Design And Analysis Of Metamaterial Absorbers

Metamaterial absorbers are playing increasing important roles in fields of body safety protection, anechoic chamber, electromagnetic interference of communication system and electromagnetic compatibility and so on. The metamaterial absorber has obtained rapid development since it was put forward several years ago. It has developed from the original single band, fixed polarization and vertical incidence to multi-band, broadband or ultra-wideband, polarization-insensitivity and wide incident angle stability now. In this thesis, two multi-band metamaterial absorbers, two ultra-wideband metamaterial absorbers and two frequency-reconfigurable wideband metamaterial absorber are designed on basis of predecessors’ work. These proposed metamaterial absorbers have outstanding multi-band or wideband absorbing ability, charecteristics of good polarization-insensitiveness and wide incident angles, which provide a good candidate for designing full-featured metamaterial absorber. The main works of this thesis are as followings:1.a brief introduction to the electromagnetic metamaterial is made in this thesis, including the origin, concept, category and some current applications. Then, an analysis of concept, design and principle of metamaterial, which is a branch of metamaterials, is carried out. Besides, a brief introduction to the typical structures and breakthrough designs is made.2.based on the electromagnetic resonant principle, a dual-band metamaterial absorber and a triple-band metamaterial absorber are designed by introducing stubs. These two absorbers have outstanding multi-band absorbing ability. Besides, the designed two absorbers also have good performances on polarization-insensitiveness and wide incident angles, which provide an effective solution to designing multi-band absorber. The waveguide measurement method is utilized to verify these two metamaterial absorbers and the measured absorption results show good agreement with the simulated results.3.after designing the multi-band absorber, this thesis studies the planar ultra wideband metamaterial absorber, which is the current research focus and puts forward the method of loading resistors between the rings to design ultra wideband absorbers. Based on the proposed method, a double-ring ultra wideband absorber and a triple-ring ultra wideband absorber are designed. These two ultra wideband absorbers have outstanding wide absorbing band and good characteristics of polarization-insensitiveness and wide incident angles.4.two metamaterial absorbers, named ring-type frequency-reconfigurable absorber and stub-type frequency-reconfigurable absorber, are presented by combining the current research on tunable absorber and planar wideband absorber. The wide absorbing band can be tuned by selecting certain values of the lumped resistors and inductors. The waveguide measurement method is used to verify the absorbing performance of the ring-type frequency-reconfigurable absorber. The measured and simulated results are almost the same.