frequency to a certain frequency, making the shield thickness equal to the skin depth, the shielding is a constant. With the further increasing frequency, attenuation performance of the shielding technology increases exponentially. The high-frequency apertures leakage model was used in our study to simulate the shielding effectiveness about the slotted chassis. The criterion were proposed in the EMC shielding design which demand suitable shielding materials, minimize the number of openings and open area, and to ensure electrical continuity of the shelter cabin and the connections between devices.Meanwhile, the coupling situation had analyzed between the source in the opposite direction of the public and the receiver circuit using the electromagnetic interference model caused by the common loop. The analysis of changes in their coupling current had been analyzed by changing the distance between the two cables using EMC simulation and we demand the reasonable laying with distinguishing the role of those different lines and all kinds of cables must be insulated from each other during EMC grounding design.Furthermore, the apertures leak was simulated as a slit aperture antenna far-field diffraction vector zone using the high-frequency radiation leakage apertures model. And the opening size was adjusted in the ventilation waveguide window as well as the door according to the simulation result about shielding effectiveness, making it can reach pre-design requirements in medical shelter.Our main contribution is the first introduction with the EMC prediction and simulation technique to the medical shelter. The in-depth analysis was did about the electromagnetic environmental conditions in the medical shelter and established the numerical analysis of the low frequency electromagnetic field coupled model and high frequency apertures leakage model. Simulation and experimental data was compared by the electromagnetic simulation software,establishment of medical shelter simulation model library. In the initial stages of EMC design, the prediction simulation technology was used to analyze the EMC situation about the whole medical shelter to solve or reduce the electromagnetic interference problem in the practical applications.