Figure 3: Graphene IC measured as RF amplifier.

(a) Output spectrum of the IC with 900 nm gate length under −1.6 V V_d with input power of −20 dBm at 4.8 GHz. (b) Normalized amplifier output power as a function of the first-stage gate bias (V_g,1). The second-stage gate bias (V_g,2) was kept at −0.13 V and the third-stage gate bias (V_g,3) was kept at 0.99 V. (c) Normalized amplifier output power as a function of V_g,2. V_g,1=0.45 V and V_g,3=0.99 V. (d) Normalized amplifier output power as a function of V_g,3. V_g,1=0.45 V and V_g,2=−0.13 V. (e) Variation of amplifier gain during bias stress test for over 22 h. The circuit was measured in air.