Effect of 3D woven fabrics on the microwave absorbing and mechanical properties of gypsum composites using carbon black as an absorbent

Abstract

In order to improve the S and X band microwave absorbing properties of gypsum based composites with carbon black (CB) as an absorbent, three-dimensional (3D) woven fabric was embedded into the composites and the effects of 3D woven fabric on the dielectric properties, wave absorption, and mechanical properties were investigated. The results show that the microwave absorbing properties of the composites are visibly enhanced after being embedded with the 3D woven fabric. The minimum reflection loss reaches −16 dB and the bandwidth for −10 dB is 1.4 GHz in the S band; and in the X band the minimum reflection loss of −25 dB can be obtained and the bandwidth for −10 dB reaches 2.5 GHz. The introduction of the 3D woven fabrics can decrease the complex permittivity of the composites, resulting in the improvement of impedance matching. Moreover, a new microwave attenuation path is provided by the ‘hollow fibers’ of 3D woven fabric, which can enhance the microwave attenuation capacity. Thus, using 3D woven fabric is an effective way to improve the microwave absorption of an absorber with a dielectric loss absorbent. In addition, the flexural strength of the composites can be evidently enhanced by 3D woven fabrics.