Advanced Driver Assistance Systems Augmented with Conductive Compounds

Sabic has expanded its specialty materials portfolio for advanced driver assistance systems (ADAS) to further strengthen occupant and pedestrian safety. The company’s two new LNPStat-Kon compounds are well suited for ADAS radar absorbers and can help propel adoption of millimeter wave (mmWave) radar, which significantly improves sensor accuracy and range. By providing robust, high-resolution information about remote objects, mmWave radar could enhance driving safety and support the trend toward the use of autonomous vehicles.

A significant challenge for ADAS radars is ghost imaging, which can cause sensors to act on “false positive” information due to erroneous radar frequencies entering the sensor lens. Addressing this issue will become increasingly important as the ADAS component count in cars is expected to increase dramatically over the next 10 years, with as many as seven to eight radar devices per car. Sabic LNP Stat-Kon compounds exhibit radar-absorbing properties that can help to reduce the number of ghost images when deployed within the ADAS unit or as an absorbing cone or sheet.

The new LNP Stat-Kon WDF40RID and WDF40RI compounds address a key challenge of mmWave radar — its increased noise-to-signal ratio. To minimize noise that interferes with the transmission of the main radar signal, these compounds provide a high dissipation factor (Df) for efficient absorption. Compared to other semi-crystalline glass filled materials, Sabic’s new glass-fiber-reinforced grades deliver higher absorption and lower reflectivity. In addition, they offer ultra-high flow and very low warpage, empowering customers to create new designs for internal and external single-layer absorbers, or to optimize traditional metal-backed absorbers.

Stat-Kon WDF40RID is based on a polybutylene terephthalate (PBT) resin matrix and contains 20% glass-fiber reinforcement plus proprietary electrically conductive and radar-absorbing fillers.

“Steady improvements in accuracy and reliability are helping ADAS technologies increase vehicle safety,” said Joshua Chiaw, director, Business Management, LNP & NORYL, Specialties, Sabic. “To help accelerate ADAS improvements, Sabic continues to add new specialty materials with exceptional properties that have the potential to enhance the design and performance of ADAS sensors' ecosystem, including radar, LiDAR, and camera components. Our new LNP Stat-Kon compounds, well suited for radar absorbers, could help propel the shift to higher-frequency mmWave radar to enable better image resolution and greater range. These new solutions reflect our extensive experience with both ADAS and the mobility sector as a whole.”

Less noise, better radar performance

LNP Stat-Kon WDF40RID exhibits high absorption — up to 75% at 77 GHz — and controlled reflection as low as 25% at 77 GHz, which together can significantly reduce noise. This innovative product can surpass incumbent materials in higher absorption and lower reflection by as much as 10% on a flat design and can be further optimized with appropriate design shapes. LNP Stat-Kon WDF40RID compound delivers consistent performance across mmWave frequencies used for ADAS radar (76-81 GHz band). By maximizing noise dissipation, the new compound can help minimize ghost images and sidelobe interference, resulting in greater ADAS radar resolution and accuracy.

LNP Stat-Kon WDF40RI is formulated for metal-backed radar absorbers and can raise radio wave absorption to nearly 80%, while lowering reflection below 20%, and provide total shielding when working with metal backs. Both grades’ noise-shielding performance is consistent across mmWave frequencies between 75 and 110 GHz.

Favorable flow properties power new designs

Incumbent radar absorber materials typically exhibit high viscosity and reduced flow stemming from the use of conductive additives. High viscosity limits ADAS manufacturers in designing thin-wall internal absorbers or large external absorbers that surround the radar sensor. The LNP Stat-Kon WDF40RID compound has an improved flow rate enabling walls as thin as 1 mm for interior radar absorbers, reducing side lobe noise and freeing up space for additional electronics. From a processing standpoint, high flow can sharply reduce scrap from short shots and increase yield. The new compound also delivers excellent dimensional stability at long flow lengths up to 20 cm. Its low warpage supports the design of large, curved, exterior absorbers to reduce noise from adjacent metal parts.

“Our development team applied their ingenuity and deep technical knowledge to balance conductivity and flow properties in our new LNP Stat-Kon compounds, while ensuring exceptional noise diffusion performance,” said Jenny Wang, director, Formulation & Application, APAC, Specialties, Sabic. “These new products have addressed key drawbacks of currently available materials, opening the door to new internal and external absorber designs and improved processability. Adoption of these new compounds can help the industry advance the state of the art in ADAS radar.”