IEC IEEE 62704-2-2017 pdf download.Determining the peak spatial-average specific absorption rate (SAR) in the human body from wireless communications devices, 30 MHz to 6 GHz – Part 2: Specific requirements for finite difference time domain (FDTD) modelling of exposure from vehicle mounted antennas.
5 Exposure configuration modelling
5.1 General considerations The three relevant elements that define the exposure conditions in vehicular environments are: the communication device(s) with antenna(s), the vehicle model, and the location of the exposed subject. The communication device or devices typically consist of one or more transceivers connected to a single antenna. The connection of multiple transceivers may require multiplexers and/or power combiners, in addition to the RF transmission line (e.g. section of coaxial cable) routed from the transceiver (or the combiner) to the antenna connector. The term “transceiver” in the following refers to a single transceiver or a more complex system comprising an arbitrary number of transceivers and combiners, and possibly other devices along the RF signal path. Conventionally, any components inserted before the cable (if any) leading to the antenna will be considered part of the transceiver. The transceiver features an RF port (typically the connector where the cable is attached). The relevant RF signal characteristics (frequency, bandwidth, average power) at this port shall be known. Relevant features of the antenna(s) are the geometrical dimensions, physical construction (e.g. materials), electrical characteristics (e.g. frequency response of the return loss, gain and radiation pattern), electrical/mechanical tuning mechanisms (if any), and mounting locations. The metallic portions of the vehicle body and the antenna location are the most important parameters that define an exposure scenario. The shape and features of the vehicle body (e.g. windows) shall be representative of the typical application of the communication device without complicating the computational modelling unnecessarily. The model of the pavement shall also be included in the simulation.
5.2 Vehicle modelling To obtain reliable and repeatable simulation results, a specific CAD model of the vehicle has been defined and is available with this document. To conduct a successful simulation according to this document, the CAD model of this standardized vehicle shall be used. Some results obtained using this standardized vehicle model may not be applicable for certain other vehicle types or different antenna installation conditions, e.g. if non-metallic roof installation is allowed. The standardized vehicle model defined in this document for compliance assessment is applicable to all vehicle models when the following conditions are met. For either roof mount or trunk mount antenna, the distance to the bystander shall be defined with the antenna mounted according to the installation requirements. To help ensure the most conservative configuration(s) are considered for exposure assessment, the bystander separation distance shall be no greater than the minimum separation distance required for compliance as stated in the installation instructions. The same conditions shall apply to the separation distance between the antenna and the passenger except for the roof mount antenna configurations where the passenger is partially shielded by the metal roof. With such considerations, the impact of the vehicle model does not need to be considered when performing simulations using the standardized vehicle model, which makes this evaluation process practical.IEC IEEE 62704-2 pdf download.