Utilization Investigation On Modeling Aperture And High-Q Enclosure Using FDTD

With the development of wireless telecommunication technology, the available frequency spectral becomes more and more crowded, the electromagnetic environment is getting worse, then electromagnetic compatibility (EMC) problem gains much more esteem than before. In the research, prediction of EMC is very useful. At the same time, rigorous analytic solutions become unpractical because of the complication of system, devices and facilities nowadays. Therefore, numeral methods of electromagnetic become a widely used tool in prediction of EMC. Among these numeral methods, the finite-difference time-domain method becomes more and more popular because of its unique features.To solving EMC problems, shielding, filtering, and grounding are used a lot in engineering. For many devices and facilities, shielding boxes and enclosures are required to insulate the EM interference. In these years, because of the demand of miniature of system, a number of devices should be settled in tiny and closed spaces, and sometimes shielding boxes are taped in PCB. The utilization of shielding enclosures are paid more and more attention.In the process of shielding enclosure design, on must consider the difference of shielding enclosure dimension and configuration, and other special structure such as slots, apertures, windows and wires. Only tests are used, without convenient analyzing methods or simulation tools. In case of a fail design, remediation or redesign should be done. That would be unstable and undependable, which will overextend the period, increase the cost of design. There are also some experimental principles, but no quantitative results. Therefore, an auxiliary tool is required urgently.The normal FDTD have some difficulties in modeling shielding enclosures. Aiming at modeling the enclosure efficiently, the thesis makes a deep study on the slot model and high-Q model. A number of thin-slot formalisms (TSF) are fulfilled on the 3-D infinite PEC plane model for comparison. The effectivities and precisions are also analyzed. Furthermore, the window method of digital signal processing are introduced in the simulation of high-Q enclosure, cutting off the time array to do the FFT accurately. The previous methods are used to simulate different designs of shielding enclosures, and diagrams of shielding effectiveness vs. frequency are given. The simulation results have reference value for shielding enclosure design.