Radome-grade PMI Foam

Created on 11.13

As a key component of aerospace, marine, and ground radar equipment, the radome’s core function is to protect the internal radar system from harsh environmental erosion (such as high temperature, high-speed airflow, salt spray corrosion, etc.), while minimizing the blocking and interference of radar electromagnetic waves to ensure signal transmission efficiency and detection accuracy.

Polymethacrylimide (PMI) foam has become the preferred material for radome sandwich structures due to its excellent comprehensive performance. Its low dielectric loss characteristic (usually dielectric loss tangent ≤ 0.005@10GHz) can effectively reduce electromagnetic wave energy attenuation and ensure radar signal penetration; high specific strength (tensile strength ≥ 40MPa, density only 40-80kg/m³) and high rigidity can support the radome to maintain structural integrity under extreme working conditions, resisting aerodynamic loads and impacts; good processability enables complex curved surface forming, adapting to the design requirements of different types of radomes.

In the aerospace field, airborne radomes must withstand harsh environmental tests such as extreme high-altitude temperatures (-55℃~120℃), high-speed aerodynamic loads (Mach number above 2.0), and intense ultraviolet radiation. Through formula optimization and molding process upgrading, PMI foam exhibits excellent high and low temperature stability (heat distortion temperature ≥ 180℃), with no obvious shrinkage or deformation under extreme temperature difference environments, ensuring the structural dimensional accuracy of the radome; its extremely low dielectric loss and uniform dielectric constant (ε=1.05-1.15@10GHz) can effectively reduce electromagnetic wave reflection and scattering, guaranteeing the detection range and resolution of radar systems in complex air combat environments. It is widely used in radar protection devices of various aircraft such as civil aircraft, helicopters, and UAVs.

In the marine field, shipborne radomes need to cope with high humidity, salt spray corrosion, and wind-wave impact in the marine environment. After moisture-proof and anti-corrosion modification, PMI foam can effectively resist salt spray erosion. Its closed-cell structure (closed-cell rate ≥ 95%) can prevent moisture penetration, ensuring the radome maintains stable performance in long-term marine service environments. It is suitable for radar system protection of various ships such as destroyers and frigates.

Through special designs (such as gradient dielectric structure design, surface coating modification, etc.), the performance of PMI foam radomes can be further improved. For example, the adoption of gradient dielectric PMI foam core can optimize the electromagnetic wave refraction path and reduce signal reflection and scattering; coating the foam surface with a low dielectric loss coating can enhance resistance to environmental erosion, while further reducing dielectric loss, realizing the efficient synergy of the radome’s dual functions of "protection and wave transmission".