RF energy in cars from window-mounted antennas

The measurements of the E-field energy density inside and around a car equipped with window-mounted antennas are reported. The 800 MHz window-mounted antennas produce inside a metal car energy densities comparable to those due to an antenna mounted in the center of the roof. In the 450 MHz band, window-mounted antennas support inside the vehicle energy densities about 2-4 times higher than those from center of the roof mounted antennas. At VHF, with the exception of few localized spots, the E field intensity in the car is less than 20 V/m (∼100 µW/cm²). These field levels are very similar to those found in previous tests by Motorola and the NBS (1) using center of the roof mounted antennas.