Stretchable and Dynamically Tunable Attenuator Based on Graphene

In this article, a flexible, stretchable, and dynamically tunable attenuator based on coplanar waveguide (CPW) and graphene is proposed. Soft silicone elastomer and serpentine metal structure are used to realize the flexible, stretchable, and biocompatible characteristics of the CPW. A graphene sandwich structure (GSS) is placed on the upper surface of the CPW to dissipate the electromagnetic wave, achieving the dynamically adjustable characteristics of the stretchable attenuator. When the surface impedance of the GSS is tuned by applying a proper bias voltage, the simulated and measured results reveal that the attenuation tuning range is dynamically tuned from 4-11 dB with a low reflection below -10 dB. In addition, the fabricated attenuator is simultaneously optimized to work at conditions of the normal state, 180 degrees bending and 130% stretching, with acceptable changes between insertion loss and return loss up to 6 GHz. The attenuator covers the medical frequency band of 2.4-2.483 GHz and the 5th generation (5G) communication frequency band of 3.5-3.8 GHz, which demonstrates that the attenuator has potential applications in stretchable electronic systems.