This work presents the design, fabrication and characterization of a low-cost Fresnel lens array in polymeric material, which acts as infrared radiation concentrator. A mold insert was fabricated in hard steel by a laser ablation process, and a polymer replica was generated by thermo injection process. The lens array is to be used in passive infrared motion sensor applications. The sensor's operation is based on pyroelectric effect, and works in the 8-14 μm wavelength range. Tests were carried out in order to quantify the sensor's detection range as well as field of view, and the results were compared with other lens commercial available. As a result, the proposed lens array presents a detection capability as good as those of reference lens.