Combination of a full-wave method and ray tracing for radiation pattern simulations of antennas on vehicle roofs

An electromagnetic simulation approach combining a full-wave method with ray tracing is presented. This is used to simulate the radiation characteristic of a roof antenna system on a vehicle roof. The radiated fields of the antenna are first simulated for example with CST Microwave Studio (MWS) or measured and then utilized in the ray tracer. Besides to the modeling of the roof itself, also the antenna patterns are investigated. Small distances between the antenna and the vehicle roof do not allow to work with far-field assumptions. In this case, antennas with reduced extents are used, called subtransmitters [1]. These subtransmitters are represented by surface currents obtained from simulations with CST MWS. With this concept, also an antenna on the roof can be simulated with a ray tracing approach. Finally, more accurate results can be gained in Virtual Test Drive simulations. Furthermore, the simulation of radiation characteristics of vehicle roof antennas can be accelerated.