▎ 摘　　要

In this article, a low profile dynamically tunable microwave absorber is proposed, which consists of high impedance surface and graphene sandwiched structure. We theoretically demonstrate and experimentally verify that the proposed absorber can provide a dynamically tunable reflection range from larger than -3 dB to less than -30 dB at operating center frequency of 11.2 GHz. The entire thickness of this absorber is only 2.8 mm, nearly one tenth of working wavelength. In addition, a modified equivalent circuit model is proposed to explicate its absorption mechanism. At last, we fabricate a prototype absorber, measure its reflection coefficient in anechoic chamber. The experimental results agree well with the full wave simulation results. This work may provide a reference for design and fabrication of dynamically tunable microwave absorber based on large-scale graphene and may promote the actual applications of graphene at microwave frequency.