FDTD Simulation of Handset Performance



  Finite difference time domain (FDTD) computations is a numerical technique for determining the fields emanating from e.g. a handset. The tool allows easy experimentation with handset designs and is a practical method for investigation of, e.g., the influence of the position of the user's hand on the handset. The paper [Graffin et al, 2000 (a)] reports on measurements in the anechoic chamber of two antenna types with and without a phantom head and hand, in addition to the results of FDTD computations based on a model of the same phantom and handsets, see CPK Annual Report 2000 - Figure 4.5.9 (Model phantom head and hand and associated FDTD model). The E-fields obtained from the simulations and the measurements were found to match surprisingly well, and hence it was verified that the FDTD computations can be used in place of measurements in the anechoic chamber. The losses introduced by the phantom head and hand found for the two methods typically differed by less than one dB. Using the FDTD tool it was found that for the monopole antenna the phantom alone introduces a loss of 5-6 dB. The phantom hand adds another 1-6 dB, depending on the position of the hand on the handset. For the patch antenna the phantom alone only introduces about 1.6 dB of loss with an additional 3-6 dB when the phantom hand is included. Regarding the tilt angle of the handset, a variation of 2.5 dB was noted for the monopole antenna whereas the path antenna was less sensitive with a 0.8 dB variation. (Gert F. Pedersen)
Effektiv start/slut dato31/12/200331/12/2003