In this paper, we present a tri-band electromagnetic absorber with insensitive properties. A rotational symmetry structure with a metallic ground is proposed for the design of the metamaterial absorber. Calculation results show that the absorber has three perfect absorption points at 4.76 GHz, 7.61 GHz and 10.84 GHz with the corresponding absorption rates of 96.7%, 97.8%, and 99.3%. An experiment is given, and the results verify our design. Such a tri-band absorber has the merits of high absorption rate, stable performance with various incident angles and different polarizations.
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