Investigations On Novel Electromagnetic Metamaterials Absorber

Electromagnetic metamaterial（EMM）which is one kind of artificial microstructure has a lot of strange properties and has become a rapidly developing research in recent years.Therefore,researchers have proposed a kind of composite absorbing material consisting of EMM structure and dielectric substrate,viz.metamaterial absorber（MMA）.Based on EMM theory,absorber design and application background,one kind of flexible broadband metamaterial absorber,absorber with a transmission band and non-reciprocal absorber have been designed.In Part I of this paper,a novel broadband flexible metamaterial absorber,which is based on high impedance surface（HIS）has been investigated.The polarization-insensitive absorber can suppress the backward RCS by about 10dBm2.Numerically simulated results indicate that the HIS metamaterial absorber（HIS-MA）obtains 11.14 GHz wide absorption from 6.86 GHz to 18 GHz with the absorption over 90%.The main innovation points of the proposed flexible metamaterial absorber are using HIS instead of lumped elements which is more environmental friendly and using flexible substrate instead of rigid substrate and thinner（0.125λ₀）than the same kind of absorber with HIS（0.2λ₀）.In Part II of this paper,the proposed absorber can obtain the bandwidth with the absorption over 90% in the frequency range of 7-16 GHz with a transparent window at 2.9 GHz.Losses in the high-impedance surface are introduced by printing the periodic pattern through resistive inks and hence avoiding the typical soldering of lumped resistors.One kind of MMA with stereoscopic structure is proposed in Part III of this paper,which can achieve non-reciprocity of both absorption and transmission in two modes.The innovation point of this work is using two pieces of metamaterial structure which are orthogonal and asymmetric to realize the non-reciprocity properties when the microwave incident the absorber in TE polarization at wide-angel.