Radiation-absorbing composite materials

Radiation-absorbing materials (RAM) are becoming increasingly important in numerous industries. Whether in military technology, measurement technology, or automotive engineering - wherever sensitive electronics and high-precision sensors are used, effective protection against electromagnetic interference (EMI) is essential. Modern composite materials offer tailor-made solutions that can both shield electromagnetic waves and minimize radar and sensor signatures.

 

What are radar-absorbing materials (RAM)?

Radiation-absorbing materials are specially developed materials that absorb electromagnetic waves in the frequency range from 3 MHz to 300 GHz instead of reflecting them. They convert the incident RF radiation (radio frequency radiation) into heat energy, thereby reducing interference and the radar visibility of objects.

The effect is produced by two mechanisms:

1. Absorption of electromagnetic waves via dielectric, electrical, and/or magnetic losses.

2. Multiple internal reflections within the material structure, which greatly attenuate the radiation.

Since radar systems operate in a very wide frequency range, RAMs can be adapted to different areas of application.

 

Applications of radiation-absorbing materials

RAMs have a wide range of applications, from EMC protection measures to military stealth technology:

• Military camouflage: Reducing the radar cross section of aircraft, ships, and vehicles to minimize visibility to enemy radar systems
• Electromagnetic compatibility (EMC): Protection of sensitive electronics from interference by unwanted electromagnetic signals
• Anechoic chambers: Enabling precise measurements and testing of electronic components in interference-free environments
• Antenna and radar systems: Research and development to optimize system performance and signal quality
• Vehicle technology: Protection of sensitive radar sensors in assistance systems from interference caused by environmental influences
• Multispectral camouflage: Combination of radar, infrared, and thermal protection to minimize the visibility of vehicles or people

 

Advantages of composite materials: Tailor-made absorption

A key advantage of modern RAMs is their flexible manufacturability from plastics with conductive or ferromagnetic fillers. This opens up a wide range of design options:

• Flexible processing: extrusion, injection molding, deep drawing, 3D printing
• Operating temperatures above 300 °C: thanks to high-performance plastics such as PEEK or PEKK
• Additional functions: e.g., flame retardancy, temperature or weather resistance
• Customized shaping: from housings, seals, and pipes to large-area mats

 

Fraunhofer IFAM offers comprehensive expertise in the development and characterization of radiation-absorbing materials:

• Equipping housings, seals, and components with radar-absorbing properties
• Processing of a wide range of thermoplastics and thermoplastic elastomers
• Adaptation of material composition for specific frequency ranges
• Performance measurements up to 500 GHz and operating temperatures up to 250 °C
• Specialized solutions for automotive, aviation & space, and railway construction

 

Conclusion: Future technology for safety and precision

Radiation-absorbing composite materials are a key component of modern technologies. They ensure greater operational reliability of electronic systems, enable military camouflage technologies, and make an important contribution to interference-free measurement environments. Thanks to innovative manufacturing techniques and tailor-made material combinations, RAMs open up a wide range of applications in industry and research.