Analysis of Radiated Fields for the Design of a RJ45 Connector Using FDTD Method

The finite-difference time-domain (FDTD) method is successfully used to calculate the electric fields radiated from a prototype of a RJ45 connector for Ethernet transmission. Simulation results of the electric fields radiated from the prototype of this RJ45 connector are validated by measurement data for vertical and horizontal polarizations in 300 ~ 1000 MHz frequency range. It is also found that simulation and measurement results for both vertical and horizontal polarizations are over the regulation limit at 600 MHz. In order to meet regulation limits, further studies are also conducted by taking numerous possible affecting factors on radiated electric fields into consideration for FDTD simulations; these include the aperture area, the location of the excitation, the material used for the aperture, enclosures with and without grounding. From simulation results presented in this paper, it is found that the magnitude of the higher emission levels can be reduced by reducing the aperture area, putting the location of excitation deeper into the connector, using materials with smaller dielectric constants and conductivities for the aperture, and adding a grounding enclosure on the RJ45 connector.