▎ 摘　　要

In this work, the authors propose a graphene-based tunable perfect metamaterial absorber at microwaves that can achieve perfect absorption at all angles. This is realized by stacking an unpatterned graphene sandwich structure and a dielectric layer on top of a mushroom-type high impedance surface whose resonant frequency is stable for all angles of incidence. A perfect-absorption-angle tunable absorber working at TM polarization is designed and realized, achieving perfect absorption covering a wide range of angles from normal to grazing incidence at the same frequency when the impedance of graphene is modulated by different bias voltages. The design concept of integrating different tunable materials and meta-structures opens up promising possibilities for wave manipulation with applications in smart and multifunctional electromagnetic devices.