Abstract: A printed square ring slot antenna is proposed to achieve circularly polarized (CP) radiation by using a microstripline feeding at 45° from an asymmetry introduced in the ring slot structure. Three pairs of slits are applied in the proposedprototype for reducing the antenna size, while the centre CP frequency is seen to be lowered by about 10% compared to the casewithout slits. The proposed slot antenna has the simulated axial ratio (AR) bandwidth of about 4.7%, and at the centre CPfrequency of 1362MHz 0.34dB AR is obtained.