Chamber Design for Automotive EMC and ADAS Testing

EMC testing is typically performed in shielded absorber lined enclosures, and the design of these chambers have evolved over the years to take advantage of improvements in material technology, and changes in the way tests are performed. Other RF measurements like antenna pattern or over the air (OTA) communication performance measurements are also performed in shielded absorber lined enclosures for many of the same reasons. One of the main reasons is to provide RF isolation from the outside environment to prevent external RF signals from interfering with the device under test (DUT) or vice versa. Another is the approximation of a free space environment with well controlled reflections. The degree to which this is required differs for the different measurement types. The automotive industry has seen the rapid development of modules and systems that perform functions very different from the older electromechanical units responsible for switching or simple logic control. In addition to many of the traditional functions, newer modules are now also responsible for electric drive functions, entertainment and communication using new modulation schemes, operating at higher frequencies, with bandwidth communication protocols, and antennas with more complex propagation patterns. Other modules are responsible for interpretation of the environment, with feedback to warning systems and control functions in an increasing number of use cases. Vehicles equipped with advanced driving assistance systems (ADAS) and autonomous driving systems (ADS) are growing with an increasing reliance on sensors and controls that perform safety critical functions. The aim of the paper is to discuss some of the different test chamber design options available with insight to the advantages and disadvantages as it relates to the key features of the systems being tested.