A SiC/C foam microwave absorbing material for PIM darkroom box in simulating space environment

Passive intermodulation (PIM) phenomenon is a severe issue facing by communication satellites, so the satellites need to be tested in PIM darkroom box equipped with microwave absorbing materials. In the present paper, a SiC/C foam microwave absorbing material (SiC/C FMAM) for space environments was developed, and its electromagnetic parameters could be readily regulated by carbon pyrolytic graphitization. Furthermore, for better structure design, simulation calculations were carried out as well. A sharp-cone microwave absorbing structure of SiC/C FMAM with height of 84 mm was designed, and its reflectivity was lower than −25dB in the frequency range of 1.8GHz–2.5 GHz. In addition, the total mass loss, collected volatile condensable material, hemispherical infrared emissivity and thermal conductivity were 1.1%, 0.01%, 0.896 and 0.453W/K·m, respectively. So the as-prepared SiC/C FMAM could meet various requirements under the thermal vacuum space environments. It was revealed that the PIM signal power of the darkroom box equipped with the SiC/C FMAM sharp-cone microwave absorbing structure was below −150dBm. The SiC/C FMAM exhibited attractive application in thermal vacuum space environments.