FDTD predictions and measurements of car effects on portable telephone received signal levels

In order to determine the signal attenuation that might be expected when using a portable telephone inside an automobile, the signal attenuation for a variety of incidence angles and antenna locations inside a car with one or two passengers was measured at 1920 MHz. In addition to the measurements, finite difference time domain (FDTD) calculations of the signal attenuation were also made. The FDTD calculations and measured signal attenuation were compared, and agreed well with one another. The FDTD predictions were then analyzed to provide statistical summaries of the signal attenuation characteristics for different incidence angles, number of passengers, windows up/down, and receiving antenna locations and orientations.