Finite Difference-Time Domain Analysis of Electromagnetic Interference andRadiation Problems

摘要

The application of the finite difference-time domain (FD-TD) technique toproblems in electromagnetic interference and radiation is examined, and enhancements to the method in order to increase its accuracy and efficiency are considered. The primary motivation for studying electromagnetic radiation from various structures which compose a computer is that computers are now operating at faster speeds (i.e. 100's of MHz) and consuming more power resulting in significantly increased levels of power at higher frequencies. Three electromagnetic interference problems associated with computers are analyzed. First, electromagnetic radiation from VLSI heatsink configurations is examined. Next, electromagnetic emissions from modules-on-backplane configurations are analyzed. The third problem involves the analysis of coupling of electromagnetic energy by wires exiting from metallic enclosures. In addition to these interference problems, the effects of non-uniform substrates on radiation by microstrip patch antennas are studied. In particular the use of non-uniform substrates to reduce loss due to surface waves is examined. The electromagnetic radiation from a VLSI chip package and heatsink structure is analyzed using the finite difference-time domain technique. The dimensions of a typical configuration calls for a multi-zone gridding scheme in the FD-TD algorithm to accommodate fine grid cells in the vicinity of the heatsink and package cavity and sparse gridding in the remainder of the computational domain. The issues pertaining to the effects of the heatsink in influencing the overall radiating capacity of the configuration are addressed. Analyses are facilitated by using simplified heatsink models and by using dipole elements as sources of electromagnetic energy to model the VLSI chip.