Abstract The effect of concentration distribution on the performance of a static concentrator cell with a new three-dimensional lens was investigated to design an optimum cell structure. A concentration distribution of this lens was simulated using a ray-tracing method. Based on these results, fill factors were calculated as a function of series resistance and irradiance to clarify the effect of concentration distribution. The effect of concentration distribution appeared when series resistance is larger than 0.2 Ω cm 2 and irradiance is higher than 30 mW/cm 2 .