Boards are often stacked to save on space –multilayering. You need to consider the dimensional and electrical features while designing multilayer Automotive PCBs. Below are the materials that are ideal for building multilayer boards:

RO4000: It features the low-thermal coefficient of the dielectric constant to reduce phase variations and the CTE z-axis, closely related to copper. RO4000 materials are therefore suitable materials for making multilayer boards.

Flex-rigid materials: The RO3000 materials are particularly ideal for low-loss microwave boards, though they do not perform well in multilayer boards because of their dimensional and dielectric changes with temperature. However, they can perform well in multilayer PCBs if you work on their structural properties by integrating their electrical properties with the mechanical elements of polyimide materials.