The Automatic Gain Control (AGC) systems based on nanoscale Field Effect Diode (FED) and double gate silicon on insulator (SOI) MOSFET are investigated in this paper. Using double gate devices leads to more flexibility in gain controlling, improving performance, and power consumption reduction. Simulation results show these systems have better characteristics in terms of power and band-width in comparison with AGC system based on regular MOSFET. Among proposed alternative structures (SOI-MOS, MOSFET, FED), nanoscale FED is specifically suited for variable gain amplifier circuits in AGC systems which leads to improve performance and reduce power consumption in low-power applications. © IEICE 2010.