Microwave absorbing properties of activated carbon-fiber felt screens (vertical-arranged carbon fibers)/epoxy resin composites

Microwave absorbing properties of the composites containing inductive activated carbon-fiber felt screens (IACFFSs) and vertical-arranged carbon fibers (VACFs) have been investigated, respectively. It is found that the reflection properties of the composites containing IACFFSs are greatly affected by the element configurations of IACFFSs. With the interval between strips and the width of the strips in the IACFFS decreased, the absorbing properties of the composites are improved. The composite obtains a reflection loss below −10 dB in 8–18 GHz, which covers the frequency region of the radar, when the interval between strips and the width of the strips are 7 mm and 5 mm, respectively. The space between the adjacent carbon fibers is critical for the absorbing characteristics of the composites containing VACFs. The composite achieves a reflection loss below −10 dB over 7.6 GHz when the space is 4 mm. By applying the block design method, the composite was divided into four sub-regions, which were centrosymmetrical and included two IACFFSs and two VACF regions. The composite achieves a reflection loss below −20 dB in 11.8–18 GHz and the minimum value reaches −30 dB when the interval between strips, the width of the strips and the fiber space are 10 mm, 5 mm and 8 mm, respectively.