ROHACELL® Foam – Adaptable with Plenty of Room for Radar Beams

Antenna covers (radomes)

Nobody relies on visual cues any more in commercial and military aircraft operation. Radar devices have taken over multiple navigation and positioning tasks and have become an indispensable element of aircraft operation.

The covers of such radar devices, also known as radomes, are typically designed as sandwich composites. They have to match the shape of the aircraft, which can be a conventional plane, helicopter, or unmanned air vehicle (UAV). Because of the high speeds and exposure to foreign bodies, such covers must meet the highest mechanical requirements and may not interfere with radar beams in any way.

ROHACELL^® is the core material of choice for these applications, for example in grades IG/IG-F or WF, which have excellent mechanical strength and are very well suited for thermoforming into spherical or double-curved dishes. Since the dielectric properties of ROHACELL^® are very close to those of air, the PMI-based foam permits the passage of radar beams without any obstacles.

Antennas

Because the properties of ROHACELL^® are very similar to air, the material is also ideally suited for substrates or spacers in antennas. ROHACELL^® HF is designed for direct contact with metallic antenna panels. The ultrafine cell structure and guaranteed thickness within an accuracy range of +/-0.2 mm make the structural foam an ideal spacer for mobile and stationary antenna technology.
The range of applications for ROHACELL^® extends from miniature antennas in telephones to large-scale, landship-based antennas (see picture below) measuring 8 m x 2 m (26 feet by 7 feet). In combination with a copper or Kapton cover skin, ROHACELL^® is equally suitable for use as a mounting platform for functional antenna components and as spacers. The material can be formed into complex and even double-curved shapes. The foam shows very good impact resistance, whereas other foams do not pass the most common rain erosion test - they simply turn to dust.