The topic of a simulated radiation efficiency larger than unity (100%) has appeared frequently on this forum. As far as I am aware, results obtained with Ansoft HFSS and CST MWS have been discussed. In a recent paper, simulation results for the radiation efficiency of low-loss antennas (with required efficiency of 97% or higher) are shown. These results have been obtained with 5 different simulators (Ansoft HFSS, CST MWS, Ansoft Designer, FEKO, and an in-house moment code). Explanations for the efficiency results, either lower or higher than 100%, are provided. Moreover, in the discussion on the different computational procedures for the radiation efficiency, also the simulators Zeland IE3D and Sonnet are considered. Hopefully the paper can help in the understanding of problems arsing in the simulation of the radiation efficiency of (low-loss or lossless) antennas. Data of the paper: R. Maaskant, D.J. Bekers, M.J. Arts, W.A. van Cappellen, and M.V. Ivashina, Evaluation of the Radiation Efficiency and the Noise Temperature of Low-Loss Antennas, IEEE Antennas and Wireless Propagation Letters, Vol. 8, pp. 1166 – 1170, 2009.