▎ 摘　　要

NOVELTY - The circuit has a second capacitor (220) that is connected to a first capacitor (210). A graphene FET (100) is connected to the first capacitor and the second capacitor. The graphene FET is adapted for implementing a channel with graphene. Drain and a source are connected in parallel with the second capacitor. The total impedance of variable impedance circuit is determined according to the input voltage. The graphene FET flows a current between the drain and the source due to the HOLE conductivity, when the input voltage is below a certain value. USE - Impedance varying circuit used in multiband power amplifier (claimed) and in matching circuit of high output power amplifier. ADVANTAGE - The flexibility characteristic of the graphene FET is improved. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of an impedance variable circuit configuration using a graphene FET. Graphene FET (100) Capacitors (210,220)