In this study, highly filled high-temperature thermoplastics (polyethersulfone [PES], polyphenylensulfide, polyetherimide [PEI], and polyetheretherketone [PEEK]) are used as insulating substrate for printed circuit boards (PCBs). Talc has been added to the thermoplastics to adjust their coefficient of thermal expansion (CTE) to the CTE of the copper circuits, thus reducing the possibility of failure of the PCB owing to thermal stress. The dielectric properties of the substrates were analyzed between 10 MHz and 1 GHz, depending on filler fraction and water absorption. An increase of filler fraction resulted in an increase of dielectric constant e 0 . As expected, the absorption of water molecules led to an increase of both tan d and e 0 . Moreover, the combination of filler and absorbed water resulted in a strong increase of the dielectric loss factor at low frequencies. Finally, theoretical approaches with fitting parameters could be employed to precisely describe the measured properties between 0.8 and 1 GHz. This study shows that most of the materials investigated here, namely highly filled PPS, PEI, and PEEK, are suitable for high-frequency PCB applications.

PurposeThe purpose of this paper is to investigate and present the properties of a new substrate material based on thermoplastic polymers (so‐called LuVo Board) for high‐frequency applications.Design/methodology/approachThe thermal, mechanical and electrical properties of a new thermoplastic substrate are investigated and compared to conventional substrates for printed circuit board (PCB) applications.FindingsThe new LuVo Board exhibits similar properties to commercially available high‐performance substrates. The main advantage of the LuVo Board is a reduction of manufacturing costs in comparison to conventional substrates, as a highly automated manufacturing process can be employed. Moreover, the LuVo Board exhibits some further advantages: the material is inherently flame resistant and can be thermally shaped after the assembly process.Originality/valueThis paper presents an entirely new thermoplastic substrate, which can be employed in high‐frequency applications. In comparison to standard materials, a further advantage of the thermoplastic substrate is lower production costs.