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Utilization of Foamed Resin SunForce™ in Millimeter-Wave Radar Radomes with Snow Melting Heaters 

Challenges of Millimeter-wave Radar Radomes with Snow Melting Heaters

Among the obstacle detection systems installed in automobiles, millimeter-wave radar stands out for its high detection capabilities even in harsh conditions such as rainfall, dense fog, and nighttime. It has become an indispensable element in autonomous driving technology.

However, during snowfall, the accumulation of snow on the radome can increase the reflection of millimeter waves, leading to decreased detection performance. To address this issue, technology that places heaters in the radome to melt the snow has been put into practical use.

Advantages of the Insulated Structure Using SunForce™

In existing millimeter-wave radar radomes with heaters, the heat from the heater spreads evenly inside the radome, so only about half of the generated heat contributes to melting the snow.

To solve this problem, Asahi Kasei proposes a structure that positions "SunForce™," a material made by foaming modified PPE resin, on the back of the millimeter-wave radar radome. Because of SunForce™'s high insulation properties and low dielectric characteristics, it enables the effective use of heat generated by the heater while minimizing the attenuation of electromagnetic waves in the millimeter-wave band.​

Features of Foamed Resin SunForce™

• Significant Reduction in Power Consumption: SunForce™ is a resin foam with a fine, closed-cell structure, offering high insulation properties. As shown in the diagram below, when using SunForce™ with a thickness of 3mm and a foaming ratio of 10x, it is possible to reduce the heater power consumption required to heat the millimeter-wave radar radome.

• Reduction of Temperature Unevenness and Maximum Temperature of the Radome: The high insulation properties of SunForce™ allow for a reduction in the heater output required to achieve a radome surface temperature of 15°C. This helps to reduce temperature unevenness on the radome surface and lowers the maximum temperature of the radome areas in contact with the heater.

• High Millimeter-Wave Transmittance: SunForce™ is made from a modified PPE resin with very low dielectric properties due to further foaming. This minimizes the attenuation of high-frequency electromagnetic waves.

• Additional Features of SunForce™: In addition to its high insulation and low dielectric properties, SunForce™ has the following features, enabling the design that maximizes the performance of automotive radars:

Features and effects of SunForce™
Dielectric properties	Low dielectric constant (high radio wave permeability) due to resin origin + foaming
Thermal insulation	Improved heater utilization efficiency, heat shielding between hot and non-hot areas (thermal management effect)
Flame resistance	UL94 V-0 certified
Filling in space	Prevention of condensation, insulation, and thermal insulation by replacing air with foam
Formability	Fixed parts (reduction in number of parts and assembly load)
Others	Heat resistance, Waterproof

As the demand for power-saving technologies in electric vehicles (EVs) continues to grow, millimeter-wave radar radomes with snow melting heaters using SunForce™ foamed resin significantly contribute to improved EV convenience by achieving efficient snow melting and high millimeter-wave transmittance simultaneously.  This raises expectations for extended driving range and longer battery life..

→　自動車技術会論文集54巻(2023)3号掲載「融雪機能付きヒーターレドームへ発泡樹脂を配することによる消費電力低減効果の解析的予測とミリ波透過性への影響の確認」はこちら

or more detailed information or to request samples regarding the utilization of foamed resin SunForce™ for millimeter-wave radar radomes with snow melting heaters, please contact us.