Siepel develops advanced EMC and microwave absorbers designed to deliver high performance across a wide range of frequencies. Manufactured in France, these absorbers are the result of extensive research focused on optimizing both geometry and material composition. A key innovation in Siepel’s absorbers is a proprietary LIV coating, which combines flexibility and durability while allowing for customization in color and brightness, thereby offering a high-performance alternative to traditional white caps that can compromise efficiency at high operating frequencies.
EMC and microwave absorbers form a vital component in EMI/EMC testing. They help in minimizing electromagnetic wave reflections and ensure controlled and interference-free measurements. They are commonly used in shielded rooms to create anechoic chambers, enabling accurate, repeatable EMC and antenna measurements in conditions that simulate free space. The performance of these absorbers directly influences the accuracy and reliability of measurements. Factors such as absorber height (linked to wavelength), material composition, and layout within a chamber are carefully chosen to ensure effective attenuation across the target frequency range—from a few MHz to several tens of GHz.
Key EMC and Microwave Absorbers Developed by Siepel
Siepel offers a wide range of EMC and Microwave absorbers designed to meet the requirements of standardized EMC tests across various applications, including, antenna measurements (radiation pattern, VSWR, PIM), RF systems verification (satellites, WiFi, mobile phones, 5G …), and radar characterization or Radar Cross Section (RCS).
SEA-PM – Broadband Pyramidal Absorbers
SEA-PM absorbers are designed for lining anechoic chambers used in EMC testing across automotive, aerospace, and defense sectors. They offer excellent physical properties and are available with Siepel’s LIV coating for added flexibility and customization. These absorbers meet cleanroom standards (ISO Class 4), comply with REACH & RoHS regulations, and adhere to key fire safety standards. Delivered factory-cut and ready to install, they are supported with full chamber design and performance calculations.
SEA-TM – Broadband Truncated Absorbers
SEA-TM absorbers provide robust performance in EMC applications and share many of the same benefits as SEA-PM, including cleanroom compatibility (ISO Class 4), REACH & RoHS compliance, and certified fire resistance. The truncated design helps optimize space while maintaining absorber performance. Factory-prepared for easy installation, SEA-TM products also include support for chamber design and performance assessment.
SEA-HY – Hybrid Pyramidal Absorbers
SEA-HY absorbers combine pyramidal RF absorber foam with ferrite tiles, making them ideal for EMC testing in industrial, automotive, aerospace, and defense sectors (compliant with CISPR, MIL-STD, and DO standards). They are available as complete hybrid panels or as separate components, offering flexibility in chamber design.
SEA-HYT – Hybrid Truncated Absorbers
SEA-HYT absorbers are the space-saving version of the SEA-HY series, designed to maximize usable volume inside EMC chambers without compromising performance. Suitable for industrial and defense standards, they offer high reflectivity performance across a wide frequency band. Like other Siepel absorbers, SEA-HYT models meet ISO Class 4 cleanroom standards, are REACH & RoHS compliant, fire-tested, and delivered factory-cut for quick installation.
SEA-FE absorbers are made of ferrite tiles, ideal for EMC chambers designed for EMI and EMS testing up to 1 GHz. To achieve broadband performance up to 18 GHz or higher, hybrid foam absorbers can be added on top. This combination ensures consistent performance across a wide frequency range, making them suitable for both commercial and defense EMC standards.
SEA-F – Flat Absorbers
SEA-F flat absorbers are designed to cover corners in fully or semi-anechoic chambers, enhancing overall performance. They operate from 200 MHz to 40 GHz, handle power up to 1.6 kW/m², and withstand temperatures of up to +160°C. These absorbers feature Siepel’s LIV coating for flexibility and customization, comply with ISO Class 4 cleanroom standards, meet REACH & RoHS directives, and adhere to international fire safety standards. Delivered factory-cut, they are easy to install and integrate seamlessly into chamber designs.
SEA-MLM – Multi-layer absorbers
SEA-MLM is a premium series of broadband high-end multilayer absorbers. Two references are proposed: SEA-3LM (3 layers) and SEA-5LM (5 layers). They are used to cover all metallic surfaces, masts and antenna bases. They also contribute to the reduction of coupling effects between antennas. Despite their low apparent thickness, SEA-MLM offer high levels of absorption.
SEA-MP absorbers are designed for areas with intermediate electromagnetic field levels, offering power handling up to 3.2 kW/m². Ideal for compact base stations and antenna measurement chambers used in telecom, satellite, and defense applications, this newly developed model provides a balance between performance and affordability. It features the LIV-blue coating for flexibility and color customization, and meets REACH, RoHS, and key international fire safety standards.
SEA-HP absorbers are honeycomb-type, high-performance solutions capable of withstanding power levels up to 15 kW/m². They are essential for high-power zones in compact bases and antenna measurement chambers. Built for durability and long-term use, SEA-HP comes with a 25-year RF performance warranty and is fully compliant with REACH, RoHS, and fire safety standards.
SEA-WM – Wedge shape absorbers
These wedge-shape absorbers are integrated into compact bases and anechoic chambers. SEA-WM are designed to ensure high performance in chambers with incidence angles above 50°. The dihedral shape of the SEA-WM, guiding the reflected wave, can be integrated into anechoic chambers for the measurement of antenna patterns or Radar Cross Section (RCS).
They are flat and rigid absorbers, their technology (PU foams wrapped into vinyl cover) allows access to the equipment in a full anechoic chamber. SEA-WW specifications are taken into account when calculating the overall performance of the chamber and these absorbers are easy to transport while enabling a clean environment for EMC testing.
SEA-WP – Weatherproof Absorbers
SEA-WP absorbers are outdoor-ready, pyramidal absorbers sealed with a protective coating to ensure weather resistance and long-term durability. Ideal for external installations, they are used to cover metallic surfaces or reduce Radar Cross Section (RCS) in harsh environmental conditions. These absorbers offer excellent physical properties, are customizable in shape and size, and comply with REACH and RoHS standards.
SEA-CM absorbers feature a convoluted shape and are typically used to cover antenna positioners or masts within anechoic chambers. Their low profile makes them suitable for high-frequency applications. SEA-CM absorbers come with Siepel’s LIV coating for aesthetic flexibility, meet ISO Class 4 cleanroom standards, and are compliant with REACH, RoHS, and major fire safety regulations.
Siepel’s absorbers can also be customized to cater to the test suite.
Siepel is a French company that specializes in designing, manufacturing, and installing Faraday cages, anechoic chambers, reverberation chambers, and electromagnetic absorbers used for antenna testing and EMC (Electromagnetic Compatibility). Founded in 1986 and based in La Trinité sur Mer, Siepel became part of Vinci Energies Group in 2021. Their high-tech products are built on proven industrial solutions and can be customized for turnkey projects or offered as ready-made items. Siepel serves advanced industries like defense, space, telecom, and automotive, working with both public and private clients.