Microwave absorption enhancement of rectangular activated carbon fibers screen composites

The radar absorbing materials composited of activated carbon fibers (ACF) as wave-absorber and glass fibers (GF) as impedance modifier were successfully prepared. The structure parameters of rectangular ACF felt screen, the influences of GF-piece and the reflection properties were investigated. It was observed that the effective bandwidth (the reflection loss below - 10 dB) increased with the aspect ratio (a/b) increasing, but decreased with aperture spacing (delta) increasing. A double absorption peak (16.1 dB and 14.2 dB) for the optimized configuration (a/b = 3, iota = 5 mm, a = 30 mm) appeared at 5.8 GHz and 16.9 GHz, and a wide absorption bandwidth (4-17.6 GHz) could be achieved. When a 30 mm x 15 mm rectangular aperture was filled by GF-piece of 20 mm x 10 mm, the effective bandwidth was improved to 12.1 GHz. The composites with a wide absorption bandwidth could be achieved via designing the proper element parameters and adjusting the composition of ACF and GF. (C) 2015 Elsevier Ltd. All rights reserved.