A circularly polarized printed antenna using an asymmetric open-slot is designed in this paper. The presented antenna consists of conducting ground plane with open wide-slot, fed electromagnetically by a microstrip feedline. The slot and feedline are positioned at the edge of the ground plane and substrate, hence making the antenna asymmetric. The measured results show that the |S11| < −10 dB impedance bandwidth is 125% (3.2‐14 GHz) and the broadband axial ratio bandwidth is 61% (3.2‐6 GHz). The antenna is very simple and has a small size of 25 mm × 25 mm, making it attractive for compact wireless WLAN, ISM, WiMAX, and C‐band applications.