Challenges with 76-81GHz frequency band systems

New high-frequency radar operating in the 77 to 81GHz range will be better equipped to deliver improved safety and convenience drivers want from ADAS, due to improved spatial and velocity resolution. However, the technology requires silicon geranium (SiGe) chips, which generate excess heat and are expensive. When overheated, radar systems automatically shut down to prevent components from being damaged – temporarily preventing drivers from using it. High-frequency radar components also need to be two to three times smaller than previous generations to fit behind vehicle bumpers. As miniaturized designs are more susceptible to overheating, this increases risk of systems shutting down repeatedly.

Commonly used radar material solutions fail to overcome these challenges. Low power module solutions generate less heat, but offer poor radar resolution. Die-cast aluminum options control heat levels effectively, but require expensive secondary processing and are difficult to miniaturize. Manufacturers require material solutions that support compact radar designs built to manage high thermal loads. Final products must also be cost-comparable to previous 24GHz systems to be accessible to non-luxury automotive OEMs.

Optimizing radar performance while reducing costs also requires replacing materials traditionally used for key system components. Radomes must offer a low dielectric constant (Dk) and dissipation factor (Df) to ensure high radar resolution and low signal losses. Existing high performance materials, such as polyetherimide (PEI) solutions are very expensive while traditional polybutylene terephthalate (PBT) options may have a high Dk. Radar midframes need to allow signals to be fully absorbed and minimize reflections that lower resolution. Today, midframes are often made with metal components, but the high electrical conductivity of the material leads to high reflections. Metal-based back covers provide the high electromagnetic interference (EMI) shielding radar systems require and help remove heat from the unit. Yet this solution is expensive to manufacture with and is difficult to miniaturize due to the extra space required for sealings.

To successfully expand into the non-luxury vehicle market, radar suppliers need to deliver on automotive OEMs’ design and performance expectations. Envalior’s complete portfolio of laser-weldable thermoplastics for ADAS enables you to meet this challenge. Our materials provide best-in-class processing capabilities, dimensional stability and continuous use temperatures (CUT) required to cost-effectively develop final products that set you apart from the competition. Each material solution is tailored to the needs of each key system component.

Reliable, cost-effective radomes  

Manufacturers increasingly look to use polyphenylene sulfide (PPS) for radomes, as it is more affordable than PEI, and offers better performance in high-frequency radar systems compared to standard PBT. Our recently developed low Dk and Df Xytron® PPS delivers the high radar resolution and system reliability of PEI at the cost of standard PPS. With a CUT up to 210°C and excellent hydrolytic and chemical resistance, it ensures superior thermal load management, longer part lifetimes and low warpage. We’ve also enhanced our existing Arnite® offering to give customers continued access to a high-strength PBT option for radomes.

Maximizing midframe performance

More suppliers are replacing metal midframes with medium conductivity thermoplastics – in the range of 10E2-10E5 Wcm – that maximize signal absorption and minimize reflections. Yet, product designers want to further improve system reliability by optimizing radar signal absorption at 77 – 81GHz. This requires tuning midframe thickness to the material’s Dk and Df. Our Akulon® solution offers inherent high strength in thin-walled parts – enabling components to be designed thinner without mechanical limitations. The material’s Dk and Df can also be adjusted precisely, which allows manufacturers to easily modify designs in space constraint models without compromising system performance.

EMI-blocking back covers

Back covers need to effectively block EMI and manage high thermal loads to prevent system malfunction. Our portfolio’s Xytron and Arnite solutions deliver the high electrical and thermal conductivity required for excellent EMI shielding and heat transfer performance. This enables manufacturers to retire metal-based solutions with limited design flexibility, poor heat management and risk of part failure if metal coatings are delaminated or scratched during assembly. Envalior is also developing a laser welding process for bonding radomes and back covers, allowing customers to streamline production and reduce assembly costs.

Envalior is trusted by ADAS suppliers worldwide. Our research and development team works with you to select the right material grades from our portfolio and quickly build component prototypes. Extensive simulation support in optimizing each component’s radio-frequency performance simplifies design processes and eliminates the need for multiple testing cycles. As your complete material solutions provider, we’re ready to help you deliver automotive technology that transforms the industry.

The importance of EMI Shielding —the future of metal replacement in EVs