A multifunctional metastructure with dual modulation based on gravity and graphene

Abstract

Tunable metastructur (MS) is popular for research today, but it is complex and difficult to manipulate, so a novel solution has been proposed. In this paper, a MS based on gravitational field and graphene modulation is presented, which can achieve polarization conversion, amplitude modulation, and operating band shift in the range of the gigahertz (GHz) band. The proposed polarization converter (PC) consists of mercury-filled glass cavities, graphene resonators, a copper substrate, and a polyimide dielectric layer. The mercury flows to different parts through the specially designed glass cavities under the effect of the gravitational field, which results in different functions. When the proposed device is not flipped, within 2.53–4.38 GHz (the relative bandwidth is 54.28 %), the linear-polarized electromagnetic wave can be efficiently converted to the circular-polarized ones, whose axial ratio is less than 3 dB. Moreover, when it is flipped, the designed PC can realize the function of cross-polarization conversion and maintain a polarization conversion rate above 90 % in the band of 3.92–7.36 GHz (the relative bandwidth is 60.99 %). The joint tuning of graphene and gravitational field and related parameters are discussed. Moreover, the physics mechanism of the proposed device is explained according to the surface current diagrams. The proposed PC possesses the advantages of broadband, novel tuning, multifunctional modulation, etc. It can be used in the field of communication, electromagnetic countermeasures, and the electromagnetic wave modulation field.