A tunable and polariztion-insensitive absorber based on the gravity field: from an ultra-wideband absorption to a single frequency absorption. (17th August 2021) - Gui, Di
Abstract: In this paper, a late-model and multifunctional device that can be tailored by the gravity field has been proposed and investigated. The water entailed in this device is covered with a dielectric substrate to make sure the integration of the whole device. The working mechanism of the introduced absorber is that the alteration of the positions of liquid water through gravity changes the distribution of the electromagnetic field and surface current on the absorber. Therefore, two states are involved in the absorber. In one state, more than 90% microwave absorption from 5.65 GHz to 12.40 GHz can be achieved. In another state rotated 180° in the xz plane, the microwave absorption changes from an ultra-wideband absorption into a single frequency absorption which reaches up to 93.7% while, simultaneously, the absorption coefficient is below 30% in the frequency ranges from 4 GHz to 8 GHz and 11 GHz to 13 GHz which also makes it possible to be used as a reflector. This means the device introduced is a collection of an absorber and a reflector. In addition, the radius of cylindrical copper, parameter r, can be adjusted to control the sequel of the absorption bandwidth and reflection bandwidth. Furthermore, the presented absorber is insensitive to the polarization angle.