Optimizing Antenna Layout in Passenger Car Glass for Improved Reception

• Analytics & Modeling - Digital Twin / Simulation
• Robots - Autonomous Guided Vehicles (AGV)

• Automotive
• Glass

• Product Research & Development

• Transportation Simulation
• Vehicle Performance Monitoring

• Hardware Design & Engineering Services
• System Integration

Daimler, a German automotive technology leader, faced a challenge in optimizing the layout of FM, DAB, RKE & TV-antennas in multilayer windscreens. The integration of antennas in windscreens has become popular due to enhanced aesthetics and increased antenna surface area, which enables improved reception. However, the design of such antennas is complex, requiring the ability to analyze electromagnetic interactions between thinly layered dielectrics, thin embedded wires, and the surrounding vehicle body. The vehicle body forms part of the antenna in the frequency range of FM-, DAB- RKEand TV-antennas, leading to the need for the glass antennas to be adapted or redesigned for each car line and variant. Different glass types and configurations can change the impedances of the multiport antennas. Additionally, different antenna concepts are needed for different vehicle types.

The customer in this case study is Daimler, a German automotive technology leader. Daimler has a long-standing relationship with Altair for vehicle antennas and electromagnetic compatibility (EMC) simulation and was one of the first manufacturers to change its windscreen antenna development from a measurement-driven to a simulation-driven process. This change in approach has enabled the creation of mature antenna layouts with high levels of performance at an early development phase. Simulated EMC emission tests determine coupling to the windscreen antennas. Daimler wanted to make the optimization process of its multi-port antenna more efficient and turned to Altair for assistance.

To make the optimization process of its multi-port antenna more efficient, Daimler turned to Altair for assistance. Altair ProductDesign suggested that these issues could be addressed with a jointly developed windscreen antenna analysis method within HyperWorks’ electromagnetic suite, FEKO. The solution would have to represent the dielectric properties of multiple layers analytically, enabling a very efficient simulation of windscreen antennas. In addition, the complete system must be considered for the evaluation of the different antennas. To do this efficiently, Altair ProductDesign implemented multi-port post-processing, which allowed different port configurations to be re-evaluated without re-running the solver. The method would be extremely helpful when considering amplifier configurations for different variants. The antenna geometry of the initial layout was modelled within the vehicle model using FEKO. The multiple layer glass structure was represented and the antenna structures were placed at arbitrary layers. The ground path from the amplifier PCB across the amplifier housing to the vehicle body was included in the model.

• The antenna optimization procedure developed by Altair ProductDesign, using FEKO's Windscreen Analysis Tool, has become a standard process for all windscreen antenna layouts of new car lines and is realized in close cooperation with glass suppliers. The process ensures a highly mature antenna layout and also allows for the evaluation of the electromagnetic noise at the antenna port for different emission scenarios, which helps to identify worst case EMC scenarios. Since the number of vehicle variants is ever increasing for Daimler – and simultaneously the number of hardware prototypes is reduced – this variety can only be managed efficiently with the use of simulation technology.

• Improved antenna performance at early vehicle development phase.
• Mature antenna layout for EMC emission testing
• Up to 8 dB better performance with the optimized design