Field strengths and specific absorption rates in automotive environments

Both densitometric and dosimetric methods were used to measure human exposure in the near fields inside cars, generated by high power transceivers (30-120 W) with a VHF or a UHF antenna mounted on the trunk. A back half and a full car were used for the tests. The densitometric readings of apparent power density given by the far field survey probes show relative field strengths such as standing wave patterns inside the cars, and thus are called equivalent plane wave power densities. Results from these measurements show that the E and H field intensities exceed the FCC´s safety limits. An electric field probe mounted on a robot arm was used for dosimetric measurement of specific absorption rate (SAR) in a sitting position liquid human phantom. The dosimetric measurements show that even though the apparent power densities measured in the car exceeded the FCC´s limits, SAR in simulated human tissue do meet the FCC´s basic safety limits