Three-dimensional FDTD analysis of complicated antennas

We treat with a monopole antenna mounted on a conducting box modeling a portable telephone. Two different source excitation methods and corresponding FDTD results are discussed. The same antenna in which the rectangular conducting box is covered with a layer of lossy dielectric modeling a plastic cover is analyzed to simulate the practical use of the portable telephone. The FDTD analysis is carried out for the model where the antenna is covered with a rectangular lossy dielectric, modeling a human head, is located close to a lossy multilayered sphere modeling a human head. The SAR of the head is also calculated. The built-in antennas on a conducting box, as examples of very complicated antennas are examined. The antenna is small compared to a wavelength, and is matched to 50 ohm resistance by a short pin. The transient response for this structure is found to contain a DC-like current component of a long period. To eliminate this difficulty, a voltage source with a series resistance (matched generator source) is introduced. Finally, a full-wave analysis of the subsurface radar antenna is performed by using the FDTD method