In this paper, two low profile, single fed cavity backed slot antennas for producing circular polarization (CP) wave are introduced. One of the structures presents right handed CP (RHCP), while the other one offers left handed CP (LHCP). A single layer of low cost printed circuit board (PCB) is employed for both antennas providing low cost, light weight and also easy integration with planar circuits. An inset microstrip line is used to excite two orthogonal modes, TE120 and TE210, with 90° degree phase difference for generating CP wave. Antenna structure is numerically evaluated using High Frequency Structure Simulator (HFSS) and results including reflection coefficient, gain, and axial ratio (AR), and radiation patterns are reported.