This example shows the ability of XFdtd^® to import complicated CAD files, mesh them, and produce accurate results.

This example shows the ability of XFdtd to import complicated CAD files, mesh them, and produce accurate results. The antenna is the reference dipole used for SAR system validation as described in IEEE Standard 1528, Recommended Practices for Determining SAR. The antenna is described in Section G.1. The antenna is a half-wave dipole with a quarter-wave coaxial balun. The impedance is to be calculated including the effects of the near field coupling with a nearby flat phantom composed of a thin lossless dielectric container holding a lossy dielectric liquid. A CAD file for the antenna is directly imported into XFdtd and is shown in solid view in Figure 1. Figure 2 shows an XFdtd display of the feed point location (bright green line) offset to the left and along the coaxial center conductor. The antenna and flat phantom geometry is meshed in XFdtd and the calculation is excited with a Gaussian pulse. The transient feed port voltage and current determine the input impedance versus frequency. The steady state magnetic and electric fields are displayed in Figures 3 and 4, and a frequency domain plot of antenna impedance and return loss (RL) is shown in Figure 5. ARPEL Laboratory measurements at 5.8 GHz provided an impedance of 56 – j17.7 Ohms, return loss -15.3 dB, which corresponds well with the XFdtd results in Figure 5. Antenna CAD file provided by APREL Laboratories, analysis provided by Daniel Brooks of APREL Laboratories, http://www.aprel.com.