Tunable and input-matched attenuator based on few-layer graphene

This paper presents a novel tunable microstrip attenuator, based on few-layer graphene flakes. The attenuator consists of a microstrip line with two pairs of graphene pads located between the microstrip line and metal vias, positioned at the two sides of the microstrip line. In the proposed device, the insertion loss can be changed electronically by varying the applied control voltage. The structure is designed in such a way, that the attenuation is mainly due to dissipation, while minimizing the reflection contribution. A prototype of the proposed structure has been fabricated and experimentally verified. It operates in a frequency band of DC to 10 GHz, with 25 dB tunability and minimum insertion loss of 1.5 dB.