High-power pyramidal silicon carbide microwave absorbing material

Inherent Advantages of Silicon Carbide: As a wide-bandgap semiconductor, silicon carbide (SiC) exhibits exceptional high-temperature resistance (withstanding temperatures exceeding 1600°C), high thermal conductivity (approximately 150–490 W/(m·K)), and stable electromagnetic properties. Under high-power electromagnetic radiation, it is highly resistant to dielectric breakdown or performance degradation. Furthermore, it efficiently converts electromagnetic energy into thermal energy—via dielectric losses such as electronic polarization and lattice vibrations—and rapidly dissipates this heat, thereby preventing material failure caused by overheating.

Enhancement Effects of the Pyramidal Structure: The gradient morphology extending from the apex to the base creates an impedance gradient, facilitating a smooth impedance transition for electromagnetic waves traveling from air into the material, which significantly reduces surface reflection. Simultaneously, the multiple internal reflection pathways within the pyramidal structure extend the interaction time between the electromagnetic waves and the silicon carbide, thereby enhancing energy dissipation efficiency. This effect is particularly pronounced in high-frequency bands above 1 GHz, where absorption performance is exceptional (typically yielding a reflection loss of ≤ -30 dB).

High-Power Compatibility: The material possesses high overall mechanical strength (with a flexural strength of ≥ 300 MPa), enabling it to withstand electromagnetic power densities ranging from the kilowatt to the megawatt level (e.g., exceeding 1000 W/cm²). Moreover, it demonstrates excellent chemical stability in high-temperature (≤ 1000°C) and intense radiation environments, exhibiting no volatile emissions or structural disintegration. Consequently, it stands as one of the few absorbing materials currently capable of operating stably over extended periods within extreme electromagnetic environments.

The pyramidal elements of this material typically range in height from 50 to 300 mm. By adjusting parameters such as the cone angle, silicon carbide purity (ranging from 60% to 99%), and doping (e.g., through the introduction of elements such as carbon or boron), the material's electromagnetic absorption frequency band can be precisely tuned. This capability allows for a simultaneous balance between broad frequency coverage (spanning 2 GHz to 100 GHz) and high-power tolerance, establishing it as a critical protective material for applications involving intense electromagnetic fields.

Characteristics and Parameters of High-Power Pyramidal Silicon Carbide Microwave Absorbing Materials

Physical Properties

● Possesses excellent high-temperature stability

● Resistant to chemical corrosion

● Exhibits superior oxidation resistance

● Features a low coefficient of thermal expansion and excellent suitability for vacuum environments

Microwave Absorption Performance

● Operating frequency range: 0.5 GHz – 40 GHz. 

● Reflection loss: -20 dB to -50 dB (depending on frequency and design)

Flame Retardancy

● Inherently non-combustible

● Complies with the GB8624 Class A standard

Environmental Performance

● The base material is an inorganic ceramic

● Compared to traditional polyurethane-based absorbing materials, it offers distinct advantages such as inherent eco-friendliness, safety, non-toxicity, and recyclability

● Long service life, reducing the frequency of replacement