A novel electromagnetic absorber design based on periodic Salisbury screens

This paper presents the actual production procedure of an electromagnetic absorber by using the well-known Salisbury screens, which are distributed periodically to overcome the bonding difficulty between the upper and lower layers of the absorbing materials. In particular, the unit cell of the Salisbury screen is square with a 15 cm in side-length (5λ at the resonance frequency, 10 GHz) and 30 μm in thickness. The return loss at the resonance frequency can reach 34 dB (equivalent to more than 99.9% of EM wave absorption) with a bandwidth of 10 dB by 6 GHz. The absorber is consisted of 4 × 4 unit cells with a gap of 5mm (0.2λ) between them. The central frequency is 12 GHz, with a return loss by 27 dB (i.e., more than 99% of EM wave absorption) and a bandwidth of 10dB by 6.6 GHz.