A new charge-based continuous model for long-channel Symmetric Double-Gate Junctionless Transistors (SDGJLTM) is proposed and validated with simulations for doping concentrations of 5 x 10(18) and 1 x 10(19) cm(-3), as well as for layer thicknesses of 10, 15 and 20 nm. The model is physically-based, considering both the depletion and accumulation operating conditions. Most model parameters are related to physical magnitudes, and the extraction procedure for each of them is well established. The model provides an accurate description of the transistor behavior in all operating conditions. Among important advantages with respect to previous models are the inclusion of the effect of the series resistance and the fulfilment of the requirement of being symmetrical with respect to V-d = 0 V. (C) 2013 Elsevier Ltd. All rights reserved.