Millimeter-wave graphene-based varactor for flexible electronics

This paper presents the design, fabrication, and characterization of the first millimeter-wave Graphene-based varactor on flexible substrates. The varactor achieves quality factor better than 10 up to 25 GHz with variation of 5–10% for a bending radius down to 5 mm with pronounced varactor behavior measured up to at least 70 GHz. To prove the substrate independence of the proposed varactor, we fabricated it on high resistivity silicon (HRS) achieving quality factors of 6 at 20 GHz, and on Quartz substrate achieving quality factors of 10 up to 50 GHz. Measurement results promote the proposed varactor for millimeter-Wave circuits and systems applications, especially on flexible substrates.