The authors have fabricated and characterized top-gated graphene transistors operating at GHz frequencies. The intrinsic current gain of these transistors exhibits an ideal 1/f frequency dependence, indicating FET-like behavior. The cutoff frequency \( f_T \) is found to be proportional to the dc transconductance \( g_m \) of the device, consistent with the relation \( f_T = g_m / (2\pi C_G) \). The peak \( f_T \) increases with a reduced gate length, and a graphene transistor with a 150 nm gate length achieves a peak \( f_T \) of 26 GHz. This work represents a significant step towards realizing graphene-based electronics for high-frequency applications. The study also highlights the importance of optimizing the oxide environment to enhance the high intrinsic mobilities of graphene.The authors have fabricated and characterized top-gated graphene transistors operating at GHz frequencies. The intrinsic current gain of these transistors exhibits an ideal 1/f frequency dependence, indicating FET-like behavior. The cutoff frequency \( f_T \) is found to be proportional to the dc transconductance \( g_m \) of the device, consistent with the relation \( f_T = g_m / (2\pi C_G) \). The peak \( f_T \) increases with a reduced gate length, and a graphene transistor with a 150 nm gate length achieves a peak \( f_T \) of 26 GHz. This work represents a significant step towards realizing graphene-based electronics for high-frequency applications. The study also highlights the importance of optimizing the oxide environment to enhance the high intrinsic mobilities of graphene.