Simulation aids vehicle antenna placement

Software-based simulation is helping designers with in- vehicle antenna placement, says M Bandinelli of Siemens


odern vehicles are a significant challenge in terms of electromagnetic performance thanks to the high levels of connectivity inside and outside the vehicle as part of vehicle-to-vehicle (V2V) and vehicle-to-

infrastructure (V2x) communication requirements. While individual sub-assemblies and components

are subjected to rigorous EMC testing protocols, the “whole vehicle” performance can still be compromised. To reduce the risk of EMC and performance problems, antenna positioning and the avoidance of RFI coupling is important but difficult to achieve. On behalf of Siemens, M Bandinelli explains that

it is critical for designers and engineers to find the ideal locations for antennas while also considering all the constraints and complexities related to electromagnetic interference. These growing complexities put pressure on developers to maintain performance amid time-to-market and budget constraints. With this in mind, an approach that relies on trial-and-error is too expensive, too time- consuming and no longer acceptable.

ANTENNA DESIGN According to Bandinelli, automotive antennas operate in a complex environment and this must be accounted for this in their design. Their own requirements must also be considered, such as shaped pattern, size, weight, installation constraints and regulations. The antenna must work as part of an overall

system with infotainment, other passenger comfort applications, vehicle sensors for advanced driver assist systems (ADAS) and other applications, all of which must operate in all conditions. In this respect, the field radiated by an antenna

may cause electromagnetic interference with other antenna-based systems. The power radiated by a transmitting antenna may couple to a receiving antenna causing desensitisation which risks potential malfunctioning. Such electromagnetic interference risks must be controlled at design level.

18 /// Testing & Test Houses /// April 2020

❱❱ Complex signal interactions in vehicles can be simulated at early design stages to minimise compliance problems

SIMULATION With trial-and-error and chance being unacceptable design approaches, one alternative

is to use simulation software during design. This can help engineers to understand how electromagnetic performance can potentially affect and interfere with product performance. For example, electrical motors, sensors and antennas are more prevalent and play a bigger role in the development process and must be part of electromagnetic simulation, which essentially means “viewing the invisible,” such as E-H field, currents, charge, voltages and energy/power distribution all along the 3D space, says Bandinelli. Progress in simulation technology has produced a

comprehensive digital twin, which can provide valid support to effectively and efficiently address design issues. Measurements are then used to tune the digital twin and to verify the performance of the final antenna and platform configuration. The digital twin could also help simulate the exact

3D reality, allow designers and engineers to explore the design space and find trade-offs both at antenna and installation levels, including minimising interaction with surrounding structures and interference with co-installed antennas and systems. Just like similar technology applied in other

disciplines, electromagnetic simulation can be used for multiple purposes like analysis, diagnostics and certification support. It also enables faster prototyping and more efficient exploration of the design configuration in the early phases when no hardware is available. The software can be used to assess the effect of ageing and modifications to the electromagnetic environment as well as the impact of the physical environment. Without simulation, vehicles would have to be

tested on 11 billion miles of road — an unrealistic and impossible task. Simulation is helping reduce the process from months down to days. That’s why developers are increasingly using digital twin and simulation to test and validate antenna systems. T&TH

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